 

                   
 

..
N. 1.:
I .2.
in.
I.-
5
a.

.1.

‘u‘ 2
.z .
4“». F
a... I
.
'-
.vhm

     

2 2r); ﬂan:

V 2 .v . ‘
3.. r. .91

                     

  

         

                     

 

 

  

 

 

  

5
«Jana?»
:. s . r7 . v 9
Fusesxww g“. .3 :2. . .
. E . . 5.2: at .
.ﬁ . is. . v!
z. . 3.2
3 . . .V.»
$6M. .
2 .
Jht "on. Sail“: . n: l .51\ 2
. 3.7.x...“ :uﬁﬁniii .
.. -. . a .9...”
I

      

F ﬁguﬁmnr! .

‘ 1’
.. a: ..:.......m

              
          

 

   

  

.3. l .
3..."...v

 

a :
... .2
53955.1:
. r .5 v.
fqéﬂfnzl
i. . 5.
FE???
2:13.?

   

 

 

  

      

 

‘
[{v: .0... 1-, ’mr
.15....23 21...? .
. L325}.
21.114

       

       

.. :30“? .
3W5. guard! . , . . r.
. s . . . . . . . . . a. it‘- JK LI» 1
. . . .. . .42: .3... 7%.”: .i p.
, . . . {gm .mmﬂumﬁm

\
.n.
I
cum}: "ML-.1311..-

 

 

        

 

V: .'
55
i... ..
5;. Run»?!
«quizxduqkﬁm
\lnﬁnh illitf‘vlumv;

 

   

  

. 3.5.2»...

  

    

35:51.- .
LII.) 5.51-3-
vb‘ s . .33).:

 

. . .19) .1» ‘3!
. than”: an)!!!
:4: .{...!.r.c....
... pngur.“ .ol. .
than»;

      

 

 

 

 

 

 

 

 

 

 

      

    

   

        

 

 

 

 

 
   

tr... 1.391% Neal? O x I .mu...;W< 2., ...L 2. ..n... E . . 2. ...2 ., , . o. .1. . P .
r1... 3...»? 459...? #5.? . : x, A....w...éw.....¢e»§2x¥¥u_._...... .i 1:. :2... .m

'0 \ .'. ‘ ’ 1|" I

 

 

 

l IHIIUUIWIIIHI”UlllllllllllllllllJHIHIIIYIHHIIWI

302074 1140

LE? MAW!
Michigan :‘éza:-~.: .
University .

 

 

This is to certify that the
thesis entitled
DRY EDIBLE BEAN RESPONSE TO
DIMETI-IENAMID AND METOLACHLOR
presented by

Kyle William Poling

has been accepted towards fulﬁllment
of the requirements for

M. S. degree in_C:gp_and_Soil Sciences

 

d

Major professor

Date IQ‘J3‘93

0-7639 MS U is an Aﬁb’mutt’w Action/Equal Opportunity Institution

PLACE IN RETURN Box to remove this checkout from your record.
TO AVOID FINES return on or before date due.
MAY BE RECALLED with earlier due date if requested.

 

DATE DUE DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11m chlRCID‘DmpBS-p.“

DRY EDIBLE BEAN RESPONSE TO
DIMETHENAMID AND METOLACHLOR

By

Kyle William Poling

A THESIS
Submitted to
Michigan State University

in partial fulﬁllment of the requirements
for the degree of '

MASTER OF SCIENCE

Department of Crop and Soil Sciences

1 999

ABSTRACT

DRY EDIBLE BEAN RESPONSE TO APPLICATIONS OF
DIMETHENAMID OR METOLACHLOR

By

Kyle William Poling

Dimethenamid and metolachlor are chloroacetamide herbicides that are applied in dry
edible beans (Phaseolus vulgaris) to control annual grasses, small-seeded broadleaf weeds,
and yellow nutsedge (Cyperus esculentus L.). Metolachlor has become the standard
herbicide treatment for preemergence grass control in dry beans since registration in 1983.
Dimethenamid was registered for use in dry beans in 1996. During that year some dry bean
ﬁelds in Michigan that received an application of dimethenamid were injured. Research was
conducted (1) to determine if dry bean classes and/or varieties differed in their susceptibility
to applications of dimethenamid or metolachlor, (2) to determine if placement or application
timing of dimethenamid inﬂuenced dry bean tolerance to dimethenamid, and (3) to determine
whether environmental conditions at the time of planting and emergence inﬂuenced dry bean
tolerance to applications of dimethenamid or metolachlor.

In a greenhouse study navy and black beans were more susceptible to dimethenamid
than pinto, kidney, small red, and cranberry classes of dry beans. Cultivars within the same
class of dry beans differed in their tolerance to applications of dimethenamid and metolachlor
in both the greenhouse and the ﬁeld. Dimethenamid was usually more injurious to dry beans

compared to metolachlor.

In our greenhouse research, injury to ‘Vista’ navy beans was greatest when
dimethenamid or metolachlor was absorbed by the hypocotyl rather than the roots. Dry bean
injury from dimethenamid or metolachlor resulted in a reduction of leaf area early in the
growing season. Visual injury and leaf area reduction also resulted in delayed maturity and
yield loss in some instances. In the ﬁeld dimethenamid and metolachlor were each applied
preplant incorporated (PPI), preemergence (PRE), and at the early crook stage, imifoliate,
1St trifoliate, and 2"d trifoliate growth stages to ‘Vista’ navy bean. When dimethenamid and
metolachlor were applied at the crook and unifoliate stages the leaf area was reduced from
21 to 34% when measured at the 3rd trifoliate growth stage. To minimize the chance of
severe injury, these herbicides should not be applied at the crook or unifoliate stages.

Environmental conditions following application of dimethenamid or metolachlor
affected dry bean tolerance to these herbicides. The quantity of precipitation that a dry bean
ﬁeld received at the time of emergence following a preemergence application of
dimethenamid or metolachlor was important. Rain at the time of emergence appears to
increase the amount of herbicide absorbed by the dry bean hypocotyl which resulted in crop
injury. Moderate temperature (22 to 31 C) did not appear to play a signiﬁcant role in dry

bean injury from dimethenamid or metolachlor in our research.

ACKNOWLEDGMENTS

I would to express my sincere gratitude and apprectiation to Dr. Karen Renner for the
instruction, patience, encouragement, and friendship she provided during my two years at
Michigan State University. My appreciation is also extended to Dr. Donald Penner, Dr.
James Kelly, and Dr. Bernard Zandstra for their assistance while serving on my guidance
committee.

I would like to thank to Gary Powell for his technical assistance in the ﬁeld and for
making those long days in the ﬁeld enjoyable. Special thanks to my fellow graduate students
Joe Simmons, Kelly Nelson, Chad Lee, Jason Fausey, Nate Kemp, Sherry White, Brent
Tharp, Christy Sprague, and Caleb Dalley for their advice and ﬁ'iendship.

My parents, Steve and Debbie, deserve a special thanks for their love, guidance, and
support. I would like to thank my brothers, Doug and Chris, for continuously encouraging
me to shoot for the stars. A special thanks to my wife, Lori, for her unconditional love,
undying support, and belief in my abilities to succeed in all I do. To the Lord Jesus Christ

for giving me the strength and perseverance needed to complete my graduate degree.

iv

TABLE OF CONTENTS

LIST OF TABLES ..................................................... vii

LIST OF FIGURES ...................................................... x

Chapter 1. LITERATURE REVIEW
Weed Control Strategies ............................................ 1
Market Classes .................................................... 1
Cultivar Selection .................................................. 2
Date of Planting ................................................... 5
Weed Competition ................................................. S
Cultivation ....................................................... 8
Chemical Control ................................................. 10
Chloroacetamide Herbicides ........................................ 13
Literature Cited .................................................. 18

Chapter 2. TOLERANCE OF DRY BEAN CLASSES AND CULTIVARS TO
DIMETHENAMID AND METOLACHLOR

ABSTRACT ..................................................... 24
INTRODUCTION ................................................ 26
MATERIALS AND METHODS ..................................... 28
Greenhouse Study .......................................... 28
Emergence Study ........................................... 29
Field Screen ............................................... 30
F3 Study .................................................. 32
RESULTS AND DISCUSSION ..................................... 33
Greenhouse Study .......................................... 33
Emergence Study ........................................... 34
Field Screen ............................................... 35
F3 Study .................................................. 36
SUMMARY ..................................................... 37
LITERATURE CITED ............................................ 38

Chapter 3. DRY BEAN RESPONSE TO DIMETHENAMID AND METOLACHLOR
AS INF LUENCED BY TIMING OF APPLICATION

ABSTRACT ..................................................... 46
INTRODUCTION ................................................ 47
MATERIALS AND METHODS ..................................... 48
Greenhouse Placement Study ................................. 48
Volatility Study ............................................ 50
Site of Uptake Experiment .................................... 51
Timing of Application Study .................................. 53
Dimethenamid / S-dimethenamid .............................. 54
Postemergence Application of Basagran Plus Dimethenamid ......... 55
RESULTS AND DISCUSSION ..................................... 56
Greenhouse Placement Study ................................. 56
Volatility Study ............................................ 58
Site of Uptake Experiment .................................... 58
Timing of Application Study .................................. 58
Dimethenamid / S-dimethenamid .............................. 60
Postemergence Application of Basagran Plus Dimethenamid ......... 61
SUMMARY ..................................................... 62
LITERATURE CITED ............................................ 64

Chapter 4. INFLUENCE OF ENVIRONMENTAL CONDITIONS AT THE TIME OF
PLANTING AND EMERGENCE ON DRY BEAN TOLERANCE TO
DIMETHENAMID AND METOLACHLOR

ABSTRACT ..................................................... 71
INTRODUCTION ................................................ 72
MATERIALS AND METHODS ..................................... 74
RESULTS AND DISCUSSION ..................................... 76
SUMMARY ..................................................... 78
LITERATURE CITED ............................................ 80

vi

LIST OF TABLES

Chapter 1. LITERATURE REVIEW
Table 1 - Herbicides registered for use on dry beans ...................... 23

Chapter 2. TOLERANCE OF DRY BEAN CLASSES AND CULTIVARS TO
DIMETHENAMID AND METOLACHLOR

Table 1 - Dry bean injury from dimethenamid preemergence at 2.1 kg ha'1 (twice
the recommended rate) ...................................... 39

Table 2 - Time to emergence and diameter of the hypocotyl at the crook stage of
14 different cultivars of dry beans ﬁom six classes ................ 40

Table 3 - Injury and leaf area at the 1St trifoliate resulting from dimethenamid and
metolachlor applied PRE in 1998 ............................. 41

Table 4 - Dry bean maturity and seed yield following PRE applications of
dimethenamid and metolachlor in 1998 ......................... 42

Table 5 - Injury and leaf area at the 1St trifoliate growth stage resulting from PRE
applications of dimethenamid and metolachlor in 1999 ........... 43

Table 6 - Dry bean maturity and seed yield following PRE applications of
dimethenamid and metolachlor in 1999 ........................ 44

Chapter 3. DRY BEAN RESPONSE TO DIMETHENAMID AND METOLACHLOR
AS INFLUENCED BY TIMING OF APPLICATION

Table 1 - Response of six dry bean cultivars to preplant incorporated and
preemergence dimethenamid and metolachlor in the greenhouse . . . . 65

Table 2 - Effect of different parts of dry bean seedlings to dimethenamid and
metolachlor-treated soil using charcoal barriers to prevent movement of
the herbicide .............................................. 66

vii

Table 3 - Effect of timing of application of dimethenamid and metolachlor on

‘Vista’ navy beans in 1998 and 1999 ........................... 68

Table 4 - Effect of applications of dimethenamid and S-dimethenamid when

applied PRE and at the 1“ trifoliate growth stage on ‘Schooner’ navy
beans in 1998 and 1999 ..................................... 69

Table 5 - ‘Vista navy bean injury and yield following application of various tank-

mixtures of dimethenamid, bentazon, dimethoate, and crop oil
concentrate (COC) at the 1“ and 2'”d trifoliate growth stages combined
over 1998 and 1999 ........................................ 70

Chapter 4. INFLUENCE OF ENVIRONMENTAL CONDITIONS AT THE TIME OF
PLANTING AND EMERGENCE ON DRY BEAN TOLERANCE TO
DIMETHENAMID AND METOLACHLOR

Table 1 - Injury on ‘Vista’ and ‘Schooner’ navy bean from dimethenamid at 2.3

kg ha’1 and metolachlor 2.8 kg ha’1 PRE at the l"t trifoliate growth stage
on ﬁve planting dates in 1998 and 1999 ........................ 82

Table 2 - Effect of dimethenamid at 2.3 kg ha‘1 and metolachlor 2.8 kg ha’1 PRE

on ‘Vista’ and ‘Schooner’ navy dry bean leaf area at the 1“ trifoliate
growth stage on ﬁve different planting dates in 1998 and 1999 ...... 83

Table 3 - Effect of dimethenamid at 2.3 kg ha‘1 and metolachlor at 2.8 kg ha‘1 PRE

on ‘Vista’ and ‘Schooner’ navy bean maturity from ﬁve planting dates in
1998 and 1999 ............................................ 84

Table 4 - Effect of applications of dimethenamid at 2.3 kg ha‘1 and metolachlor at

2.8 kg ha‘1 PRE on dry bean yield from ﬁve planting dates in 1998 and
1999 .................................................... 85

Table 5 - Mean temperature (10 DAP), rainfall intervals (10 DAP) and

APPENDIX

accumulative rainfall at the crook stage at each date of planting in 1998
and 1999 ................................................. 86

Table 1 - Effect of applications of dimethenamid and metolachlor PRE on ‘Vista’,

‘Schooner’, and ‘Newport’ navy dry bean and ‘Midnight’ and ‘T-39’
black bean leaf area at the unifoliate growth stage in 1998 and 1999 . . 87

viii

Table 2 - Effect of applications of dimethenamid and metolachlor PRE on
‘Vista’, ‘Schooner’, and ‘Newport’ navy dry bean and ‘Midnight’ and
‘T-39’ black bean leaf area at the 3rd trifoliate growth stage in 1998 and
1999 .................................................... 88

Table 3 - Effect of applications of dimethenamid at 2.3 kg ha’1 and metolachlor at
2.8 kg ha" PRE on ‘Vista’ and ‘Schooner’ navy dry bean leaf area at the
unifoliate growth stage in 1998 and 1999 ...................... ,. 89

Table 4 - Effect of applications of dimethenamid at 2.3 kg ha’1 and metolachlor at

2.8 kg ha'1 PRE on ‘Vista’ and ‘Schooner’ navy dry bean leaf area at the
3rd trifoliate grth stage in 1998 and 1999 ..................... 9O

ix

LIST OF FIGURES

Chapter 2. TOLERANCE OF DRY BEAN CLASSES AND CULTIVARS TO
DIMETHENAMID AND METOLACHLOR

Figure 1 -Relationship between seed size to visual leaf area reduction 7 days after
dimethenamid applied postemergence to the F 3 progeny of ‘Huron’ navy
bean crossed with ‘Matterhorn’ great northern bean ............... 45

Chapter 3. DRY BEAN RESPONSE TO DIMETHENAMID AND METOLACHLOR
AS INFLUENCED BY TIMING OF APPLICATION

Figure 1 - Position of charcoal layers, untreated soil, and herbicide-treated soil for

exposure of dry beans to dimethenamid and metolachlor to determine site
of uptake ................................................. 67

Chapter 1

LITERATURE REVIEW

Weed Control Strategies

Drybean farmers use a combination of mechanical, cultural, and chemical practices
in their weed management systems (Burnside et al., 1994). A survey conducted in 1989
showed that the major production problem for Minnesota and North Dakota dry bean
growers was the control of weeds (Lamey et al., 1991). Dry bean farmers use various
methods to control weeds in their ﬁelds. Today an integrated weed management strategy
could include any combination of the following practices: class and cultivar selection,
narrow row spacing, and increased seeding density (Malik et al., 1993), as well as planting

date, herbicides and cultivation (Leep et al., 1982).

Market Classes

A dry edible bean (Phaseolus vulgaris) market class is a category that classiﬁes a dry
edible bean according to size and color of seed. Navy beans are white in color and are
considered small in size (17-22 g/ 100 seeds) relative to other classes of dry beans. Black (or
black turtle) beans, which genetically are closely related to navy beans, are of similar size
to navy beans with a black seed coat. The pinto class of dry beans is tan with dark brown
mottling and has a medium seed size (38-42 g/ 100 seeds). Pinto beans are distantly related

1

to both navy and black beans. Great northern and pink beans are similar in size and shape
to the pinto class but with a brilliant white and pink seed coat, respectively. The small red
or red Mexican market class is a red bean and is slightly smaller than a pinto bean. The
pinto, great northern, pink and small red market classes are all closely related genetically
(Voysest and Dessert, 1991). Cranberry dry beans have a white-red mottled seed coat and
are medium-large in size (45-55 g/ 100 seeds). Light red and dark red kidney beans are the
largest seed of all the market classes (50-60 g/ 100 seeds). The two kidney bean classes and
cranberry market class are closely related.

The total number of acres of each class of dry beans grown can vary dramatically
from year to year. This ﬂuctuation is a direct effect of the price a grower can receive for a
bag (100 lbs) of dry beans in the months preceding planting. Since navy beans and black
beans are well suited for the climate in Michigan, these market classes account for the
majority of dry beans grown. In 1997 Michigan farmers produced 5,033,000 cwt of dry
beans ranking the state as the second largest producer in the country. Almost one-half (48%)
of the total acres planted in Michigan in 1997 were of the navy bean class and 25% were
black beans. The following year the acres planted in the state declined from 315,000 to
300,000. Navy bean accounted for 28% of the total dry beans grown in 1998 while black

bean acreage increased greatly to nearly 42% (Varner, 1999 personal communication).

Cultivar Selection
One of the ﬁrst weed control decisions that confronts a grower is related to the seed
selection process. Cultivars of common beans differ in their competitive ability with weeds

2

(Malik etal., 1993). These differences, attributed to inherent genetic variation (Monks and
Oliver, 1988), can include seedling establishment and canopy development (Field and
Nkumbula, 1986). It is important to select a bean cultivar that emerges evenly and
vigorously ﬁom the soil and has a high percent germination to enable the crop to become
well established before weeds begin to germinate (Robertson and Frazier, 1978). Fields with
reduced plant populations suffer most by the presence of weeds (Burnside, 1979; Goulden,
1976). However, research has shown that white beans have some ability to compensate for
reduced plant stands (Field and Nkumbula, 1986).

Dry edible beans have two basic plant types, determinate (bush) or indeterminate
(Vining or trailing). Cultivars of a particular market class may be classiﬁed according to
plant type. In the determinate type, main stem elongation ceases when the terminal ﬂower
racemes of the main stem or lateral branches have developed. The indeterminate type will
continue to ﬂower and ﬁll pods either simultaneously or alternately as long as temperature
and moisture permit growth to occur.

In addition to being classiﬁed as either determinate or indeterminate plant types, four
plant growth habits have been identiﬁed. Type I plants, the only one of the four growth
habits that possesses the determinate ﬂowering pattern, have a bush style plant architecture.
Plants of Type H growth habit are indeterminate with short, upright vines, a narrow proﬁle,
and have three to four stems. Dry beans of Type HI and Type IV growth habits also have an
indeterminate ﬂowering pattern. The architectural tendency of Type 111 plants are prostrate

and viney while Type IV plants have strong climbing tendencies (Singh, 1982).

Malik et a1. (1993) studied three navy bean cultivars in Ontario. They reported that
the indeterminate cultivars OAC Laser and OAC Gryphon (Type II and Type III growth
habit, respectively) reduced overall weed biomass compared to OAC Sprint (Type I growth
habit). The OAC Sprint cultivar ceased vegetative grth at ﬂowering when weeds were
still actively growing. The later maturing Type H and III cultivars that continued to grow
after ﬂowering were more competitive with weeds than the early maturing Type I cultivar.
The major weed species that were present included redroot pi gweed (Amaranthus retroﬂexus
L.), common lambsquarters (Chenopodium album L.), barnyardgrass (Echinochloa crus-galli
(L.) Beauv.), and green foxtail (Setaria viridis L.). The continued grth of the
indeterminate cultivars reduced total weed biomass 11 to 35% compared with the
determinate cultivar.

In a study conducted in western Nebraska, differences in weed control in determinate
and indeterminate great northern varieties were evident. In plots treated with EPTC the
densities of redroot pigweed, black nightshade (Solanum nigrum L.), and bristly foxtail
(Setaria verticallata L. Beauv.) at harvest were signiﬁcantly higher in the determinate variety
Great Northern 1140 compared to the indeterminate variety Tara. When these varieties
received a preplant application of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-
(methoxymethyl)acetamide], black nightshade densities were higher in plots seeded with
‘Great Northern 1140’ as compared to plots seeded with ‘Tara’. Yields of ‘Tara’ were
signiﬁcantly higher than ‘Great Northern 1140’ after treatment with either EPTC or alachlor
and, under weed free conditions and a long growing season ‘Tara’ yielded more than ‘Great

Northern 1140’ (Wilson et al., 1980).

Date of Planting

Dry beans should be planted into warm (>55 F), moist soil to obtain a good plant
stand. If the soil at planting depth is dry, farmers should wait for a rain rather than planting
into dry soil (Erdmann and Adams, 1982). Planting dry beans in May is generally not
desirable because the potential for root rot, green regrowth, and erratic yields is increased.
Planting after June 30 raises the chance of white mold infection or reduced bean quality ﬁom
frost damage (Varner, 1999 personal communtication).

Date-of-planting trials were conducted in Michigan ﬁ'om 1986 to 1990 (Varner,
1999). Optimum planting dates were found to be June 1 to 10 for ﬁrll-season beans (>98
days), June 5 to 20 for mid-season beans (91-98 days), and June 10 to 25 for early maturing
beans (590 days). Temperature and rainfall during the critical periods of ﬂowering and pod
ﬁll have a direct effect on yield potential. Spacing out planting dates and/or planting
varieties with varying maturity dates will stagger the blossom and harvest dates, which in

turn spreads out the risk of raising dry beans.

Weed Competition

Dry beans, being a short duration and slow growing crop, suffer more from weed
competition than most other row crops (Verma and Bhardwaj, 1963). Weeds that emerge
above the bean canopy are the most competitive (Dawson, 1964). Uncontrolled populations
of weeds can reduce white bean yields by as much as 70% (Woolley et al., 1993). A number
of different factors inﬂuence the extent to which weeds affect cr0p yields. These include
weed-related factors such as time of emergence and density, as well as environmental factors

5

and management practices that affect both crop and weed deve10pment (Chikoye et al.,
1996).

The critical period of weed control represents the time interval between two different
components (Hall et al., 1992). The ﬁrst component is the maximum length of time weeds
can remain in a crop before losses in yield occur. The second component is the length of
time a weed free environment must be maintained to prevent yield reduction (Weaver and
Tan, 1983). The critical period for weed control in dry beans is between 3 and 6 weeks after
planting (Burnside et al., 1998).

Weeds compete with dry beans for light, nutrients, and water thereby reducing crop
yield and economic return (Blackshaw, 1991). Even when weeds are removed with a
cultivator from between the rows, weeds remaining in the rows may reduce yields
substantially. Noticeable yield differences were seen when cultivation alone was compared
to cultivation plus rotary hoeing. In a ﬁeld trial, the additional weed control gained from the
rotary hoeing increased bean yields by 384 pounds per acre one year and 732 pounds the next
year (Leep et al., 1982).

Growers in the state of Minnesota identiﬁed foxtails (Setarz‘a spp.), redroot pigweed,
common ragweed (Ambrosia artemisiifolia L.), common lambsquarters, nightshades
(Solanum spp.), common cocklebur (Xanthium strumarium L.), and wild mustard (Brassica
kaber (DC.) L.C. Wheeler) as their most competitive weeds (Lamey et al., 1991). Most
grasses can be effectively controlled with the grarninicides labeled for use in dry beans.
Unfortunately, similar success in controlling broadleaf weeds has not been reached

(Blackshaw and Esau, 1991).

The problem of nightshades in agriculture has increased greatly over the last 25 years
(Ogg and Rogers, 1989). Nightshade species begin germinating two to three weeks after dry
beans are planted and continue to germinate through the middle of August (Leep et al.,
1982). In a two year study conducted by Blackshaw (1991), as few as 2 hairy nightshade
(Solanum sarrachoides Sendtner) plants per meter of row reduced yield by an average of
13%. As the density of hairy nightshade increased, plant biomass and seed yield of dry bean
was reduced. Dry bean yields in Alberta were reduced by over 80% by hairy nightshade
(Basset and Munro, 1985). In addition to causing lower crop yields, nightshade causes
harvesting problems, a reduction in crop quality, and the risk of toxicity in a food crop (Ogg
and Rogers, 1989).

Common ragweed is a major weed escape in white bean ﬁelds throughout Ontario.
Chikoye et a1. (1996) found that the time of emergence and density of ragweed inﬂuenced
crop yield. When a population of 1.5 ragweed plants per meter of row emerged with the dry
bean crop, 10 to 22% yield loss occurred. When the same density of ragweed seedlings (1.5
plants rn‘l of row) emerged at the V3 crop stage, yield reduction was only 4 to 9%. In snap
bean (Phaseolus vulgaris L.), ragweed that competed with the crop for the ﬁrst 30 days of
crop growth reduced total yield by 30%. When 120 ragweed plants In1 competed with snap
bean for 90 days, yield losses reached 75% (Lamey et al., 1991). Common ragweed
decreased snap bean yields more when interference occurred between ﬂower initiation and
harvest compared with interference during the period before ﬂowering (Evanylo and Wilson,

1988).

Neary and Majek (1990) determined the maximum amount of time common
cocklebur could remain in snap bean and not cause a signiﬁcant yield loss. Similar to
common ragweed, the time in which cocklebur was most competitive with snap beans was
between full bloom and harvest. From the time between ﬁrll bloom and harvest of snap bean,
common cocklebur attained 38 and 67% of it's total height and weight, respectively. During
this same time period the snap beans attained approximately 16% of their total height and
18% of their total weight. Weeds were shorter than snap beans until full bloom at which
time they were approximately the same height. Yields were reduced 2 to 55% by weed
densities of 0.5 to 8 rn'2 that remained in the crop all season long. If snap beans were kept
weed free until the unifoliate stage, up to 4 common cocklebur seedlings per m‘2 could

remain in the crop until harvest and not reduce snap bean yield.

Cultivation

Although dry bean herbicide technology continues to progress, the cultivator is still
an important part of a weed control program. One cultivation, performed 3 weeks after
planting, controlled 68% of broadleaf species. If dry beans were rotary hoed 1 and 2 weeks
after planting and then cultivated at 3 and 6 weeks after planting, broadleaf weed control
increased to 76%. Mechanical weed control treatments alone controlled only 65% of annual
grasses (Burnside et al., 1994). According to a study conducted among Minnesota dry bean
growers, grassy weeds are more difﬁcult to control than broadleaf weeds (Lamey et al.,

1991). However, growers do have more than a dozen mechanical plus chemical weed

management systems that control grasses in dry bean production ﬁelds (Burnside et al.,
1994)

It is common practice for farmers to apply preemergence herbicides in a 7 to 10 inch
band over each row. Weeds between the rows are then controlled mechanically (i.e.
cultivation and rotary hoeing). This practice cuts the cost of chemical weed control by nearly
one-third (Leep et al., 1982).

Aside from weed control, cultivation serves a number of other important functions.
Most growers cultivate at least once to hill beans sufﬁciently for pulling at the end of the
harvest season. Also, cultivation opens up the soil enabling both water and oxygen to ﬂow
more freely to the developing root system (Leep et al., 1982).

Many of the obvious effects of cultivation on a dry bean production system are
positive ones. However, the timing of this operation is critical. Once the dry bean plants
begin to ﬂower, cultivation should no longer be performed because a large portion of the
secondary root system has developed. The majority of these roots are located just below the
soil surface. Cultivating after this time will cause the secondary roots to be pruned which
reduces the plants’ ability to take up water and nutrients. Also, cultivating after this time can
cause ﬂower buds to be knocked off by equipment travelling between the rows. In addition,
ﬁelds should not be cultivated when plants and/or soil are wet to minimize compaction and

reduce the chance of spreading disease (Leep et al., 1982).

Chemical Control

In 1979 there were eight herbicides available for use in dry bean production.
Herbicide programs used by dry bean farmers today have changed very little since 1979. Of
the herbicides applied 20 years ago (Meggitt, 1979), four are still being used today.
Currently there are a total of twelve herbicides registered to control weeds in dry beans
(Table 1) (Renner and Kells, 1999).

Herbicide application in dry beans became more common in the mid-1960’s when
it was discovered that dry edible beans were tolerant to EPTC (Eptam) and that EPTC
provided good weed control. EPTC controls annual grasses and some annual broadleaf
weeds. EPTC must be incorporated immediately after application to avoid volatilization.
Triﬂuralin (Treﬂan) was introduced a few years after EPTC. Triﬂuralin controls early season
grasses and common lambsquarters (Leep et al., 1982). By the early 1970's the standard
chemical weed control practice in dry beans was a tank mixture of these two products.
Today over 60% of all the dry bean acres in Michigan receive a preplant incorporated (PPI)
application of EPTC + triﬂuralin (Renner, 1999 personal communication).

There are only a limited number of postemergence (POST) herbicides registered for
use in dry beans. This forces growers to rely heavily on preplant incorporated and
preemergence (PRE) herbicides for weed control. Herbicides applied PRE may provide
inconsistent weed control under less than ideal moisture conditions (Leep et al., 1982).
Three of the herbicides that are commonly applied PPI in dry beans include triﬂuralin,
ethalﬂuralin (Sonalan), and pendimethalin (Prowl). These herbicides are all dinitroanilines
and control annual grasses and common lambsquarters. Triﬂuralin and ethalﬂuralin also

10

control redroot pigweed and pendimethalin suppresses velvetleaf (Renner and Kells, 1986
to 1999). The chloroacetarrride herbicides applied PPI that are registered for use in dry beans
are alachlor (Lasso), metolachlor (Dual), and dimethenamid (Frontier). Metolachlor controls
annual grass species and redroot pigweed. Alachlor and dimethenamid control the same
weeds as metolachlor plus nightshade species. Metolachlor and dimethenamid can also be
applied PRE. Alachlor cannot be applied PRE because of a lack of tolerance in dry beans
(Renner and Kells, 1999).

There are three herbicides registered for control of annual grasses and quackgrass
postemergence in dry beans. These are sethoxydirn (Poast), quizalofop-P-ethyl (Assure II),
and clethodim (Select). These are not used on many acres because annual grasses are
controlled with soil-applied herbicides. These soil applied ‘grass’ herbicides also control
broadleaf weeds so they are an important component of the weed control program (Meggit,
1977-1985; Renner and Kells, 1986-1999).

The herbicide options to control broadleaf weeds POST are limited to bentazon
(Basagran) and imazethapyr (Pursuit). Bentazon controls velvetleaf, common cocklebur,
jimsonweed, smartweed, and wild mustard as well as Canada thistle and yellow nutsedge.
Imazethapyr controls redroot pigweed, nightshade spp., and wild mustard and can be applied
PPI, PRE, or POST. However there is a 40-month crop rotation restriction on the label for
sugarbeets. Since a large amount of the acres planted to dry beans are grown in rotation with
sugarbeets imazethapyr is not used extensively as a dry bean herbicide. Fomesafen (Reﬂex)
has been used in Michigan for the past 3 out of 4 years under a Section 18 Emergency Use
exemption (Renner, 1999 personal communication). F omesafen provides excellent control

11

of giant and common ragweed and good control of redroot pigweed and wild mustard
(Renner and Kells, 1999)

Due to the diversity of weed species that can be found in the same ﬁeld, two or more
herbicides are often tank-mixed to achieve the desired spectrum of weed control (Rhodes,
Jr. and Coble, 1984). It has been reported by several researchers that when a variety of
herbicides are applied in combination with each other overall efﬁcacy can be reduced (Beste
and Schreiber, 1972; Dortenzio and Norris, 1979; Selleck and Baird, 1981). The basis for
a number of herbicide antagonistic interactions has been a reduction in absorption and/or
translocation (Hamill et al., 1972; O’Donovan and O’Sullivan, 1982; Todd and Stobbe,
1980). It has been postulated that the Na-ion in the bentazon formulation inhibits absorption
of some herbicides (Rhodes Jr. and Coble, 1984; Wanamarta et al., 1989).

In 1991 and 1992 a postemergence application of imazethapyr at 53 g ha" to ‘Olathe’
pinto beans delayed physiological maturity by 8 and 15 days, respectively, compared to the
untreated control. Though pinto bean yields were not reduced compared to the untreated
control, the number of days to full maturity increased. Maturity of the beans was not delayed
when imazethapyr (53 g ha“) was tank-mixed with bentazon (840 g ha“). The tank mixture
of bentazon + imazethapyr decreased the amount of injury and increased the chlorophyll a
content, a quantitative measure of bean chlorosis, compared with imazethapyr alone (Bauer
et al., 1995). Further studies conducted by Bauer et al. (1995) showed that 14C-imazethapyr
absorption by ‘Olathe’ pinto beans decreased by 40% and translocation from the treated leaf
was reduced by 50% when l4C-imazethapyr was tank-mixed with bentazon compared to
14C-imazethapyr applied alone. The safening effect observed when imazethapyr and

12

bentazon were applied in combination was attributed to decreased absorption and

translocation by the dry beans.

Chloroacetamide Herbicides

The chloroacetamide herbicides are commonly used to control annual grasses,
small-seeded broadleaf weeds, and yellow nutsedge (Cyperus esculentus L.) (Anonymous,
1992). The mode of action of this group of herbicides is not completely understood. Deal
and Hess (1980) have concluded that growth inhibition of plants caused by herbicides of the
chloroacetamide group results ﬁ'om an inhibition of both cell division and cell enlargement.

The ﬁrst chloroacetamide herbicide that was registered for application in dry edible
beans was alachlor in 1978. It was applied at 2.0 lbs ai/acre in a tank mixture banded PRE
with chlorarnben (Amiben). Use of alachlor in recent years has decreased and replaced by
metolachlor and more recently dimethenamid. Metolachlor was registered for use in dry
beans prior to the 1983 ﬁeld season. Metolachlor controlled a weed spectrum similar to
alachlor, but dry beans were more tolerant to metolachlor. As metolachlor use increased in
the corn and soybean market, it’s use also increased in dry beans. In 1996 a third
chloroacetamide, dimethenamid, was registered for use in dry beans. All three herbicides
control annual grasses but the spectrum of broadleaf weed control differs. Alachlor and
dimethenamid provide good control of redroot pigweed and Eastern black nightshade.
Metolachlor controls redroot pigweed equally well but is less effective on Eastern black

nightshade (Renner and Kells, 1986-1999).

13

Cultivars of many different crops have exhibited variable tolerance levels to
chloroacetarnides (Renner et al., 1988; Driver et al., 1992; Edwards et al., 1976; Sniper et
al., 1987; Stephenson et al., 1976). In eight years of ﬁeld testing, snap bean tolerance to
alachlor ranged ﬁ'om outstanding to poor even with similar rates and applications methods.
The severity of alachlor injury to snap beans is affected by a number of different factors that
may interact. Soil type, temperature, rainfall, placement of the herbicide, and other soil
factors appear to be important factors inﬂuencing tolerance in the ﬁeld (Cieslar and Binning,
1974; Putnam and Rice, Jr., 1979).

Alachlor injured snap beans at low and high temperature regimes with day and night
temperatures of 16 and 21 C or 27 and 32 C, respectively. The type and severity of the
injury differed at the two temperature regimes. At 16 to 21 C the injury appeared much
earlier and was much more severe than injury at the high temperature. Plants at the low
temperature displayed leaf crinkling or fusion of the leaf margins. At the high temperature
plants exhibited cupping and marginal chlorosis (Putnam and Rice, 1979). Penner and
Graves (1972) found that 3.32 kg/ha (two times the normal rate) of alachlor caused injury
to navy beans at 20 and 25 C but not at 30 C. Navy bean injury by alachlor at the lower
temperatures may explain the occasional injury observed in the ﬁeld.

Putnam and Rice (1979) reported that twice as much alachlor was taken up by snap
bean at 27 to 32 C compared with 16 to 21 C. This increase in uptake may be due to
increased growth rates and higher transpiration rates at higher temperatures. At the higher

temperature regime the majority of the alachlor remained in the plant roots. At the lower

14

temperature the herbicide was distributed throughout the plants with no one part of the plant
accumulating a signiﬁcantly greater amount of alachlor than any other plant part except the
cotyledons in which no alachlor was found. The percentage remaining as parent alachlor was
greater at the lower temperature regime. Therefore lower temperatures could result in more
crop injury.

Herbicides become more available for plant uptake as soil moisture increases (Jones
et al., 1990; Tripp and Baldwin, 1988; Wehtje et al., 1987). Metolachlor uptake increased
up to three-fold in grass species when soil moisture increased from 45 to 100% (Gerber et
al., 1974.). In a ﬁeld experiment evaluating different soybean cultivars neither
dimethenamid or metolachlor reduced soybean yield when applied at normal use rates with
either optimum or excessive moisture. However, injury occurred when dimethenamid or
metolachlor were applied above recommended rates and excessive moisture conditions
persisted. Some soybean cultivars were more sensitive to dimethenamid compared with
metolachlor, but to reveal these differences a 3X herbicide rate combined with excessive
moisture were required (Osborne et al., 1992a). Other soybean studies have revealed that the
magnitude of soybean injury is often greater with dimethenamid compared with metolachlor
(Osborne et al., 1992b). There are also differences in the site of uptake of
chloroacetamide herbicides in plants. Application of metolachlor in the shoot zone of corn
(Zea mays) and barley (Hordeum vulgare L.) decreased plant height, emergence, and dry
weight but when metolachlor was applied in the root or seed zone there was no detectable

effect. When metolachlor was applied in all three zones corn and barley emergence, height,

15

and dry weight was always reduced (Pillai et al., 1979). Putnam and Rice (1979)
demonstrated that snap bean injury decreased when alachlor was applied preplant
incorporated compared to a preemergence surface treatment. This increase in crop safety
was attributed to the reduction of herbicide in the zone of emergence, thus less alachlor was
absorbed by the bean epicotyl. Early uptake of alachlor in snap bean occurred primarily via
the hypocotyl portion of the emerging seedling (Rice, Jr. and Putnam, 1980).

The organic matter and clay content affect the biological activity of alachlor and
metolachlor (Weber and Peter. 1982). Soil adsorption of herbicides is inversely related to
herbicide mobility (Weber and Best, 1972.). Eshel (1969) reported that alachlor was
adsorbed by soil colloids and thus partially inactivated in soils high in clay or organic matter.
One ppm of alachlor reduced the fresh weight of sorghum by 50% in a sand, sandy loam, and
clay loam soil. However 2 ppm of alachlor was needed to cause the same amount of
phytotoxicity to sorghum in a clay soil (Eshel, 1969).

The most prevalent way in which chloroacetarnides dissipate from the soil is by
microbial decomposition. The most favorable environment for metolachlor degradation is
warm, moist soils (Saxena et al., 1987). Volatilization plays a signiﬁcant role in dissipation
only when the soil is wet and the weather is windy (Bestrnan and Deming, 1974).
Metolachlor is the most persistent chloroacetamide. The ﬁfty percent dissipation time (DTSO)
in ﬁeld studies with metolachlor was 108 days (Saxena et al., 1987). This herbicide is

mainly broken down by microbial transformations. Repeated annual applications of alachlor

l6

or metolachlor does not increase the rate of degradation, thus microorganisms are not thought

to adapt and cause enhanced degradation (Kotoula-Syke, 1997).

17

LITERATURE CITED

Anonymous. 1992. SAN 582G experimental herbicide: A technical overview. Sandoz Agro,
Inc., Des Plaines, IL 60018.

Basset, I.J., and DB. Munro. 1985. The biology of Canadian weeds. Can. J. Plant Sci.
65:401-414.

Bauer, T.A., K.A. Renner, and D. Penner. 1995. ‘Olathe’ pinto bean (Phaseolus vulgaris)
response to postemergence imazethapyr and bentazon. Weed Sci 43:276-282.

Beste, CE. and M.M. Schreiber. 1972. RNA synthesis as the basis for EPTC and 2,4-D
antagonism. Weed Sci. 20:8-11.

Bestrnan, GB. and J .M. Deming. 1974. Dissipation of acetanilide herbicides from soils.
Agron. J. 66:308-311.

Blackshaw, RE. 1991. Hairy nightshade (Solanum sarrachoides) interference in dry beans
(Phaseolus vulgaris). Weed Sci. 39:48-53.

Blackshaw, RE. and R. Esau. 1991. Control of annual broadleaf weeds in pinto beans
(Phaseolus vulgaris). Weed Techno]. 5:532-538.

Burnside, CC. 1979. Soybean (Glycine max) growth as affected by weed removal, cultivar
and row spacing. Weed Sci. 27:562-565.

Burnside, O.C., W.H. Ahrens, B.J. Holder, M.J. Wiens, M.M. Johnson, and EA. Ristau.
1994. Efﬁcacy and economics of various mechanical plus chemical weed control systems
in dry beans (Phaseolus vulgaris). Weed Techno]. 8:238-244.

Burnside, O.C., M.J. Wiens, B.J. Holder. S. Weisberg, E.A. Ristau, M.M. Johnson, and J .H.
Cameron. 1998. Critical periods for weed control in dry beans (Phaselous vulgaris). Weed
Sci. 46:301-306.

Chikoye, D., L.A. Hunt, and C.J. Swanton. 1996. Simulation of competition for
photosynthetically active radiation between common ragweed (Ambrosia artemisiifolia) and
dry bean (Phaseolus vulgaris). Weed Sci. 44:545-554.

Cieslar, B. and L.K. Birming. 1974. Translocation of 14C-alachlor in lima beans as related
to phytotoxicity. Proc. North Cent. Weed Control Conf. 29:323.

18

Dawson, J.H. 1964. Competition between irrigated ﬁeld beans and annual weeds. Weeds
12:206-208.

Deal, L.M. and FD. Hess. 1980. An analysis of the growth inhibitory characteristics of
alachlor and metolachlor. Weed Sci. 28: 168-175.

Dortenzio. WA. and RF. Norris. 1979. Antagonistic effects of desmidipham on diclofop
activity. Weed Sci. 27:539-544.

Driver, J .E., T.F. Peeper, and AC. Guenzi. 1992. In vitro selection for increased wheat
tolerance to metsulﬁrron. Proc. South. Weed Sci. Soc. 45:316.

Edwards, C.J., Jr., W.L. Barrentine, and T.C.Kilen. 1976. Inheritance of sensitivity of
soybean cultivars to metribuzin. Crop Sci. 16:119-120.

Erdmarm, M.H., and M.W. Adams. 1982. Row width, plant spacing and planting depth. p.
124-133. In L.S. Robertson and RD. Frazier (ed.) Dry bean production- principles &
practices. Michigan State Univ. Coop. Ext. Serv. Bull. E-1251.

Eshel, Y. 1969. Phytotoxicity, leachability, and site of uptake of 2-chloro-2,6-diethyl-N-
(methoxymethyl) acetanilide. Weed Sci. l7(4):441-444.

Evanylo, GK, and HP. Wilson. 1988. Common ragweed in snap beans. Abstr. Proc.
Northeast. Weed Sci. Soc. 42:209.

Field, R]. and S. Nkumbula 1986. Green beans (Phaseolus vulgaris cv. Gallatin 50): Effects
of plant population and density on yield and quality. New Zealand J. Exp. Agric. 14:435-442.

Gerber, H.R., G. Muller and L. Ebner. 1974. CGA 24705, a new grass killer herbicide. Roac.
12th Br. Weed Control Conf. 3:787-794.

Goulden, D.S. 1976. Effect of plant population and row spacing on yield and components
of yield in navy beans (Phaseolus vulgaris). New .Zealand J. Exp. Agric. 4: 177-180.

Hall, M.R., C.J. Swanton, and G.W. Anderson. 1992. The critical period of weed control in
grain corn (Zea mays). Weed Sci. 40:441-447.

Hamill, A.S., L.W. Smith, and CM. Seitzer. 1972. Inﬂuence of phenoxy herbicides on
piclorarn uptake and phytoxicity. Weed Sci. 20:226-229.

19

Jones, R.E., Jr., P.A. Banks, and DE. Radcliffe. 1990. Alachlor and metribuzin movement
and dissipation in a soil proﬁle as inﬂuenced by soil surface condition. Weed Sci.
38:589-597.

Kotoula-Syke, E., K.K. Hatzios, D.F. Berry, and HP. Wilson. 1997. Degradation of
acetanilide herbicides in history and nonhistory soils from eastern Virginia. Weed Techno].
11:403-409.

Lamey, H.A., R.K. Zollinger, D.K. McBride, R.C. Venette, and JR. Venette. 1991.
Production problems and practices of northwest dry bean growers in 1989. North Dakota
Farm Res. 49(2):]7-24.

Leep, R.H., W.F. Meggitt, and M.H. Erdmann. 1982. Weed Control. p. 152-157. In L.S.
Robertson and RD. Frazier (ed.) Dry bean production- principles & practices. Michigan
State Univ. Coop. Ext. Serv. Bull. E-1251.

Malik, V.S., C.J. Swanton, and TE. Michaels. 1993. Interaction of white bean (Phaseolus
vulgaris L.) cultivars, row spacing, and seeding density with annual weeds. Weed Sci.
41:62-68.

Meggitt, W.F. 1977-1985. Weed control guide for ﬁeld crops. Michigan State Univ. Coop.
Ext. Serv. Bull. E-434.

Monks, D.W. and LR. Oliver. 1988. Interactions between soybean (Glycine max) cultivars
and selected weeds. Weed Sci. 36:770-774.

Neary, PE, and BA. Majek. 1990. Common cocklebur (Xanthium strumarium) interference
in snap beans (Phaseolus vulgaris). Weed Techno]. 4:743-748.

O'Donovan, J .T. and RA. O'Sullivan. 1982. The antagonistic action of 2,4-D and bromoxynil
on glyphosate phytotoxicity to barley (Hordeum vulgare). Weed Sci. 30:30-34.

Ogg, AG. and BS. Rogers. 1989. Taxonomy, distribution, biology, and control of black
nightshade (Solanum Nigrum L.) and related species in the United States. Weed Sci.
29:27-32.

Osborne, B.T., D.R. Shaw, and R.L. Ratliff. 1992a, Soybean cultivar tolerance to SAN 582H
and metolachlor as inﬂuenced by soil moisture. Weed Sci. 43:288-292.

Osborne, B.T., D.R. Shaw, R.L. Ratliff, and GP. Ferguson. 1992b. Soybean cultivar

tolerance to SAN 581 and metolachlor as inﬂuenced by soil moisture. Proc. South. Weed Sci.
Soc. 45 :52.

20

Penner D. and D. Graves. 1972. Temperature inﬂuence on herbicide injury to navy beans.
Agron. J. 64:30.

Pillai, P., DE. Davis, and B Truelove. 1979. Effects of metolachlor on germination, growth,
leucine uptake, and protein synthesis. Weed Sci. 27:634-637.

Putnam, AR. and RP. Rice, Jr. 1979. Environmental and edaphic inﬂuences on the
selectivity of alachlor on snap beans (Phaseolus vulgaris). Weed Sci. 27:570-5 74.

Renner, K.A., and 1.]. Kells. 1986-1999. Weed control guide for ﬁeld crops. Michigan State
Univ. Coop. Ext. Serv. Bull. E-434.

Renner, K.A., W.F. Meggitt, and D. Penner. 1988. Response of com (Zea mays) cultivars to
imazaquin. Weed Sci. 36:625-628.

Rhodes, G.N., Jr. and H.D. Coble. 1984. Inﬂuence of bentazon on absorption and
translocation of sethoxydim in goosegrass (Eleusine indica). Weed Sci. 32:595-597.

Rice, R.P., Jr. and AR. Putnam. 1980. Temperature inﬂuences on uptake, translocation, and
metabolism of alachlor in snap beans (Phaseolus vulgaris). Weed Sci. 28(2): 13 1-134.

Robertson, LS. and RD. Frazier (eds). 1978. Dry Bean Production - Principles & Practices.
Michigan State Univ. Ext. Bull. E-1251. East Lansing, U.S.A.

Saxena, A., R. Zhang, and J .M. Bollag. 1987. Microorganisms capable of metabolizing the
herbicide metolachlor. Appl. Environ. Microbiol. 53:390-396.

Selleck, G.W. and DD. Baird. 1981. Antagonism with glyphosate and residual herbicide
combinations. Weed Sci. 29: 1 85-190.

Singh, SP. 1982. A key for identiﬁcation of different growth habits of Phaseolus vulgaris
L. Annual Rpt. Bean Irnprov. Coop. 25:92-96.

Sniper, C.E., J .E. Street, and D.L. Boykin. 1987. Inﬂuence of ﬂood interval and cultivar on
rice (Oryza sativa) tolerance to fenoxaprop. Weed Sci. 35:842-845.

Stephenson, G.R., J .E. McLeod, and SC. Phatak. 1976. Different tolerance of tomato
cultivars to metribuzin. Weed Sci. 24: 161-165.

Todd, B.G. and E.H.Stobbe. 1980. The basis of the antagonistic effect of 2,4-D on
diclofop-methyl toxicity to wild oat (Avenafatua). Weed Sci. 28:371-377.

21

Tripp, TN. and FL. Baldwin. 1988. Effect of excessive precipitation on soybean injury from
imazaquin and chlorimuron. Weed Sci. Soc. Am. Abstr. 28:39.

Verma, RD and R.B.L. Bhardwaj. 1963. Control of farm weeds by use of weedicides. p. 6
New Delhi, Indian Council of Agricultural Research.

Voysest, O. and M. Dessert. 1991. Bean cultivars: classes ad commercial seed types. pp.
119-162. In A. van Schoonhoven & o. Voysest (eds.), Common beans: Research for crop
improvement. C.A.B. Int., Wallingford, U.K. & CIAT, Cali, Colombia.

Wanamarta, G., D. Penner, and J.J. Kells. 1989. The basis of bentazon antagonism on
sethoxydim absorption and activity. Weed Sci. 37:400-404.

Weaver, SE. and CS. Tan. 1983. Critical period of weed interference in transplanted
tomatoes (Lycopersicon esculentum): growth analysis. Weed Sci. 31:476-481.

Weber, J.B. and J .A. Best. 1972. Activity and movement of 13 soil-applied herbicides as
inﬂuenced by soil reaction. Proc. South Weed Sci. Soc. 25:403-413.

Weber, J .B. and C.J. Peter. 1982. Adsorption, bioactivity, and evaluation of soil tests for
alachlor, acetochlor, and metolachlor. Weed Sci. 30:14-20.

Wehtje, G., R. Dickens, J.W. Welcut, and BF. Hajek. 1987. Sorption and mobility of
sulfometuron and imazapyr in ﬁve Alabama soils. Weed Sci. 35:858-864.

Wilson, R.G., Jr., G.A. Wicks, and CR. Fenster. 1980. Weed control in ﬁeld beans
(Phaseolus vulgaris) in Western Nebraska. Weed Sci. 28(3):295-299.

Woolley, B.L., T.E. Michaels, and C.J. Swanton. 1993. The critical period of weed control
in white bean (Phaseolus vulgaris L.). Weed Sci. 41 :180-184.

22

Table 1. Herbicides registered for use on dry beans.

 

 

1979 1999

1. alachlor * l. alachlor

2. triﬂuralin * 2. triﬂuralin

3. EPTC * 3. EPTC

4. bentazon * 4. bentazon

5. dinoseb 5. ethalﬂuralin

6. chlorarnben 6. pendimethalin

7. dinitrarnine 7. metolachlor

8. proﬂuralin 8. dimethenamid
9. imazethapyr
10. sethoxydim
11. clethodim
12. quizalofop-P-ethyl

 

* Herbicides currently registered for use in dry beans

23

Chapter 2

TOLERANCE OF DRY BEAN CLASSES AND CULTIVARS TO
DIMETHENAMID AND METOLACHLOR

KYLE W. POLING

ABSTRACT

Dimethenamid was applied preemergence to 14 dry bean cultivars from the navy,
black, pinto, kidney, cranberry, and small red classes in the greenhouse to determine if there
were differences in tolerance between classes and/or cultivars. Navy and black bean
cultivars were injured from dimethenamid preemergence at 2.1 kg ha". ‘Vista’ and
‘Schooner’ navy beans were injured more than ‘Avanti’ navy bean, and ‘Midnight’ black
bean was injured more than the ‘T-39’ cultivar. Kidney, cranberry, and small red cultivars
were not injured. Kidney and cranberry cultivar emergence was slower (40-42 h) compared
to small seeded cultivars in the navy and black bean classes (27-29 h). In the ﬁeld,
metolachlor at 2.9 kg ha" (twice the recommended rate) and dimethenamid at 1.3 kg ha"
caused similar injury to navy and black bean cultivars.

The F 3 generation of a cross between a ‘Huron’ navy bean and a ‘Matterhorn’ great
northern bean was planted in the ﬁeld to determine whether there was a relationship between
the seed size of dry edible beans and the tolerance of dry beans to dimethenamid.

Dimethenamid at 1.3 kg ha’1 was applied to 98 different F3 lines. The correlation coefﬁcient

24

between seed size and visual leaf area reduction caused by dimethenamid applied
postemergence was signiﬁcant (r=-0.41). This signiﬁcant r value supports the hypothesis
of a negative correlation between seed size and injury resulting from a postemergence

application of dimethenamid.

25

INTRODUCTION

A dry edible bean market class is a category that classiﬁes a dry edible bean
according to size and color of seed. Navy beans are white in color and are considered small
in size (17-22 g/ 100 seeds) relative to other classes of dry beans. Black (or black turtle)
beans, which genetically are closely related to navy beans, are of similar size to navy beans
with a black seed coat. The pinto class of dry beans is tan with dark brown mottling and has
a medium seed size (38-42 g/ 100 seeds). Pinto beans are distantly related to both navy and
black beans. Great northem and pink beans are similar in size and shape to the pinto class
but with a brilliant white and pink seed coat, respectively. The small red or red Mexican
market class is a red bean and is slightly smaller than a pinto bean. The pinto, great northern,
pink and small red market classes are all strongly related genetically. Cranberry dry beans
have a white-red mottled seed coat and are medium-large in size (45-55 g/100 seeds). Light
red and dark red kidney beans are the largest seed of all the market classes (50-60 g/ 100
seeds). The two kidney bean classes and cranberry market class are closely related (Voysest
and Dessert, 1991).

Acreage of each class of dry beans grown can vary dramatically from year to year.
This ﬂuctuation is a direct effect of the price a grower can sell a bag (100 lbs) of dry beans
for in the months preceding planting. Since navy beans and black beans are so well suited
for the climate in Michigan, these market classes account for the majority of dry beans
grown. In 1997 Michigan farmers produced 5,033,000 cwt of dry beans ranking the state as

the second largest producer in the country. Almost half (48%) of the total acres planted in

26

Michigan in 1997 were of the navy bean class and 25% were black beans. The following
year the acres planted in the state declined ﬁ'om 315,000 to 300,000. The number of navy
bean acres accounted for 28% of the total dry beans grown in 1998 while black bean acreage
increased greatly to nearly 42% (Varner, 1991 personal communication).

Differences in herbicide tolerance exist between dry bean market classes and varieties
and vary from one year to the next. In 1993 ‘Fleetwood’ navy bean sustained more injury
from EPTC than ‘Mayﬂower’ navy, ‘Sacramento’ light red kidney, ‘T-39’ and ‘UI-906’
black, ‘Cranberry—74’, and ‘Marquis’ great northern bean (Urwin et al., 1996). The
following year ‘Mayﬂower’ navy, ‘Sacramento’ light red kidney, and ‘Marquis’ great
northern were injured more by EPTC compared to ‘Cranberry-74’ (Urwin et al., 1996). In
other research, imazethapyr was more injurious to the light red kidney cultivar ‘Sacramento’
and pinto cultivar ‘Agate’ in 1988 compared to ‘Beryl’ and ‘GN1140’ great northern or ‘UI
114’ and ‘Olathe’ pinto cultivars (Wilson and Miller, 1991). In 1989 however, injury from
imazethapyr was greater to ‘Olathe’ pinto bean compared with ‘Sacramento’ light red kidney
bean. Bauer et al. (1995) reported greater injury to ‘Olathe’ pinto from imazethapyr
compared to ‘Sierra’ pinto bean.

Objectives important in breeding dry beans are seed yield, maturity for the area of
production, resistance to lodging and shattering, plant architecture, seed quality, tolerance
to stress environments, disease resistance, insect resistance and processing quality (Andersen
and Robertson, 1982). Desirable traits that are controlled by a single gene can be transferred

from one cultivar to another through a succession of backcrosses (Poehlman and Sleper,

27

1995). For traits that are quantitatively inherited, such as lodging resistance, only one or two
backcrosses are performed to combine genes for the desired character into another cultivar
(Poehlman and Sleper, 1995). Irnazethapyr tolerance in pinto bean appears to be a highly
heritable trait, but under quantitative control which suggests that individual plant selection
for tolerance would not be feasible (Bauer et al. 1995).

The objectives of our research were (1) to determine if dry bean classes and/or
cultivars differed in their susceptibility to dimethenamid or metolachlor and (2) to determine

if there was a correlation between seed size and dry bean injury from dimethenamid.

MATERIALS AND METHODS
Greenhouse Study. Dry edible bean tolerance to the herbicide dimethenamid was evaluated
in the greenhouse. The experiment was conducted in a completely randomized design with
four replications and was repeated in time. Dimethenamid was applied at 0 and 2.1 kg ai ha"
to ‘Vista’, ‘Schooner’, ‘Newport’, and ‘Avanti’ navy beans, ‘Bill Z’, ‘Othello’ and
‘Maverick’ pinto beans, ‘T-39’ and Midnight’ black beans, ‘Montcahn’ and ‘California Light
Red’ kidney beans, ‘Michigan Improved’ and ‘Taylor Hort’ cranberry beans, and ‘Rufus’
small red beans. Dry bean seeds were planted at a depth of 2.5 cm in pots containing a
Spinks loamy sand (Psammentic Hapludalfs, sandy, mixed mesic) 86% sand, 10% silt and
4% clay with a pH of 6.5 and 1% organic matter. In a preliminary study twice that of the

recommended rate was needed to induce signiﬁcant visual injury. Dimethenamid was

28

applied at twice the recommended rate determined by soil texture and organic matter to
induce signiﬁcant visual injury (determined in preliminary study).

Injury ratings were recorded at the unifoliate, 1St trifoliate and 3rd trifoliate growth
stages of the dry beans. Injury was determined by visually evaluating dry bean injury on a
scale from 0 (no injury) to 100% (plants were dead). Upon reaching the 3rd trifoliate grth
stage, plants were cut off at the soil surface and leaf area measured with a LI-3000 portable
area meter (LI-COR, Lincohr, Nebraska). The percent leaf area reduction was calculated by
dividing the leaf area of each plant by the mean leaf area of plants from the untreated control
of the same cultivar. Harvested plants were then dried and weights recorded.

Data were subjected to analysis of variance and means separated using Fisher's
protected LSD test at P S 0.05 level of probability. Nontransforrned means are presented
because square root transformation did not alter interpretation of the data. Statistical analysis
revealed no experimental run interactions, so the data were combined and are reported as
means of the two experiments.

Emergence Study. A greenhouse study was conducted to determine the time to emergence
for different classes of dry beans. The same 14 cultivars as listed in the previous study were
evaluated. Dry beans were planted by placing seed horizontally at a depth of 2.5 cm in pots
containing a Spinks loamy sand soil with 1% organic matter and pH of 6.5. The experiment
was arranged in a completely randomized design with four replications and was repeated in

time.

29

Environmental conditions in the greenhouse were maintained at 27 C i 4 C, and
plants were grown in a 16 h photoperiod of natural light supplemented with incandescent
lighting of 1000 uE m'zs“. The time (in h) ﬁom seed planting until the crook stage was
recorded. Plants were evaluated every 12 hours. The hypocotyl diameter was also measured
at the crook stage.

Data were subjected to analysis of variance and means separated using Fisher's
protected LSD test at P g 0.05 level of probability. Nontransformed means are presented
because square root transformation did not alter interpretation of the data. Statistical analysis
revealed no experimental run interactions, so the data were combined and are reported as
means of the two experiments.

Field Screen. A ﬁeld study was conducted at the Saginaw Valley Bean & Sugar Beet
Research Farm in 1998 and 1999 to evaluate the tolerance of navy and black bean cultivars
to dimethenamid and metolachlor. In 1998 the soil at the ﬁeld site was a Misteguay silty
clay loam (Aerie Haplaquept, ﬁne, mixed (calcareous), mesic), 9% sand, 45% silt, and 46%
clay with a pH of 8.0 and 1.9 % organic matter. The soil in 1999 was a Misteguay silty clay
loam (14% sand, 47% silt, and 39% clay) with a pH of 7.8 and 2.6% organic matter. The
ﬁeld was moldboard plowed in the fall prior to the initiation of each study and then tilled
with a ﬁeld cultivator to prepare the seedbed in the spring prior to planting. ‘Vista’,
‘Schooner’, and ‘Newport’ navy beans and ‘Midnight’ and ‘T-39’ black beans were
evaluated. These cultivars are widely grown in Michigan and had shown differential

tolerance to dimethenamid and metolachlor in the greenhouse study.

30

Dry beans were planted in 71 cm rows on June 1 in 1998 and 1999. Plots were four
rows wide by 10 m long. Dirnethenarrrid at 1.3 kg ai ha'1 and 2.6 kg ai ha" and metolachlor
at 2.9 kg ai ha’l were applied to each cultivar. Untreated control plots were included for each
cultivar. Herbicids were applied preemergence with a tractor mounted compressed-air
sprayer with 8003 ﬂat fan spray tips at 177 L ha'1 and 207 kPa. Plots, measuring 2.8 m by
10 m, were organized in a split block design and were replicated three times.

Drybean injury for each variety was measured visually by recording the percent leaf
area reduction at the unifoliate, 1St trifoliate and 3rd trifoliate growth stages. Injury was
measured on a scale of 0 (no leaf area reduction) to 100 (total plant defoliation). In addition
three plants were randomly chosen from the middle two rows of each plot at each evaluation
date, cutoff at the soil surface, and leaf area (cmz) measured with a LI-3000 portable area
meter (LI-COR, Lincoln, Nebraska). Plots were visually evaluated when approximately 66%
of the leaves in the untreated control plots had turned yellow to assess dry bean maturity.
When dry beans reached full maturity, 4.6 m of the middle two rows were hand harvested
and threshed with a stationary thresher. Yields were measured in kg ha’1 and were adjusted
to 18% moisture.

Data were subjected to AN OVA. Visual injury ratings, leaf area, maturity, and yields
were compared within years using Fisher's protected LSD test at P S 0.05. Nontransformed
means are presented because square root transformation did not alter interpretation of the

data. Data is presented separately by years because of a signiﬁcant herbicide by year

3]

interactions. In 1998 there was a variety by herbicide interaction for visual injury ratings,
leaf area measurements, and seed yield so data is presented separately by variety.
F3 Study. A ﬁeld study was conducted to determine the relationship between seed size of
dry edible beans and the tolerance to dimethenamid. Dry beans from the F2 generation of a
cross between a ‘Huron’ navy bean and a ‘Matterhorn’ great northern bean were grown in
the greenhouse. This cross was initially made to breed white mold (Sclerotinia sclerotiorum)
tolerance from the ‘Huron’ cultivar into the ‘Matterhorn’ cultivar. Upon reaching full
maturity seed was harvested from each plant separately. The F2 generation was segregating
thus the offspring (F 3) of different plants had different seed sizes. In our greenhouse research
‘Matterhom’ great northern displayed 10% injury from 2.1 kg ha'l dimethenamid while
injury to ‘Huron’ navy reached 90% 10 DAP (data not presented).

A ﬁeld experiment was conducted in 1999 at the Saginaw Valley Dry Bean and Sugar
Beet Research Farm, Saginaw, Michigan. The soil type was a Misteguay silty clay loam
(14% sand, 47% silt, and 39% clay) with a pH of 7.8 and 2.6% organic matter. The
experimental design was a randomized complete block with two replications. There were
98 different F3 lines in each replication. The parent lines, ‘Huron’ navy beans and
‘Matterhorn’ great northern beans, were included in each replication to compare the
herbicide tolerance in the F3 lines to the tolerance in the parent lines. Plots were one row (56
cm) by 6.1 m. Dimethenamid was applied PRE at 2.6 kg ha", which is twice the
recommended rate, to the plots. Dry beans were not injured from dimethenamid

preemergence due to a lack of rainfall. Therefore, dimethenamid at 1.3 kg ha‘1 was applied

32

POST at the 3"1 trifoliate growth stage. Injury was visually evaluated at 7 and 14 days after
postemergence treatment. When dry beans reached full maturity, each plot was hand
harvested and threshed with a stationary thresher. Seed size (g 100 seed“) was measured for
each plot.

A correlation of the seed size (g 100 seeds") with visual injury that resulted from
dimethenamid postemergence was analyzed using Statistical Analysis System (SAS Institute,

1996). _

RESULTS AND DISCUSSION
Greenhouse Study. Dimethenamid PRE at the 2X rate injured ‘Schooner’ and ‘Vista’ navy
bean cultivars more than it injured the ‘Avanti’ cultivar, when evaluated at the l“ and 3rd
trifoliate grth stages (Table 1). The ‘Bill 2’ pinto and ‘Midnight’ black bean cultivars
were injured more than the other cultivars within the pinto and black bean classes,
respectively (Table 1). The leaf area reduction of ‘Bill 2’ (61 %) was signiﬁcantly greater
than that of the ‘Othello’ and ‘Maverick’ pinto beans at the 3rd trifoliate grth stage. The
leaf area of ‘Midnight’ and ‘T-39’ black beans was reduced by 88 and 52%, respectively,
from dimethenamid PRE. Injury to kidney, cranberry and small red bean was less than 7%
and the reduction in leaf area was not signiﬁcant. A reduction in leaf area could delay
maturity or reduce seed yield since the development of the plants would be reduced while

the dry beans metabolized the herbicide.

33

Emergence Study. Under the conditions of adequate moisture, temperature of 27 C i 4 C,
and 16 h photoperiod ‘Schooner’ and ‘Avanti’ navy bean , as well as the pinto and black
bean cultivars emerged faster in the greenhouse than the kidney, cranberry, and small red
varieties. ‘Califomia Light Red’ kidney had a slower time to emergence (crook stage) than
the ‘Montcalm’ cultivar (Table 2). All other cultivars had similar times to crook stage as
other cultivars within the same dry bean class (Table 2). The time of dry bean emergence
in the greenhouse is similar to the time of emergence in the ﬁeld (Kelly, 1999 personal
cormnunication), although emergence time may vary by seed lot and temperature conditions.
Slower emergence may allow a longer time period for dry bean hypocotyl exposure to
herbicides

The hypocotyl diameters of the kidney and cranberry varieties were signiﬁcantly
greater than the cultivars within the navy, pinto, black, and small red classes (Table 2). If
a dry bean with a small hypocotyl diameter (<29 m) absorbed a similar amount of
herbicide as one with a large hypocotyl diameter (>40 mm), the internal herbicide
concentration would be higher in the dry bean with the small hypocotyl. Increased internal
herbicide concentration could account for greater navy and black bean injury from
dimethenamid and metolachlor.

There was a trend in the time required for emergence to increase as hypocotyl
diameter increased. Navy and black bean varieties with hypocotyl diameters less than 29
mm emerged 83 to 91 h after planting. Kidney and cranberry beans (hypocotyl diameter

greater than 40 mm) reached the crook stage 95 to 105 h after planting.

34

Small seed size may contribute to quicker emergence which would reduce the time

of hypocotyl exposure to herbicide-treated soil. However, the magnitude of difference in
time of emergence was low (22 h) between all dry bean classes. Thus susceptibility of navy
and black beans to dimethenamid and metolachlor may not be related to the length of time
the bean hypocotyl is exposed to herbicide, but may be related to the smaller diameter of the
navy and black bean hypocotyls resulting in an increase in internal concentration.
Field Screen. In 1998 dimethenamid at the 2X rate (2.6 kg ha") caused greater injury to the
‘Vista’, ‘Schooner’, and ‘Avanti’ navy beans and ‘Midnight’ black bean compared with the
1X rate of dimethenamid when evaluated at the 1St trifoliate growth stage (Table 3). There
were no differences in injury to the other cultivars from the two rates of dimethenamid. The
leaf area of ‘Vista’, ‘Schooner’, ‘Newport’, and ‘Midnight’ was signiﬁcantly reduced by
dimethenamid at the 2.6 kg ha'1 rate compared to the untreated control (Table 3). Leaf area
of ‘Newport’ was reduced by dimethenamid at 1.3 kg ha". The injury to the ﬁve dry beans
cultivars from metolachlor at the 2X rate (2.9 kg ha") was similar to that of dimethenamid
at the 1X rate (1.3 kg ha“). Only the leaf area of ‘Newport’ navy bean was reduced by
metolachlor. In 1998 dimethenamid at 2.6 kg ha" delayed maturity of ‘Schooner’ and
‘Newport’ navy bean compared to the untreated control (Table 4). Applications of
dimethenamid or metolachlor did not reduce the seed yield of any of the ﬁve cultivars
compared to the untreated control.

In 1999 there was less injury to dry beans from dimethenamid. Dimethenamid at 2.6

kg ha" was more injurious to all cultivars except ‘Vista’ compared to dimethenamid at 1.3

35

kg ha" (Table 5). Dimethenamid at 1.3 kg ha'1 and metolachlor at 2.9 kg ha'1 caused similar
visual injury to the dry bean cultivars. None of the herbicide applications reduced the leaf
area compared with the untreated control at the 1“ trifoliate growth stage (Table 5).
However, all herbicide applications caused the maturity of the ‘Newport’ cultivar to be
delayed, and dimethenamid at 1.3 and 2.6 kg ha‘1 delayed maturity of ‘Schooner’ navy bean
(Table 5). There were however no differences in seed yield between the untreated control
plots and those treated with herbicide (Table 5).

F3 Study. Dimethenamid PRE did not injure any F 3 line because of limited rainfall from the
time of planting to the 3rd trifoliate growth. Therefore, dimethenamid (1.3 kg ha“) was
applied postemergence to dry beans at the 3rd trifoliate growth stage to determine the
response of the F3 generation. Visual injury 7 days after dimethenamid POST ranged ﬁ'om
15 to 30%. The visual leaf area of the ‘Huron’ navy bean parent line was reduced by 25%
while the leaf area of ‘Matterhorn’ great northern parent line was reduced by only 9%. There
was no visual injury 14 days after dimethenamid postemergence (data not presented). The
correlation coefﬁcient between seed size and visual leaf area reduction caused by
dimethenamid postemergence was negative and signiﬁcant (r = -0.41) (Figure 1). This
supports the hypothesis of a negative correlation between seed size and injury resulting from
dimethenamid POST. However further testing of the F4 generation is warranted to determine

the correlation between seed size and PRE application of dimethenamid.

36

SUMMARY

Navy and black bean cultivars were more susceptible to dimethenamid at the
recommended ﬁeld rate than to metolachlor. Michigan State University recommends
herbicide rates based on soil type (Renner, 1999 personal communication). Cultivars within
the same class of dry beans differed in their tolerance to dimethenamid and metolachlor
(Table 3). No difference in uptake, translocation, or metabolism of dimethenamid between
pinto, navy, and black bean classes has been found (Brunk et al., 1998). The hypocotyl
diameter of dry beans with a large seed size (kidney and cranberry beans) was greater than
that of dry beans with small seeds (navy and black beans). Additionally, dry beans with
large seeds took longer to emerge than dry beans with small seeds. This observation does
not support the hypothesis that small seeded dry beans sustain greater injury since the
hypocotyl was exposed to herbicide-treated soil for a shorter, rather than a longer time period
compared to larger seeded dry beans. However smaller diameters of navy and black bean
may result in an increase in the internal concentration of dimethenamid and result in
decreased dry bean class tolerance. The correlation between seed size and injury to dry
beans from dimethenamid postemergence was negative. Therefore as seed size decreased,
dry bean tolerance decreased also. It would be of interest to determine the relationship of
seed size and herbicide tolerance in the F4 generation with dimethenamid PRE. Decreased
seed size is under control of dry bean class and may be difﬁcult to incorporate into a dry

bean breeding program.

37

LITERATURE CITED

Andersen, AL. and LS. Robertson. 1982. The Michigan dry edible bean industry - History.
p. 1-15. In L.S. Robertson and RD. Frazier (ed.) Dry bean production- principles &
practices. Michigan State Univ. Coop. Ext. Serv. Bull. E-1251.

Bauer, T.A., K.A. Renner, D. Penner, and J .D. Kelly. 1995. Pinto bean (Phaseolus vulgaris)
varietal tolerance to imazethapyr. Weed Sci. 43:417-424.

Brunk, G, L. Randrich, D. Kazarian, P.M. Miller, S. Nissen, and P. Westra 1998. Absorption
and fate of dimethenamid in pinto, black and navy beans. Proc. Western Weed Sci. Soc.
5 l :60.

Poehhnan, J.M. and DA. Sleper. 1995. Breeding soybean. p. 310-311 In Breeding ﬁeld
crops. Iowa State University Press, Ames, IA.

Voysest, O. and M. Dessert. 1991. Bean cultivars: classes ad commercial seed types. pp.

119-162. In A. van Schoonhoven & o. Voysest (eds), Common beans: Research for crop
improvement. C.A.B. Int., Wallingford, U.K. & CIAT, Cali, Colombia.

38

Table 1. Dry bean injury from dimethenamid preemergence at 2.1 kg ha" (twice the
recommended rate).

 

 

 

 

 

 

 

Injury at Leaf Area Reduction
Class Variety 1“ Trifoliate at 3rd Trifoliate
Growth Stage Grth Stage
% %
Navy Vista 26 78
Schooner 29 75
Newport 20 67
Avanti 1 5 50
Pinto Bill Z 19 61
Othello 7 29
Maverick 10 20
Black T-39 1 5 52
Midnight 3 1 88
Kidney Montcahn 6 21
California Light Red 1 13
Cranberry Michigan Improved 2 13
Taylor Hort 5 12
Small Red Rufus 5 17
LSD (PS0.05) 8 —— 25 ——
CV (%) — 58 — —— 59 ——

 

Table 2. Time to emergence and diameter of the hypocotyl at the crook stage of 14
different cultivars of dry beans from six classes.

 

 

 

 

 

 

 

Class Variety Time“ Diameter of Hypocotyl
h —— mm ——

Navy Vista 87 27
Schooner 82 29
Newport 91 27
Avanti 84 27

Pinto Bill Z 85 30
Othello 85 31
Maverick 85 33

Black T-39 85 26
Midnight 83 26

Kidney Montcalm 105 40
California Light Red 96 42

Cranberry Michigan Improved 99 42
Taylor Hort 95 41

Small Red Rufus 94 33

LSD (P5005) 8 3

CV (%) 10 — 8

 

" time from planting to emergence (crook stage) in h.

40

 

 

 

 

 

a S 3.; >0

 

 

 

 

 

 

 

 

 

:. m $3an an

omﬁ o: .2 mi 52 t I I I I BREED
m: am 8 _: m: .2 8 mm 2 M: QN 8202902
3 cm mm no on mm cm on mm mm 9N 28365685
a2 m3 K 53 of E mm om 2 3 m; BEE—05085

NEo .x. 7m: we.
3% E3552 tomaoz cocoonom «85 on? 23:22 20950 Z Cocoonom 52> 8mm oEoBBE
82 «84 En:

 

.wmﬂ E mam commas 33020on 28 22855086 80¢ was—38 03:85 a— 2: 3 no.8 .32 can SE .m 2an

4]

2:668 fow— 2 3333 a
30:9» BEE can 329 35:8 830.53 2: E 828— 65 me $00 boﬁgxoaqm =23, poems—«>0 3:253 we? 39%.: a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

w on ex; >0

«.8 mm 55me 84

NE 0:: 82 32 EN 5 3 cm 8 S 8385
a: N5 RE 38 8M: 8 mm a t. S 2 5202202
RE 32 ex: 28 ae S we 8 mm a 3 Esaeoﬁoea
8M: 52 at: mm: 32 a S 3 a S 2 28205085

.2 me .x. 22 we.
on? EwEE—Z “.8932 cocoonom Sm; mm? EwEEE ton—Bo Z cocoonom 83> Sum @2055:
.22.» Bow been:

 

.wae E 83020on can 225265088 .«0 mcocmgaqm mam wage—.8 22> poem 98 >25me :32 b0 .v 033.

42

 

 

 

 

 

2 8 3e >0

 

 

 

 

 

 

 

 

 

 

mm m Godwe 84

N2 02 m2 mg 53 I I I I I 38825

n: of m3 9: w: I S Q 2 2 ad Siam—202

3; 9: m2 mg m: 2 .2 E E 3 9m 2832585

a: 9: EL mm“ of m E m I o. m._ 25255085
NEu .x. 7m: mx

3.... EwEEE togoz cocoozom 33> mm? EwEEE tomaoz cocoonom Sm; Sum 02038:

52¢. .33 ~96:
.32

E Since—808 wen 2832—386 mo 30:8:QO my; Sow mac—38 omﬁm 53on 08:85 i 05 am «one awo— 98 .635 .m 2an

43

0.80088 X? 8 60803.60 8
30:0» @088 can 08E .8800 80.0088: 05 E 0082 05 we face 3208?“:qu 8055 8000296 3.0503 003 30888 a

 

 

 

 

 

 

 

 

 

 

 

 

 

a. a 3 >0

00m 5 Godwe 80

$3» cog omom 02 m emcm oo .8 me no mm BBEED
meme o E 0v 3% $3 com m on no mm me on ad 8300—202
33 em 3» NM 5 Saw 3.3 mm 3 om mm mm ON 280805085
Emv on? $3 wnmm 08mm on no ow mm on m._ 280805085

23 a. .x. .2 00
mm? EwEEE 8.8950 Z Scoonom 03> mm? EwEEE 80950 Z Scooaom SE> 08m 0EE€0E

 

.20; Bow has“:

.002 E 8200—808 can 28805086 we 80:00:30 mam wEBo=£ E03 0000 8:0 38508 :00: >5 .o 030%

.500 E058: 000% .Eoﬁgmz. 55 000080 500 has .0053. mo @0on mm

05 8 00003080300 00:30 280005086 00013 300 N. 5:262 00.3 .000— _0:m_> 8 0N6 0000 0002500 qucoumﬁm A 0.5mm”—

Amu00m oo :8 0N_0 0000
mm 0m mm om

 

 

 

 

 

 

 

  

 

 

 

_ h _ II.

a

o e

1111 - 11 - - 1 11m m...

-1 14 - 1 - -1 w

k; - 1 - 2 a

J

- 1 1 11- 1E m

11 1.1.11 9 19.11.11: n

o oo 93 0 ON m."

1 1 -1 1010;089:909. '11 mm o

EBB." o o o o m,

1.1.- 1.1.3111- 111. - I om m

mow Nm+x5mmo I

mm

8:: a u .

00:: E039 .EoﬁBﬁE. n ‘ 00:: E008 .552. n I

45

Chapter 3

DRY BEAN RESPONSE TO DIMETHENAMID AND METOLACHLOR
AS INFLUENCED BY TIMING OF APPLICATION

KYLE W. POLING

ABSTRACT

Dimethenamid preemergence at 2.1 kg ha‘1 was more injurious to dry beans than
metolachlor at 2.9 kg ha’1 when evaluated at the 1St and 3rd trifoliate growth stages in the
greenhouse. ‘Othello’ pinto bean was more tolerant to dimethenamid and metolachlor than
cultivars in the black and navy bean classes. There was no difference in injury from PPI
compared to PRE applications of dimethenamid and metolachlor. However injury to ‘Vista’
navy bean was greatest when dimethenamid and metolachlor were available for uptake in
the navy bean hypocotyl compared to the root zone.

In the ﬁeld dimethenamid and metolachlor at the recommended rates caused severe
injury to ‘Vista’ navy bean when applied at the crook or unifoliate grth stages. Early
season injury delayed plant maturity but did not reduce seed yield. Dimethenamid and
metolachlor PPI resulted in 3 to 4% injury to navy beans while these herbicides PRE injured
dry beans 5 to 7%. T ank-mixing dimethenamid at 1.05 kg ha" with bentazon at 0.84 kg ha"
plus dimethoate at 1.12 kg ha" plus COC at 2.34 L ha" caused less injuryto navy bean

compared to than dimethenamid applied alone at the 2“d trifoliate grth stage.

46

INTRODUCTION

Chloroacetamide herbicides are applied in dry beans to control annual grasses,
small-seeded broadleaf weeds, and yellow nutsedge (Cyperus esculentus L.). Deal and Hess
(1980) and others (Anonymous, 1992) have concluded that chloroacetamide herbicides
inhibit both cell division and cell enlargement in plants. Chloroacetamide herbicides
registered for use on dry beans include alachlor
[2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)- acetanilide], metolachlor
[2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl) acetarnide, and dimethenamid
[2-chloro-N—(2,4-dimehtyl-3-thienyl)-N-(2-methoxy-1-methy1ethyl)-acetamide]. These
herbicides are applied preplant incorporated (PPI) or preemergence (PRE), prior to dry bean
emergence (Renner and Kells, 1999).

Metolachlor has become the standard herbicide treatment for preemergence grass
control in dry beans (Renner, 1999 personal communication). In 1996, dimethenamid, a
chloroacetamide herbicide developed for use in corn and soybeans, was granted registration
from the United States Environmental Protection Agency for use in dry beans (Renner and
Kells, 1999). Dimethenamid can cause more injury to soybeans than metolachlor (Osborne
et al., 1992). Dimethenamid injured some dry bean ﬁelds in Michigan in 1996. Injury
occured most often after a preemergence or application at the early crook stage.

The site of chloroacetamide uptake differs in plant species. Metolachlor applied in
the shoot zone of corn (Zea mays) and barley (Hordeum vulgare L.) decreased plant height,
emergence, and dry weight (Pillai et al., 1979). However when metolachlor was applied in
the root or seed zone there was no detectable effect. When metolachlor was applied in all

47

three zones, emergence, height, and dry weight of corn and barley were always reduced
(Pillai et al., 1979). Early uptake of alachlor in snap bean occurred primarily via the shoot
portion of the emerging seedling (Rice and Putnam, 1980). Putnam and Rice (1979)
demonstrated that snap bean injury was lessened when alachlor was applied preplant
incorporated compared with a preemergence surface treatment. An increase in crop safety
was attributed to the reduction of herbicide in the zone of emergence, thus less alachlor was
absorbed by the bean hypocotyl.

Alachlor and metolachlor are not registered for postemergence application in dry
beans. Dimethenamid is registered for postemergence application to dry bean (Anonymous,
1999) but may be injurious to the crop. Injury to dry beans ﬁom postemergence applications
of imazethapyr decreased when bentazon was tank-mixed with imazethapyr (Bauer et al.,
1995). Bentazon decreased absorption and translocation of imazethapyr in pinto beans
(Bauer et. al., 1995).

The objectives of this research were (1) to determine if placement or application
timing of dimethenamid inﬂuenced dry bean tolerance to dimethenamid and (2) to determine
if tank-mixing bentazon with dimethenamid inﬂuenced dry bean response to postemergence

applications of dimethenamid.

MATERIALS AND METHODS
Greenhouse Placement Study. Tolerance of six dry bean cultivars to preplant incorporated
and preemergence dimethenamid and metolachlor was evaluated. Dimethenamid at 2.1 kg
ha‘l and metolachlor at 2.9 kg ha'1 were applied preplant incorporated or preemergence to

48

‘Vista’ and ‘Schooner’ navy beans, ‘Midnight’ and ‘T-39' black beans, and ‘Othello’ and
‘Bill Z’ pinto beans in the greenhouse. Treatments were applied in a factorial arrangement.
All pots were arranged in a completely randomized design. Each treatment was replicated
four times and the experiment was repeated. Untreated controls were included for each
cultivar.

Pots measuring 10 cm in height and 12 cm in diameter were ﬁlled with 7 cm of a
Spinks loamy sand (Psammentic Hapludalfs, sandy, mixed mesic), 86% sand, 10% silt and
4% clay with a pH of 6.5 and 1% organic matter. One seed per pot was placed on top of the
soil. In preparation for the preemergence treatments, additional soil (2.5 cm) was placed
over the seed. The preemergence treatments were then sprayed using an 8001-SS nozzle at
234 L ha'1 and 207 kPa. For the PPI applications, sixteen ﬂats (31 by 61 cm) were ﬁlled with
2.5 cm of the Spinks loamy sand soil. The ﬂats of soil were treated with herbicide. The
herbicide and soil were then mixed together in a bucket to simulate preplant incorporation
of a herbicide in the ﬁeld. The treated soil in each bucket was then placed in the pots to
cover the seed. The remaining pots of each cultivar had 2.5 cm of untreated soil placed over
them. Environmental conditions were maintained at 27 C i 4 C, and plants were grown in
a 16 h photoperiod of natural lighting supplemented with incandescent lighting with PAR
of 1000 uE m”2 5".

Visual injury ratings were recorded at the unifoliate, 1St trifoliate and 3rd trifoliate
growth stages of the dry beans. Plants were then cut off at the soil surface and leaf area
measured with a LI-3000 portable area meter (LI-COR, Lincoln, Nebraska). The percent leaf
area reduction was calculated by dividing the leaf area of each plant by the mean leaf area

49

of plants from the untreated control of the same cultivar. Harvested plants were then dried
and weights recorded.

Data were subjected to analysis of variance. Visual injury ratings, leaf area

reduction, and dry weights were compared using Fisher's protected LSD test at P S 0.05. The
data presented are the combined means over the two runs.
Volatility Study. Dimethenamid volatilization was examined in an experiment conducted
in growth chambers. The study was a completely randomized design and the experiment was
repeated two times. Two separate growth chambers were used in the experiment and were
the experimental units.

‘Vista’ navy beans were planted in pots at a depth of 2.5 cm in a Spinks loamy sand
soil (86% sand, 10% silt and 4% clay) with a pH of 6.5 and 1% organic matter. Plants were
grown in growth chambers with a 16 h phototoperiod at 28 C day / 17 C night temperature
regime with 85% relative humidity. When the navy beans reached the crook grth stage,
ﬁve randomly selected pots were removed from one of the growth chambers. Dimethenamid
at 2.1 kg ha‘1 was applied to these pots as previously described and the pots were
immediately returned to the growth chamber. The other growth chamber was the untreated
control and did not contain any dimethenamid treatments.

Data were subjected to analysis of variance and means separated using Fisher's
protected LSD test at P _<_ 0.05 level of probability. Nontransformed means are presented
because square root transformation did not alter interpretation of the data. Statistical analysis
revealed no experimental run interactions, so the data were combined and are reported as
means of the two experiments.

50

Site of Uptake Experiment. An experiment was conducted in the greenhouse to determine
if the hypocotyl, seed, or roots of ‘Vista’ navy beans preferentially absorbed dimethenamid
and metolachlor. The experiment was a completely randomized design arranged as a
two-factor factorial with four replications and was repeated in time. Sites of herbicide uptake
included the hypocotyl, seed, root, hypocotyl + seed, and root + seed. A charcoal barrier
method similar to that employed by Gray and Weieiich (1969) was used to prevent the
movement of herbicide in the soil in order to expose only the hypocotyl, root, or seed zones
in the various treatments.

An application rate eight times the recommended rate was needed for visual injury
to occur. This excessive rate of herbicide was needed because any herbicide coming into
contact with the charcoal layer was absorbed and not available for uptake by the dry beans.
Dimethenamid at 8.4 kg ha" and metolachlor at 11.4 kg ha" were applied to ﬂats of soil (2.5
cm) as described previously. Soil was then placed in a bucket and mixed thoroughly to
incorporate the herbicide into the soil.

Different models with various arrangements of charcoal barrier(s) were used to
evaluate the uptake of herbicide by the hypocotyl, seed, and roots alone, as well as the
hypocotyl plus seed and root plus seed zones (Figure 1). In all models the seed was placed
at a depth of 4 cm. To expose only the dry bean hypocotyl to herbicide, 5.5 cm of a Spinks
loamy sand soil (86% sand, 10% silt and 4% clay) with a pH of 6.5 and 1% organic matter
was placed in the bottom of a pot measuring 9 cm in height. One seed was placed at a depth

of 1 cm into the untreated soil. A 0.5 cm layer of a mixture (1:1, v/v) of powdered activated

51

charcoal and moist untreated soil was added and leveled. Herbicide-treated soil (2.5 cm) was
placed above the charcoal layer and leveled (Figure 1a).

For root exposure (Figure lb), 2.5 cm of herbicide-treated soil was placed in the
bottom of a pot followed by a charcoal barrier (0.5 cm). Untreated soil (5.5 cm) was placed
on top of the charcoal barrier. For exposing the seeds, the layers from top to bottom were;
2.5 cm untreated soil, 0.5 cm charcoal, 2.5 cm of soil containing the seeds, 0.5 cm charcoal,
and 2.5 cm untreated soil (Figure 1c). For seed plus root exposure (Figure 1d) the charcoal
and soil arrangement were as follows: 2.5 cm of herbicide treated soil was placed on the
bottom the pot, 2.5 cm of untreated soil containing the seed, 0.5 cm charcoal, and 2.5 cm
untreated soil. To expose hypocotyl plus seed parts, the above procedure was repeated with
the charcoal layer (0.5 cm) located 2.5 cm from the bottom of the pot and the treated soil
being placed in the top of the pot (Figure 1e). An untreated control was included for each
charcoal model. Pots were alternately surface and subsurface watered every day to maintain
moisture and reduce the herbicide adsorption by the charcoal layer(s).

Leaf area reduction was visually evaluated at the unifoliate, lSt trifoliate and 3rd
trifoliate grth stages. After the 3rd trifoliate rating, all plants were cut off at the soil
surface. The total leaf area of each plant was measured using a LI-3000 portable area meter
(LI-COR, Lincoln, Nebraska). The percent leaf area reduction was calculated by dividing
the leaf area of each plant receiving a herbicide treatment by the mean leaf area of the plants
from the respective untreated control (same location of charcoal barriers). The harvested

leaves and stems from each plant were then dried and weights recorded.

52

Data were subjected to analysis of variance and means separated using Fisher's

protected LSD test at P _<_ 0.05 level of probability. Nontransformed means are presented
because square root transformation did not alter interpretation of the data. Statistical analysis
revealed no experimental run interactions, so the data were combined and are reported as
means of the two experiments.
Timing of Application Study. Dry bean tolerance to dimethenamid and metolachlor
applied at various timings was determined in a ﬁeld study in 1998 and 1999. The ground
was tilled twice with a ﬁeld cultivator prior to planting to remove weeds and prepare the
seedbed. ‘Vista’ navy bean, a 98 day maturity bean, was planted at a population of 272,000
seeds ha‘I in 76 cm rows. The navy beans were planted on June 2, 1998 and June 4, 1999.
The soil type in 1998 was a Capac loam (Aeric Ochraqualfs, ﬁne-loamy, mixed mesic), 45%
sand, 37% silt and 18% clay with a pH of 7.8 and 2.4% organic matter. In 1999, the soil was
a Capac sandy loam (52% sand, 34% silt and 14% clay) with a pH of 7.1 and 2.5% organic
matter.

Plots were 3 m wide (four rows) by 9.1 m in length. Fourteen treatments were
replicated four times in a randomized complete block design with a two factor factorial
arrangement of treatments. The factors were two herbicides and six application timings.
Dimethenamid (1.3 kg ha“) and metolachlor (1.4 kg ha“) were each applied preplant
incorporated (PPI), preemergence (PRE), and at the early crook stage, unifoliate, 1St trifoliate
and 2"d trifoliate growth stages. An untreated control for each herbicide was included in each
block. Plots were maintained weed-free for the entire season to eliminate the confounding
factor of weed interference on navy bean maturity and yield.

53

Plots receiving a herbicide treatment were visually compared to the untreated plots
in their respective block. Visual leaf area reduction was evaluated at the unifoliate, 1“
trifoliate and 3rd trifoliate growth stages. Postemergence applications were also rated
visually for leaf area reduction 3, 7, and 14 days after treatment. All plots were evaluated
35 days after planting for visual leaf area reduction. Visual maturity ratings were taken by
recording the percent leaf yellowing when approximately two-thirds of the leaves in the
untreated control plots had turned yellow. The middle two rows of each plot were harvested
with a self-propelled combine and yield adjusted to kg ha'1 at 18 % moisture.

Visual estimates of leaf area reduction were arcsine transformed prior to statistical

analysis and subjected to AN OVA procedures. Means of the transfonned leaf area reduction
data , maturity, and yields were separated using Fisher's protected LSD test at P 5 0.05 level
of probability. Nontransformed data are presented for clarity. Statistical analysis revealed
no experimental run interactions, so the data were combined and are reported as means of
the two experiments.
Dimethenamid / S—dimethenamid. The tolerance of dry edible beans to dimethenamid and
S-dimethenamid was evaluated in 1998 and 1999. In 1998 the soil was a Capac loam (45%
sand, 37% silt and 18% clay) with a pH of 7.8 and 2.4% organic matter. In 1999 the soil was
a Capac loam (50% sand, 31% silt and 19% clay) with a pH of 7.2 and 2.3% organic matter.
Plots were maintained weed-free the entire season to eliminate the confounding factor of
weed interference on navy bean maturity and yield.

The seedbed was prepared with two passes of a Danish S-tine ﬁeld cultivator in the
spring of both years. ‘Schooner’ navy beans were planted on June 2, 1998 and June 4, 1999

54

at a population of 272,000 seeds ha'1 in plots measuring 3 m by 9.1 m with a crop row
spacing of 76 cm.

Dimethenamid at 1.3 and 2.6 kg ha'1 and S-dirnethenamid at 0.72 and 1.44 kg ha’1
were applied PRE or at the 1“ trifoliate growth stage. Leaf area reduction was visually rated
at the unifoliate, 1St trifoliate and 3rd trifoliate stages. Leaf area reduction was also evaluated
at 3, 7, and 14 days after the 1“ trifoliate growth stage application and all plots were also
evaluated 35 days after planting. To estimate relative maturity the percent leaf yellowing
was recorded when two-thirds of the leaves in the control plot had yellowed. The middle
two rows of each plot were harvested with a self-propelled combine. Seed yield was
adjusted to kg ha'1 at 18% moisture.

Data were subjected to analysis of variance and means separated using Fisher's
protected LSD test at P S 0.05 level of probability. Nontransformed means are presented
because square root transformation did not alter interpretation of the data. Data is presented
separately by years because of a signiﬁcant herbicide by timing by year interaction.
Postemergence Application of Basagran Plus Dimethenamid. A ﬁeld study in 1998 and
1999 was conducted to determine dry bean tolerance to dimethenamid in the presence and
absence of bentazon and/or dimethoate insecticide. Treatments included 0.84 kg ha’1
bentazon, 1.05 kg ha" dimethenamid, 1.12 kg ha'l dimethoate, and 2.34 L ha‘I crop oil
concentrate (COC).

The seedbed was prepared each year with fall moldboard plowing followed by two
applications with a Danish S-tine ﬁeld cultivator in the spring. ‘Vista’ navy beans were
planted on June 1, 1998 and June 3, 1999. The soil type in 1998 was a Misteguay silty clay

55

loam (Aerie Haplaquept, ﬁne, mixed (calcareous), mesic), 9% sand, 45% silt, and 46% clay
with a pH of 8.0 and 1.9% organic matter. In 1999 the soil was a Misteguay silty clay loam
(14% sand, 47% silt, and 39% clay) with a pH of 7.8 and 2.6% organic matter. Navy beans
were planted in 2.8 m by 5.6 m plots with row spacing of 72 cm at a population of 272,000
seeds ha‘1 in both years.

Treatments were applied at either the 1St trifoliate or 2“d trifoliate grth stage of the
dry beans. An untreated control plot was included for comparison at each application timing.
Plots were rated visually for leaf area reduction at 3, 7, and 14 days after treatment. Visual
maturity ratings were measured by recording percent leaf yellowing when two-thirds of the
leaves in the untreated control were yellow. The middle two rows of each plot were
harvested with a self-propelled combine and seed yield was converted to kg ha‘1 at 18%
moisture.

Treatments were replicated four times in a split plot design with the main plot
application timing and the subplot the pesticide treatments. Visual estimates of leaf area
reduction were subjected to square root transformation transformed prior to statistical
analysis and subjected to AN OVA procedures. Means of the transformed leaf area reduction
data, maturity, and yields were separated using Fisher's protected LSD test at P _<_ 0.05 level

of probability. Nontransformed data are presented for clarity.

RESULTS AND DISCUSSION
Greenhouse Placement Study. Plants were stunted and leaf area reduced by dimethenamid
and metolachlor applied PPI or PRE. There were no signiﬁcant difference in injury from PPI

56

compared to PRE applications when evaluated at the l" or 3" trifoliate growth stage (Table
1). Dry beans at the unifoliate and l" trifoliate growth stages grew more rapidly and
trifoliate leaves emerged faster when treated with a herbicide compared with plants that did
not receive a herbicide application (data not presented).

Dimethenamid caused greater injury than metolachlor when evaluated at the 1"
trifoliate and 3rd trifoliate grth stages (Table 1). Dry weights however were similar for
dimethenamid and metolachlor because 80 % of the dry weight consisted of the stem weight
while only a minimal percent of the weight was from the leaves (data not presented).

Dry bean varieties differed in their tolerance to dimethenamid and metolachlor.
‘Othello’ pinto bean was more tolerant than the black and navy bean cultivars (Table 1).
‘Midnight’ and ‘T-39’ black beans did not differ in tolerance to these chloroacetamide
herbicides, nor did ‘Vista’ navy bean tolerance differ from that of ‘Schooner’ navy bean.
‘Schooner’ navy bean leaf area was reduced at the 3rd trifoliate growth stage compared with
leaf area of ‘Midnight’ black bean and the pinto cultivars (Table 1).

Our research results concur with Kazarian et al. (1999) where navy and black beans
showed greater sensitivity to dimethenamid, S-dimethenamid, and metolachlor compare to
pinto beans. Our data indicated dimethenamid to be more injurious than metolachlor.
Research in soybean has shown that the magnitude of soybean injury is often greater from
dimethenamid compared to metolachlor (Osborne et al., 1992b). The injury that
dimethenamid and metolachlor caused to the dry beans did not differ from PPI compared

with PRE applications on the same cultivar. Our research did not concur with Putnam and

57

Rice (1979) where snap bean injury decreased when alachlor was preplant incorporated
compared with a preemergence surface treatment.

Volatility Study. Only dry beans treated with dimethenamid showed injury symptoms (data
not presented). Some dry bean growers have attributed the injury caused by dimethenamid
from PPI or PRE applications to volatilization of the herbicide. This research conducted in
the growth chambers does not support this hypothesis because dimethenamid injury was only
apparent on dry beans that were treated with dimethenamid at the crook stage of growth.
Dimethenamid has a 100-fold lower vapor pressure (2.76 x 10" mm Hg at 25 C) compared
to EPTC (S-ethyl dipropylthiocarbarnate) (3.4 x 10'2 mm Hg at 25 C), a herbicide known to
readily volatilize (Weed Science Society of America, 1994).

Site of Uptake Experiment. Chloroacetarnides caused the greatest injury and leaf area
reduction when placed in the hypocotyl plus seed zone (Table 2). Dry bean injury was
negligible when herbicide was placed in the seed zone, followed by placement only in the
root zone (Table 2). In previous research Rice and Putnam (1980) found early uptake of
alachlor in snap bean occurred primarily via the hypocotyl portion of the emerging seedling.
Snap bean tolerance increased when the amount of alachlor in the zone of emergence was
reduced, thus less alachlor was absorbed by the bean hypocotyl (Rice and Putnam, 1980).
Therefore, placement of dimethenamid or metolachlor in the upper 3 cm of the soil proﬁle
may increase dry bean response to these chloroacetamide herbicides because of hypocotyl
exposure to the concentrated herbicide area.

Timing of Application Study. Dimethenamid and metolachlor caused more injury to dry
beans when applied at the crook or unifoliate grth stages compared with PPI, PRE, or

58

postemergence applications at the 1" and 2 “6 trifoliate growth stages (Table 3).
Dimethenamid at the unifoliate growth stage caused greater leaf area reduction of ‘Vista’
navy bean compared to metolachlor (Table 3). However evaluation of leaf area reduction
at the 3"1 trifoliate stage showed similar response of navy bean to dimethenamid and
metolachlor applied at the crook and 1“ trifoliate grth stages (Table 3).

Dimethenamid and metolachlor PPI caused less leaf area reduction compared with
PRE applications however the relative difference was small. Putnam and Rice (1979)
demonstrated that snap bean injury decreased when alachlor was applied preplant
incorporated compared to a preemergence surface treatment and our site of uptake research
also supports more potential injury from PRE applications. However, in our greenhouse
study (Table 1) there was no difference in bean response to PPI and PRE applications.
Possibly the pots and 10 cm soil depth in the greenhouse allowed herbicide to remain
available for uptake regardless of the application method.

The early season injury caused by applications of dimethenamid at the crook and
unifoliate stages delayed physiological maturity compared with the untreated control (Table
3). Dimethenamid at the rmifoliate stage delayed maturity by 27% compared to the untreated
control. Metolachlor caused a delay in maturity only when applied at the unifoliate growth
stage. This delay in maturity of dry beans following early season injury has been reported
for applications of imazethapyr on pinto, great northern, and light red kidney beans (Bauer
et al., 1995; Wilson and Miller, 1991). Dimethenamid applied at the unifoliate stage reduced
seed yield compared to the untreated control. Irnazethapyr did not always reduce seed yield
even when maturity was delayed (Bauer et al., 1995; Wilson and Miller, 1991).

59

Dimethenamid / S-dimethenamid. There was no difference in injury from dimethenamid
and S-dimethenamid at similar rates and application timings (Table 4). In 1998 and 1999,
preemergence applications of dimethenamid and S-dimethenamid at 2.6 and 1.4 kg ha'1
(twice the suggested application rate for this soil type), respectively, were signiﬁcantly more
injurious than applications at 1.3 and 0.7 kg ha", respectively (Table 4). There were no
differences in dry bean injury from applications of dimethenamid or S-dimethenamid at the
recommended ﬁeld rate compared with the 2X rate when applied at the 1" trifoliate growth
stage in 1998 (Table 4). However, in 1999 dimethenamid or S-dimethenamid applied at the
2X rate injured the navy beans signiﬁcantly more than the herbicides applied at the 1X rates
(Table 4). Injury following PRE herbicides in 1998 was greater than applications at the l"
trifoliate growth stage (Table 4). In 1998, when the dry beans were just emerging ﬁ'om the
soil, 0.94 cm of precipitation was received. Putnam and Rice (1979) reported that injury to
snap bean corresponded with heavy rainfall and warm temperature during and immediately
after germination. In 1999 dimethenamid and S-dimethenamid applied PRE resulted in only
minimal injury (Table 4). It did not rain from the time of planting until the dry beans
emerged from the soil in 1999. S-dimethenamid is an isomer of dimethenamid (John Balles,
BASF, personal communication). An isomer is a chemical whose molecules contain the
same number and kind of atoms as another chemical but are arranged differently. The crop
response to soil-applied treatments of dimethenamid and S-dimethenamid should be similar
(John Balles, BASF, personal communication). Dimethenamid and S-dimethenamid applied
PRE did not delay physiological maturity in 1998 (Table 4). However, in 1998
dimethenamid at the 2X rate applied at the 15' trifoliate grth stage delayed maturity more

60

than S-dimethenamid at the 2X rate applied at the same time (Table 4). The early season
injury of the dry beans did not result in a maturity delay in 1999 (Table 4).

Dry bean response to dimethenamid postemergence has not been reported previously,

nor has information on the S—dimethenamid formulation. Isomers of metolachlor have not
resulted in weed control or crop response differences (Renner and Kells, 1999) and our
research suggest that dry bean tolerance to S-dimethenamid will be similar to dry bean
tolerance to dimethenamid. In 1998 and 1999 there were no differences in seed yield
between plots receiving an application of dimethenamid or S-dimethenamid PRE or at the
15' trifoliate stage, with the exception of dimethenamid applied PRE at the 1X rate in 1998
(Table 4).
Postemergence Application of Basagran Plus Dimethenamid. Injury for all treatments
was minimal (510%) (Table 5). The addition of bentazon to dimethenamid and
dimethenamid + COC applied at the 1" trifoliate growth stage did not inﬂuence crop injury.
However, the addition of bentazon to dimethenamid + dimethoate + COC at the 1“' trifoliate
grth stage increased crop injury (Table 5). At the 2"d trifoliate growth stage, the addition
of bentazon to dimethenamid and dimethenamid + COC reduced crop injury. However
bentazon did not reduce crop response to dimethenamid + dimetheoate + COC at the 2“d
trifoliate growth stage. Temperature at the time of treatment at the 1“ trifoliate was 8 C
higher in 1998 and 2 C higher in 1999 compared with the temperature at the 2"d trifoliate
timing.

Bentazon decreased dry bean injury from dimethenamid in all tank-mixtures except
for dimethenamid + bentazon + dimethoate + COC at the 2"d trifoliate application timing

61

(Table 5). All plots matured at the same rate with no differences observed between the
treated plots and the untreated control (data not presented). Dry bean yields from treated
plots were not signiﬁcantly different from yield of the untreated control in 1998 and 1999
(Table 5). In our study bentazon reduced dry bean injury from dimethenamid and
dimethenamid + COC at the 2“d trifoliate grth stage, however injury was minimal from
all treatments and the addition of bentazon would be economically justiﬁed in this study only

if bentazon was needed for weed control.

SUMMARY

Applications of dimethenamid and metolachlor at the recommended rate can cause
injury to dry beans. Similar to the ﬁndings of Osborne et a1. (1992) in soybeans, the
magnitude of injury in dry beans is oﬁen greater with dimethenamid compared with
metolachlor. There was no difference in injury to dry beans between dimethenamid or
metolachlor applied preemergence and preplant incorporated in the greenhouse. However,
in our research, injury to ‘Vista’ navy beans was greatest when dimethenamid or metolachlor
was available in the hypocotyl zone rather than the root zone. Therefore a concentrated layer
of herbicide in the hypocotyl zone could increase the potential for injury from these
herbicides applied PRE. In our ﬁeld research dimethenamid or metolachlor PRE caused
more injury than dimethenamid or metolachlor PPI. Injury to dry beans from dimethenamid
and metolachlor reduced leaf area early in the growing season. Visual injury and leaf area
reduction also resulted in delayed maturity but did not reduce seed yield. To minimize the
chance of severe injury these herbicides should not be applied at the crook or unifoliate

62

growth stages. Dimethenamid postemergence at the 18' trifoliate growth stage reduced leaf
area ﬁ'om 0 to 21% when measured at the 3rd trifoliate grth stage (Tables 3 and 4),
depending on the site and year. This difference in injury from dimethenamid postemergence
at 1St trifoliate stage suggests that delaying application to the 2"d trifoliate stage may reduce
the potential for leaf area reduction. Maturity was never delayed, nor seed yield reduced
from dimethenamid applied at the 2“d trifoliate stage (Table 3, 4, and 5). Tank-mixing with
bentazon reduced dry bean injury from dimethenamid or dimethenamid + COC and may be
suggested when a postemergence application needs to be made at the 2'“d trifoliate stage of

dry beans because weeds are at the recommended height for herbicide application.

63

LITERATURE CITED

Anonymous. 1992. SAN 582G experimental herbicide: A technical overview. Sandoz Agro,
Inc., Des Plaines, IL 60018.

Anonymous. 1999. Frontier 6.0 herbicide product label. BASF Corp., Agricultural Products,
Research Triangle Park, NC 27709.

Bauer, T.A., K.A. Renner, and D. Penner. 1995. ‘Olathe’ pinto bean (Phaseolus vulgaris)
response to postemergence imazethapyr and bentazon. Weed Sci 43:276-282.

Deal, L.M. and FD. Hess. 1980. An analysis of the growth inhibitory characteristics of
alachlor and metolachlor. Weed Sci. 28:168-175.

Kazarian, D., P.M. Miller, S. Nissen, and P. Westra. 1998. Dry edible bean response to shoot
and foliar applications if dimethenamid, BAS 656, and metolachlor. Proc. Western Weed
Sci. Soc. 51:60.

Osborne, B.T., D.R. Shaw, and R.L. Ratliff. 1992. Soybean cultivar tolerance to SAN 582H
and metolachlor as inﬂuenced by soil moisture. Weed Sci. 43:288-292.

Pillai, P., DE. Davis, and B Truelove. 1979. Effects of metolachlor on germination, growth,
leucine uptake, and protein synthesis. Weed Sci. 27:634-637.

Putnam, AR. and RP. Rice, Jr. 1979. Environmental and edaphic inﬂuences on the
selectivity of alachlor on snap beans (Phaseolus vulgaris). Weed Sci. 27:570-574.

Renner, K.A., and J .J . Kells. 2000. Weed control guide for ﬁeld crops. Michigan State Univ.
Coop. Ext. Serv. Bull. E-434.

Rice, R.P., Jr. and AR. Putnam. 1980. Temperature inﬂuences on uptake, translocation, and
metabolism of alachlor in snap beans (Phaseolus vulgaris). Weed Sci. 28(2):131-134.

Weed Science Society of America. 1994. Pages 119-121 and 264-266 in Herbicide
Handbook, seventh edition. Weed Sci. Soc. Am., Champaign, IL.

Wilson, R.G. and SD. Miller. 1991. Dry edible bean (Phaseolus vulgaris) response to
imazethapyr. Weed Technol. 5:22-26.

64

Table 1. Response of six dry bean cultivars to preplant incorporated and preemergence
dimethenamid and metolachlor in the greenhouse.

 

Leaf area reduction at

 

 

 

 

 

 

 

 

 

 

 

 

 

Variable 1" trifoliate injury 3rd trifoliate grth stage
% %
Application method
PRE 12 a 32 a
PPI 11 a 32 a
CV (%) 65 63
Herbicide
Dimethenamid 15 a 40 a
Metolachlor 8 b 25 b
CV (%) 65 63
Cultivar (class)
Vista (navy) 15 a 37 ab
Schooner (navy) 14 a 42 a
T-39 (black) 11 ab 35 ab
Midnight (black) 12 ab 27 b
Bill Z (pinto) 9 bc 27 b
Othello (pinto) 7 c 12 c
CV (%) 65 63

 

 

 

 

 

65

Table 2. Effect of exposing different parts of dry bean seedlings to dimethenamid and
metolachlor-treated soil using charcoal barriers to prevent movement of the herbicide.

 

 

 

 

 

Visual leaf area reduction Leaf area reduction

Site of Uptake at 1" trifoliate stage at 3rd trifoliate stage
% %

Root 28 c 24 cd
Hypocotyl 63 b 53 b
Seed 18 c 8 (1
Root + Seed 32 c 32 c
Hypocotyl + Seed 86 a 84 a
CV (%) — 67 — — 80 —

 

66

.0030: 08 03. 0850000 3 8202205
0:0 280005086 8 8000 be Mo 08898 8.“ :8 00800020500: 05 £8 08005:: £0.3— Eogﬁo .8 :oEwom ._ 08me

 

 

 

 

 

 

     

 

i=8 0000 .0

6000 + _bonuon»: .0 $18 088 .n
00.3: End-BED.

@000 + 088 .0 .38 380an .0

”zﬁwtﬁmr

 

67

055088 {of 9 00505.80
30:0» 0085 00: 088 8580 0050058 05 8 m0>00_ 05.8 $00 3050808800 5053 005020.50 3.0503 003 b55508 a

a

 

 

 

 

0 3 mm 3.0 >0
050 KS 50 w 5m m0 me o .5 o 0050085
50 Sam 050 mﬁwm 00 G n 0 0 50:55. EN
0 muov 050 we? 0m 0m 2 0 0 _ 0508.55. .m—
050 03m 0 Gmm 00 0m 0m 0 0m 0508.502
50 exam 05 mwom hm 5. on 0 K 880
050 wvwm 05 cmnm 00 mm m 0 h mam
50 exam 050 $3 8 E m 0 v in
100: we. i 1 838:0» .x. X.
83008508 080505080 82007508 080505080 82008508 280805080 w88E. 85008.5

 

 

 

00—0; 000m

.0030: 0202830

GOUOSUOM 602 Mao..— OHQSOmCr—r Em

 

.002 000 M33 8 8005 .90: .0503. 8 83008508 050 280505080 8 8500580 .8 885 .8 80km .m 030%

68

0506.: few— 8 00003.00 0
26:0: 0085 00: $2: 3980 00000000: 2: E m0>00_ 05 :0 $00 3000808030 00:? 0000205 b380, 003 39:08 a

 

 

 

 

 

 

 

Isl Ial Iﬁl |0l Imml Ial £36
a can 00 :30 m: wm 3 8 0 a 0 mm 00085: 3

2 88 00 Sam 2 mm m E 3 2 o a 20:05.: .3 200550500
8 83 as 3% a S B 3 0 Q o om 200.05.: 0.0

a a? ﬁ 33 a 00 00 S 0 cm 0 om 20:00.; 2 20055080
2 83 0 no: 2 mm B 8 B M: 0 8 000 E

a 20m 00 03m 8 mm a E o S 0 mm B: 8 2.5550800
a :5. 0 gm 2 mm o No 0 _m a 8 000 00

a a; 0 008 2 mm a 2. o 2 0 3 my: 2 25055050

70: w: l wage—.0» .x. c\° I 70: wx I
32 02: 82 09: 32 82 0:05 000 020550
.00; 0000 Eva“: 020220.30 0:? 20:00: am 8080090

 

dam: 0:0 M32 5 0:00: ~90: magnum.
so 0wﬁm :thw 80:85 a: 05 00 0:0 man 03:50 00:3 050000500000 000 0000005250 mo 000:0o:&0 :0 0000.5 .0 030B

69

Table 5. ‘Vista’ navy bean injury and yield following application of various tank-mixtures
of dimethenamid, bentazon, dimethoate, and crop oil concentrate (COC)a at the 1St and 2“d
trifoliate growth stages combined over 1998 and 1999.

 

 

 

 

 

Injury 7 DAPO Seed Yield
1St trifoliate 2nd trifoliate 1St trifoliate 2“d trifoliate
Treatments application application application application
% —— g ha'l

dimethenamid 1 g 9 b 2884 abc 2879 abc
dimethenamid + COC 2 f 10 a 2949 abc 2817 abc
bentazon + COC 1 g 4 e 3070 ac 2933 abc
dimethenamid + bentazon 1 g 5 d 2787 bc 2799 c
dimethenamid + bentazon + 2 f 5 d 2804 bc 2791 c
COC
dimethoate 0 h 1 g 2904 abc 2970 abc
dimethenamid + dimethoate 2 f 7 c 2886 abc 2755 c
dimethenamid + dimethoate 2 f 10 a 2967 abc 2858 abc
+ COC
dimethenamid + bentazon + 1 g 5 d 2933 abc 2834 abc
COC
dimethenamid + bentazon + 7 c 9 b 2849 abc 2758 c
dimethoate + COC
bentazon 0 h 1 g 283 1 abc 3021 ab
untreated 0 h 0 h 2848 abc 2996 abc
CV (%) —— 55 9

 

 

 

aHerbicide rates: 0.84 kg ha'1 bentazon, 1.05 kg ha'l dimethenamid, 1.12 kg ha'1
dimethoate, and 2.34 kg ha'l crop oil concentrate (COC)

7O

Chapter 4
INFLUENCE OF ENVIRONMENTAL CONDITIONS AT THE TIME OF
PLANTING AND EMERGENCE ON DRY BEAN TOLERANCE
TO DIMETHENAMID AND METOLACHLOR

KYLE W. POLING

ABSTRACT

‘Vista’ and ‘Schooner’ navy bean cultivars were planted on ﬁve dates in 1998 and
1999 to determine the inﬂuence of planting date on dry bean response to dimethenamid and
metolachlor. Dimethenamid at 2.3 kg ha'l and metolachlor at 2.8 kg ha'1 were applied PRE
immediately after planting. Dimethenamid and metolachlor injured both cultivars on the
June 1 and June 22 planting dates in 1998. Dry bean response to either herbicide was
minimal to all planting dates in 1999. Environmental conditions at the time of emergence
affected dry bean tolerance to these herbicides. On the June 1 and June 22 planting dates in
1998 0.69 cm and 0.58 cm of rain, respectively, fell during the time of emergence (5 to 7
DAP). At the other planting dates in 1998 and at all planting dates in 1999, rainfall at the
time of emergence was 0 to 0.18 cm. Moderate temperature (22 to 31 C) did not appear to

play a signiﬁcant role in dry bean injury from dimethenamid or metolachlor.

71

INTRODUCTION

The chloroacetamide herbicides are commonly used to control annual grasses,
small-seeded broadleaf weeds, and yellow nutsedge (Cyperus esculentus L.) in corn (Zea
mays), soybeans (Glycine max) and dry edible beans (Phaseolus vulgaris) (Anonymous,
1992). Cultivars of these crops have exhibited variable tolerance to chloroacetarnides
(Renner et al., 1988; Driver et al., 1992; Edwards et al., 1976; Sniper et al., 1987; Stephenson
et al., 1976). Temperature, rainfall, placement of the herbicide, soil texture and organic
matter were important factors inﬂuencing tolerance in the ﬁeld (Cieslar and Binning, 1974;
Putnam and Rice, Jr. 1979).

Alachlor injured snap beans at both low and high temperature regimes with day and
night temperatures of 16 and 21 C or 27 and 32 C, respectively (Putnam and Rice, 1979).
At 16 to 21 C the injury appeared much earlier and was more severe compared with injury
at the high temperature. Plants at the low temperature displayed leaf crinkling or fusion of
the leaf margins, while plants at the high temperature exhibited leaf cupping and marginal
chlorosis (Putnam and Rice, 1979). Penner and Graves (1972) found that alachlor applied
at 3.32 kg/ha (twice the normal rate) caused injury to navy beans at 20 and 25 C but not at
30 C. Navy bean injury from alachlor at the lower temperatures may explain the occasional
injury observed in the ﬁeld (Penner and Graves, 1972).

Putnam and Rice (1979) reported that twice as much alachlor was taken up by snap
bean at the 27 to 32 C compared to the 16 to 21 C temperature regime. However, increased
growth rates and transpiration rates occur at higher temperatures. At the higher temperature
regime the majority of the alachlor remained in the plant roots. The percentage remaining

72

as parent alachlor was greater at the lower temperature. Alachlor was distributed throughout
the plant with no single part of the plant accumulating a signiﬁcantly greater amount of
alachlor than any other plant part except for the cotyledons in which no alachlor was found.
Therefore lower temperatures could result in more crop injury.

Many herbicides become more available for uptake by the plant as soil moisture
increases (Jones et al., 1990; Tripp and Baldwin, 1988; Wehtje et al., 1987). Metolachlor
uptake increased in grass species up to three-fold when soil moisture increased from 45 to
100% (Gerber et al., 1974.). In a ﬁeld experiment evaluating different soybean cultivars
neither dimethenamid or metolachlor reduced soybean yield when applied at normal use rates
with either optimum or excessive moisture. However, injury occurred when dimethenamid
or metolachlor were applied above recommended rates and excessive moisture conditions
persisted. Some soybean cultivars were more sensitive to dimethenamid compared to
metolachlor, but to reveal these differences a 3X herbicide rate combined with excessive
moisture were required (Osborne et al., 1992b). Other soybean studies indicate that the
magnitude of soybean injury is greater with dimethenamid compared with metolachlor
(Osborne et al., 1992a).

In 1996 dry bean planting was delayed until late June in Michigan because of
excessive rainfall in late May and early June. Dimethenamid injured dry bean in some ﬁelds
in Michigan. Environmental conditions at the time of planting and bean emergence may
have inﬂuenced dry bean response to dimethenamid. The objective of this research was to
determine whether environmental conditions at the time of planting and emergence
inﬂuenced dry bean tolerance to dimethenamid or metolachlor.

73

MATERIALS AND METHODS

Field experiments were conducted in 1998 and 1999 at the Saginaw Valley Dry Bean
and Sugar Beet Research Farm, Saginaw, Michigan. In 1998 the study was conducted on a
Misteguay silty clay loam (Aerie Haplaquept, ﬁne, mixed (calcareous), mesic), 9% sand,
45% silt, and 46% clay with a pH of 8.0 and 1.9 % organic matter. When the experiment
was repeated in 1999 the soil type was a Mistguay silty clay loam (14% sand, 47% silt, and
39% clay) with a pH of 7.8 and 2.6% organic matter. To eliminate the confounding factor
of weed interference on navy bean maturity and yield, plots were maintained weed-free by
hand-hoeing for the duration of the growing season.

The seedbed was prepared with moldboard plowing in the fall followed by two passes
with a Danish S-tine ﬁeld cultivator in the spring. ‘Vista’ and ‘Schooner’ navy beans were
planted in strip plots on ﬁve planting dates in 1998 and 1999 (Table 1). The ﬁrst planting
date each year was during the third week of May. Dry beans were planted approximately
every 10 days ﬁ'om the ﬁrst date of planting through early July. The plots, 4 rows wide and
6.7 m in length, were seeded at a population of 272,000 seeds ha" with a crop row spacing
of 71 cm.

Herbicide treatments applied to each navy bean cultivar included dimethenamid at
2.3 kg ha’1 PRE and metolachlor at 2.8 kg ha‘1 PRE. Navy bean injury was evaluated by
visually assessing the percent leaf area reduction at the unifoliate, 1“ trifoliate and 3rd
trifoliate stages. In addition three plants were randomly chosen from the middle two rows
of each plot at each evaluation date, cut off at the soil surface, and leaf area (cmz) measured
with a LI-3000 portable area meter (LI-COR, Lincoln, Nebraska).

74

Dry beans reach full maturity upon completing Stage R9. This development stage
is characterized by leaf senescence, leaf desiccation and leaf abscission. Physiological
maturity was determined by visually recording percent leaf yellowing on a scale from 0
(plants still in Stage R8, pod ﬁlling) to 100% (plants are fully mature and ready for harvest).
The maturity of each cultivar was compared to dry bean maturity in the untreated control
plots. Ratings were taken when leaves in the untreated control plots were two-thirds yellow.
Beans ﬁ'om 4.3 m of the center two rows were hand-harvested by pulling and threshed with
a stationary thresher. Yields were adjusted to kg ha" at 18% moisture.

The experiment was conducted twice as a randomized complete block design in a
multi-location split-plot arrangement. The ‘Vista’ and ‘Schooner’ navy beans were planted
in three 4 rows strips on each planting date. Treatments were randomized in the same
arrangement on each planting date within the strips. The ﬁve planting date were each
planted in different locations within the same ﬁeld. Dry bean cultivar was the main-plot
factor and herbicide treatment was the sub-plot factor. Data were subjected to analysis of
variance and means separated using Fisher's protected LSD test at P 5 0.05 level of
probability. Visual estimates of leaf area reduction were subjected to square root
transformation prior to statistical analysis. Nontransformed data are presented for clarity.
Data from 1998 and 1999 are presented separately because of year by date of planting by

treatment interactions.

75

RESULTS AND DISCUSSION

In 1998 dry bean injury from dimethenamid and metolachlor was greatest for the
June 1 and June 22 planting dates (Tables 1 and 2). Dimethenamid was more injurious to
‘Vista’ navy bean compared to metolachlor for all planting dates except May 21 in 1998
(Table 1). Dimethenamid also was more injurious to the ‘Schooner’ navy bean compared
to metolachlor for the June 1, 1998 planting date only (Table 1). Both herbicides reduced
the leaf area of ‘Vista’ navy bean planted on June 1 and June 22 and ‘Schooner’ navy bean
planted on June 22, 1998. Additionally, dimethenamid reduced the leaf area of the ‘Vista’
cultivar compared to the untreated control on the July 2, 1998 planting date. Because the
injury from dimethenamid or metolachlor varied greatly from one plant to another, the visual
injury ratings were more representative of the amount of injury caused by these herbicides.
In 1998 the leaf area of the plants treated with metolachlor was greater than the plants in the
untreated control plots on May 21, June 11, and July 2 (Table 2).

In 1999 dimethenamid was signiﬁcantly more injurious to dry beans than metolachlor
on May 20 and June 10 (Table 1). Dimethenamid reduce the leaf area of the ‘Vista’ and
‘Schooner’ cultivars for the May 20, 1999 planting date when compared to the untreated
control (Table 2).

Early season injury to dry beans from dimethenamid delayed maturity of ‘Vista’ and
‘Schooner’ navy beans for every planting date in 1998 except May 21. Metolachlor delayed
maturity of ‘Vista’ navy bean for the June 1, June 11, and June 22 planting dates, and for the
‘Schooner’ cultivar on the June 1 and June 22 planting dates in 1998. Dimethenamid
delayed the maturity of the ‘Vista’ cultivar at the May 20 and June 21 planting dates in 1999

76

(Table 3), while metolachlor delayed for the June 21 planting date in 1999. Maturity and
yields were not recorded for the July 6 planting in 1999 due to a frost prior to seed maturity.
Seed yields for each planting date in 1998 and 1999 were not reduced where dimethenamid
or metolachlor were applied compared with the untreated control (Table 4).

Dry beans planted on June 1 and June 22, 1998 incurred the greatest injury from
dimethenamid and metolachlor PRE at twice the recommended rates (Table 1 and Table 2).
Penner and Graves (1972) found that alachlor at 3.32 kg/ha (twice the normal rate) caused
injury to navy beans at 20 and 25 C but not at 30 C. The lowest mean temperature 0 to 10
days after planting (DAP) occurred after the June 1, 1998 and May 20, 1999 planting dates
(Table 5). Therefore cool temperature may have contributed to the injury seen for the June
1, 1998 planting date.

Many herbicides become more available for plant uptake as soil moisture increases
(Jones et al., 1990; Tripp and Baldwin, 1988; Wehtje et al., 1987). The amount of rainfall
received during the 10 DAP varied over the dates of planting in 1998 and 1999. The amount
of rain which fell in the 10 DAP on the June 1 planting date in 1998, 0.69 cm, was the lowest
recorded for the ﬁve planting dates in that year (Table 5). The dry beans planted on June 22
received 1.07 cm over this period of 10 DAP (Table 5). The amount of rain that fell during
the 10 DAP on the ﬁve dates of planting in 1999 ranged from 0.66 to 3.15 cm. There was
minimal injury ﬁ'om dimethenamid and metolachlor to navy beans for all of these planting
dates (Table 5).

The amount of rain which fell during the 3-day period of bean emergence (5 to 7
DAP) was greatest for the June 1, 1998 and June 22, 1998 planting dates (Table 5). The

77

rainfall received at the time of emergence (crook stage) for the other three planting dates in
1998 and all planting dates in 1999 was 0.18 cm or less (Table 5). Dimethenamid and
metolachlor became readily available for uptake at this time when the bean hypocotyl was
growing through the PRE herbicide treatment and emerging from the soil surface. In
greenhouse research dry bean injury was greatest when the hypocotyl was exposed to
dimethenamid (Poling and Renner, 1998). In other ﬁeld research, dimethenamid applied
PRE to navy beans in 1999 resulted in 40% injury 10 DAP compared with the untreated
control (Renner and Kells, 1999). In this research 1.2 cm of rain fell during the time of
emergence (5 to 7 DAP). Our results do not agree with that of Osborne et al. (1992b) where
injury to soybeans occurred when dimethenamid or metolachlor were applied above
recommended rates and excessive moisture conditions persisted. In our research moisture
at the time of dry bean emergence appeared to be a critical factor in dry bean injury from

dimethenamid or metolachlor PRE.

SUMMARY
Environmental conditions that occur following application of dimethenamid or
metolachlor affect dry bean tolerance to these herbicides. The quantity of precipitation that
a dry bean ﬁeld receives at the crook stage following an application of dimethenamid or
metolachlor is crucial. Rice and Putnam (1980) observed that early uptake of alachlor in
snap bean occurred primarily via the shoot portion of the emerging seedling. Rain at the

time of emergence could increase the amount of herbicide absorbed by the dry bean

78

hypocotyl and result in crop injury. Moderate temperature (22 to 31 C) did not appear to

play a signiﬁcant role in dry bean injury from dimethenamid or metolachlor in our research.

79

LITERATURE CITED

Anonymous. 1992. SAN 582G experimental herbicide: A technical overview. Sandoz Agro,
Inc., Des Plaines, IL 60018.

Cieslar, B. and L.K. Binning. 1974. Translocation of 14C-alachlor in lima beans as related
to phytotoxicity. Proc. North Cent. Weed Control Conf. 29:323.

Driver, J .E., T.F. Peeper, and A.C. Guenzi. 1992. In vitro selection for increased wheat
tolerance to metsulfuron. Proc. South. Weed Sci. Soc. 45:316.

Edwards, C.J., Jr., W.L. Barrentine, and TC. Kilen. 1976. Inheritance of sensitivity of
soybean cultivars to metribuzin. Crop Sci. 16:119-120.

Gerber, H.R., G. Muller and L. Ebner. 1974. CGA 24705, a new grass killer herbicide. Proc.
12th Br. Weed Control Conf. 32787-794.

Jones, R.E., Jr., P.A. Banks, and DE. Radcliffe. 1990. Alachlor and metribuzin movement
and dissipation in a soil proﬁle as inﬂuenced by soil surface condition. Weed Sci.
38:589-597.

Osborne, B.T., D.R. Shaw, and R.L. Ratliff. 1992a. Soybean cultivar tolerance to SAN 5 82H
and metolachlor as inﬂuenced by soil moisture. Weed Sci. 43:288-292.

Osborne, B.T., D.R. Shaw, R.L. Ratliff, and G.P. Ferguson. 1992b. Soybean cultivar

tolerance to SAN 582 and metolachlor as inﬂuenced by soil moisture. Proc. South. Weed Sci.
Soc. 45:52.

Poling, K.W. and K.A. Renner. 1998. Dry edible bean response to dimethenamid and
metolachlor. Proc. North Central Weed Sci. Soc. Vol. 43: 120.

Penner D. and D. Graves. 1972. Temperature inﬂuence on herbicide injury to navy beans.
Agron. J. 64:30.

Putnam, AR. and RP. Rice, Jr. 1979. Environmental and edaphic inﬂuences on the
selectivity of alachlor on snap beans (Phaseolus vulgaris). Weed Sci. 27:570—574.

Renner, K.A., W.F. Meggitt, and D. Penner. 1988. Response of corn (Zea mays) cultivars to
imazaquin. Weed Sci. 36:625—628.

Renner, K.A. and J. Kells. 2000. 2000 Weed Control Results in Field Crops. Department of
Crop and Soil Sciences. Michigan State University.

80

Rice, RR, Jr. and AR. Putnam. 1980. Temperature inﬂuences on uptake, translocation, and
metabolism of alachlor in snap beans (Phaseolus vulgaris). Weed Sci. 28(2): 131-134.

Sniper, C.E., J .E. Street, and D.L. Boykin. 1987. Inﬂuence of ﬂood interval and cultivar on
rice (Oryza sativa) tolerance to fenoxaprop. Weed Sci. 35:842-845.

Stephenson, G.R., J .E. McLeod, and SC. Phatak. 1976. Differential tolerance of tomato
cultivars to metribuzin. Weed Sci. 24:161-165.

Tripp, TN. and FL. Baldwin. 1988. Effect of excessive precipitation on soybean injury from
imazaquin and chlorimuron. Weed Sci. Soc. Am. Abstr. 28:39.

Wehtje, G., R. Dickens, J.W. Welcut, and BF. Hajek. 1987. Sorption and mobility of
sulfometuron and imazapyr in ﬁve Alabama soils. Weed Sci. 35:858-864.

81

 

 

 

 

 

 

 

 

 

 

 

: 0: :00 >0
we we we we we we mo wo wo wo 02005::
0 : 0-0 0 0 _ 0-0 0 0 _ 0 0 00 2 0 o 00 M: 0 m 020000008
0 : 0-0 0 00 0 00 0 0-0 0 00 0 00 mm 0 _ 0 mm 0 0 20000050000
. 00:00:05
wo wo wo wo we we we we we we 03005::
00 0 0-0 .0 0 m 00 0 0 _ 0 m 0 0: 0 o 0 a 0 0 020003008
:0 m 0-0 m :0 v :0 Z 0-0 m 0 n 0 0m 0 v 0 mm 0 0 05055085
07.5
0x. 0\0
0 :0: 5 0:3. :— 0:3. _ 0:3. om :02 N 33. mm 0:3. 2 0:3. _ 0:3. :N :02 0:09:02:-
mmm: woo:

 

0w000 538w 20:55 .0: .0 b: .8: :03;

 

.32 0:0 mom: 5 00000 w:::0_: 0>: :o 0350 53on 80:55

.0: 05 00 mm: 00: we: w.N 02500—808 0:0 .0: m: m.m :0 38055055 :8: :00: 0:00: .0550? 0:0 52>. :o 50.8: ._ 030.:-

82

 

 

 

 

 

 

 

IBI Ioml Iﬂl Isl I07 IEI I00.- ISI Ivml |0| @050
-02- IE- Iawl 1001 Imml ISI .00:- Imml Ivml 1:0-I Godweam:
gm ovm 00m mom :m: Gm mmm n : N mm: mm: 08005::
mom mm: Em :0: m0: cum 0N: Nvm mm m: 8200:0008
mmm on: mwm :0: 0:: 03 cm gm ow 00: 28805085
00:00:0m
co: mum 00m mom m0: com cum :mm mm: m: : 08005::
0mm mm: com mm: 0:: 00m om: vmm :w mm: 8200:0008
:3 mm: mmm mm: mm am: an: w:~ 0m 0:: 28055085
065
N80 N80
0 33. :N 0:3 0: 0:3 : 0:3 om >03: m :3. mm 0:3. :: 0:3 : 0:3 :N :3): 808008.:-
000: mom:

 

0:000 538w 80:55 .0: :0 00:0 :00:

 

.30: 0:0 mam: :: 00:00 w:::0:: 8000-50 0>: :o 0w0:m 538w 80:55 .0: 05

:0 00:0 :00: :00: E0 090: .0850? 0:0 .085. :0 man: 70: w: w.~ 8200:0008 0:0 _-0: m: m.m :0 05055085 :0 80.5: .N 030-:-

83

30:0» 0088 :0: 32: 38:00 08008:: 05 8 0262 05 00 X8 380880880 :055 0000203 £020; 003 bt808 a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

a h g >0
2 0 Erma :3
I S Sn 3 S S S S S S 03805
I S S S S S S S S S 8222908
I S S E S S S S S S 2.585080
:0:oonom
I S S S S S S S S S 0280::
I 8 S S S S S S S S 52832:
I S Q ow S S S S S S 28085056
90>
,x. .x.
o 33. a 0:3. 2 0:3. M 0:3. om >02 N 33. mm 08:. Z 08:. _ 0:3. _m >02 808:00CI
mam_ 000:
$8302

 

.32 0:0 Se 5 800 0:803 «>0 820
3:808 :00n >>0: .8823? 0:0 .055. :0 min 70: 3 w.~ :0 8200—908 80 70: wx Wm 00 28055083 .8 80.0.5 .m 030.0

84

08668 $32 8 0000300 0

 

 

 

 

 

 

 

 

85

 

 

 

 

 

 

 

0 5 £0 >0
m: a Sodwg :3
I SS 3% S: SS SS 88 8: ES SM: 0280::
I SS S8 ES SS SS S: SS 88 S2 8302905
I 2S SS SS SS SS S: SE SE :2 28085086
Honoosom
I 8S. S; SS SS S: S8 2:: NS: SS: 0380::
I SS OS? SS. NSV S: SM: a: 88 S: 323.905
I SS S8 SS S3 5: a: 9% SM: 2: 25055080
30>
:2 00. _2 00
0 >33 2N 0:3 2 0:3 2 0:3 om >02 N >_3 mm 0:3 2 0:3 _ 0:3 5 >02 808000;
000_ SSS:
.20;

 

6mg 6:0 wag :m 00:0:
wEEﬂa 0>a 80¢ 22> :00: >8 :0 mdm 70: wx w.N 00 83003008 0:0 70: wx md 00 28805086 mo 80:00:33 mo 80am .0 0E0H

 

:2: 2-8

 

S0 2.». SS 000 SS S: S: 3: $0 S: .8? 850: 0233882
02:03::
80 SS 80 20 80 8.0 8.0 8.0 8.0 S0 .5? 3%:
:2: we
8.0 2.0 20 80 0:: 2.0 S0 20 Sd mod .5? 00:50:
8.4.: v-8
0:: 8.0 SS S0 S: S: 93 30 8.0 Ed .5? :05“:
02:20:
S S S S S S S S S S -0- 2323509 :82
:2: 2.8
S S S S S S S S S S -0- eaeaeﬁ :82
:2: E:
S S a: S E S S S S S -0- eaeaeﬁ :002
:2: #8
S S S S S S S S 2 a: -0- 03:800an :002
S

>_3 80:3 o— 0:33 : 0:3 om >02 N>_3 mm 0:3 2 0:3 : 0:3 :N>02 :0:080:0m _0::08:o:_>:m

 

:3: mg:

 

.03: 0:0 waa: 8
w:_::0_: .:o 0:00 :000 :0 0w0:m 0:080 0:: :0 =00:_0: 0380383000 0:0 E<Q o: £0308: =0::_0: .Ead o: 08:80:80: :002 .m 030%

86

APPENDIX

 

 

 

 

S: S :00 >0

 

 

 

 

 

 

 

 

 

 

 

S: S: :SSSWS: :S:

S S S S SS 3 S S S S 0280::

S S S S SS S S: S: S S: S 8:08:20:

S SS S S S S S: S S S: 00 05055088

S S S S :S S S S S S S: 08055085
N80 N80 :0: w:

SSS 0:00:02 0852 :SSSESS 00> SSS 50:00:): 08302 082% 00> 23: 0:00.00:

SSS: SSS:

 

dam: :80 mom: :: 00.80 530% 0:23:80 0:: :0 00:0 :00: :00: 0:00:: 0mm? :80 .::w::22. 0:0
:00: >20 >>0: .t0:>>0Z. 0:0 35:00:09 ..0:S:>. :0 mm: 82:03:08 :80 28805086 :0 82:02:50 :0 :00::m: .: 2:05 80:08?

87

 

 

 

 

 

S S :00 >0

 

 

 

 

 

 

 

 

 

 

 

:S S: :Sodwa :S:
SS 3: SS SS :0 SS SS SS SS SS 0080::
SS SS :S SS0 :0 «S SS SS SS SS S 8:08:00:
SSS SS :0 :S S SS SS SS SSS SS 00 0005008:
SS SSS SS SS SSS SS SS 3S SS 80 S: 08080005
N80 N80 :0: m:
S»: 0:00:02 8:52 082% 00> SS: 0:00:02 8:57: 88:00, 00> 03: 00005::
SSS: SSS:

 

.000: :80 w00: 8 0w0:S ::>>0:w 0:0:0:::: 0m 0:: :0 00:0 :00: :00: 0:00:: .00.»? :80 .::w::22. :80
:00: >8 >>0: 20:302. :80 ..:0:00:0m. 0:2? :0 man: 8200388 :80 28805086 :0 82:00:80 :0 :00::m: :0. 030,0 8:80:50:

88

 

 

 

 

 

 

 

 

.ISI IS:I IT. IS:I. ISI ISI IS:I IS:I IS:I ISSI 0S:>0
lm:l leml |0| lm:| |0N| lmvl Ioml INNI ISII lmvl Amodwgﬂm:
00 m: : :w 0m :m: 0N: N0 0: w: en 00:00:::0
mm mm 0: mm 0:: mm :m :0 mm m: 8200208
:0 mm 0m 0m 00: mm :0 mm N: mm 280:0::08:0

:0:00:0m
E 9:: on 0m 0: 00 w0 o: w: :m 00:00:80
w: n: 0: mm m: :0 mm 0w 0: 0:: 8202808
0: n: 0: :m :0 :0 m0 0: : : :m 280:0::08:0
0:S:>
:80 N80
0 >03 :N 0:3 0: 0:3 : 0:3 ON >02 N >03 mm 0:3 :: 0:3 : 0:3 :N >02 ::08:00:I:I
000: :00:

 

0w0:S 530:» 20:88: :0 00:0 :00:

 

.000: 0:0 000: :: 000:0 ::30:0 80:28: 0:: :0 00:0 :00: :00: >.:0 >>0:
.5880? 0:0 .02? :0 man: _.0: w: m.m :0 8202808 0:0 _.0: w: SN :0 28805080 :0 80:00:80 :0 :00:: .m 030:: 80:08:40:

89

 

 

 

 

 

 

 

 

I::I ISI IS:I IS:I ISI IS:I ISI ISI |S| IS:I 0S:>0
INm: I INwNI IN0: I I:0NI IommI I0O:I IwNNI IN0: I lowl low:l Amodec QmI:
w:w mm: 0mm won New 000 000 N0: 0.0.0 000 00:00:80
30 0mm 30 0mm wNm w0m S00 w0> N0m mmm 8202208
$0 00m :00 Nmm m :0 mmm N00 mm0 SNm :00 28805088

:0:00:0m
0w» 2% w0m N00 m: :N0 00:. :0: ::m mom 00:00:80
SS 00m w :0 0m: 0:: 000 :00 :0: now 0: m 8202208
00m Gm 000 :2. mmm mmm 0N0 80 0mm :mm 28805080
02>
:80 N80
0 >:3 :N 0:3 0: 0:3 : 0:3 oN >02 N >:3 NN 0:3 :: 0:3 : 0:3 :N >02 ::08:00:.:I
000: w00:

 

0w0:S ::30:w 0:0:0:::: 0m :0 00:0 :00:

 

.SSS: :0:0 SSS: 0 000.: 0320 00:00 2S 2:: 0 0:0 :0: :02: 0:. 30:
.:0:00:0m. 0:0 .02? :0 man: :.0: w: wN :0 8202208 0:0 :.0: w: m.N :0 28805088 :0 82:00:80 :0 :00::m: .0 050:. 80:89::

90

"’VIIIIIIIIIIIIIIIIIIIIIIII“