l H IHI Egg}; WIHIHIIHIIIHWIHHIIlillll'lllll I 2 ." .“ 9- ‘1 I \n H .4. v§ ‘. LA ' K; [\b . . '1}: 1" ' \ - a 1 w b! .1 D a It ‘ X: . ‘-\" .1t 1". I9, . '1\ xi. '-. "4 '\ x 4 ~‘-' Viia‘l 'a. \t’ 1 w a.’ \ ‘0 6 .‘ .c‘ .‘ \D A -5.’ I ) wfifi‘s _-_. _.__ ‘ ' _ \ .— __ ___ - . - _.-_... k‘ fi.‘ ' __i . AMA—‘9. . , This is to certify that the thesis entitled Chemical Control of Dow Bromsgrass (Brows Toctorum) In An Established Alfalfa Field. presented by Mark G. "111’.” has been accepted towards fulfillment of the requirements for “.8. Farm Crops degree in Ma)or professor Date?.f/uff //U.J- 0-169 CHEMICAL CONTROL OF DOJNY BnOML-GRASS (Bromus tectorum L.) IN AN ESTABLISHED ALFALFA FIELD Bf Mark G.Ydiltse . ‘—_—-I' A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Farm Creps 1952 /;-;.¢-~gz. ‘R\ AC Kit“ m" LED SPENT Acknowledgment is due to Professor Boyd R. Churchill for his kind assistance, advice, and encouragement in.making this thesis possible. ‘ \IVV‘I \-‘\I\ \I whnfi.mmfiv* .v_v v_.\'_.\4..v \ ‘3'; n K‘A n n a aaaara §%*% * '3': It ‘29 {2:3 {I l“ {a "" 'Nt I“): _)‘ I TABLE OF COB: ‘liI‘J'l‘S PAGE INTECDUCTION . . . . . ..... . ......................... . .................. l REVIEN OF LITA-LT U 111:} ........................................... . . . . 2 I‘ZATLQELRLS AND MATHODS ..................... . ........................ 6 Ri-J'SULTS AND DISCUSJCN ........................ . .................... 10 Time of Application Experiment .............................. . . 10 Effect of Temperature on Seed Germination ............... . ..... 15 Effect of Dormancy on Germination ......... . ................... 16 Control of Downy Brome-Grass in the Field .................. . .. l9 TERRY .......................................... . ................ . 30 BIBLIC GrtAPHY ............................ . ...................... . . . . 32 INTRODUCTION INTRODUCTION Downy brome-grass (Bromus tectorium L.) is a problem in pastures, hayfields and waste places on the light sandy soils of southern Michigan. It generally behaves as a winter annual but it occasionally behaves as an annual. Downy brome-grass can be controlled easily in a cultivated field since it reproduces only by seeds. Cultivating the fields in the fall or spring after the seeds have germinated will give adequate control. Since hayfields and pastures are not clean cultivated, downy brome-grass often becomes a serious problem. 'ihen pasturing or feeding hay infested with downy brome-grass, the awns of the seed may cause irritation of the mouths of the animals. The awns may also affect animals by lodging in their nostrils, eyes, and intestines. Downy brome-grass is very drought resistant and.competes with alfalfa for the use of water when the available water supply is low. Because of these various reasons it is desirable to eliminate downy brome-grass in hay and pasture crops. Attempts have been made by farmers to reduce downy brome-grass by cutting the hay crop early or by pasturing early. If the seeding is worked up and the field reseeded, it entails considerable expense to the farmer in labor, machine expense, and grass seed. If an economical method of controlling downy brome-grass can be per- fected, it will be a help to the grass land farming areas of southern Michigan and elsewhere. The chemical control of downy brome-grass shows promise at this time. RhiVIrl-J OF LITLL'ILATUELE REV—Ir}. OF LITrilLATU TIE: Megee (h)% found that downy brome-grass behaved mostly like a winter annual but that some seedlings are annuals. In germinating seeds at dif- ferent times of the year, he found the seeds did not germinate during mid-summer but germinated in September when the fall rains fell. He attributed the fact that there was no germination in mid-summer to the dryness at this time of the year and that there was a rest period which the seed must go through before germination would take place. Megee also found that if the seeds were allowed to mature past May 15th they would germinate and cause a serious infestation. The seeds germinated less than 50% when they were harvested in the dough stage. The seedlings that became well established in the fall produced an abundance of seed the following spring. The downy brome-grass seedlings that were not well established by the latter part of October produced very little seed the next season. There has been little work reported on the use of chemicals for controlling downy brome-grass. Darlington, Bessey, Hegee and Grigsby (1) recommended the use of stoddard solvent for the control of small patches of this weed and they further state that it should be applied before the plant heads out. * Number in parenthesis refers to bibliography, page 32 . The chemicals used most in the research reports of the North Central Weed Control Conference for the control of weedy bromes have been iso- propyl-V phenyl-carbamate (113(3)?‘ and trichloro acetic acid (TCA)*, Grigsby, Churchill, Hamner, and Carlson (3) state that IPC will kill annual grasses, cultivated grains and, under some conditions, perennial grasses. They state that IPC will also kill or injure some broad-leaved plants. IPC exerts a toxic action on the roots of grasses. It has a residual action, but decomposition is rapid and no further effects are found in most soils after a period of two to four weeks. An application of 2 to 5 pounds of IPC per acre may give control of annual grasses. Darlington, 33 El. (1) state that the sodium salt of TCA has given good control of Quack grass and most annual grasses. It is toxic to all parts of all plants, but it is most effective when applied as a soil treatment. Treatments may be made at any season of the year but are most effective in the fall and early spring. Soil which has been treated with TCA will not be suitable for crop plant growth for 30 to 90 days follow- ing treatment. They further state that S to 10 pounds per acre applica- tions may be sufficient for the control of annual grasses if applied when the grass seeds are germinating. TCA may cause injury to the legume crops when applied to the soil in which these plants are growing according to preliminary results ob- tained by Grigsby, 23 El. (3). * These chemicals will be referred to as IPC and TCA. Finnerty, Klingman, and Shafer used both TCA and IPC in an attempt to control weedy bromes in a Nebraska experiment. Applications were made in the late fall and in the early spring. IPC at 10 pounds gave 60% control in the spring treatments and 70% control in the fall, while the 20 pound rate gave 87% and 90% control, respectively. Sodium TCA at 10 pounds and 15 pounds per acre gave over 90% control. They stated that all rates of IPC or TCA which gave 80% or better control of the weedy bromes reduced the smooth brome grass stands from 16% to 93%. Neither of these materials gave satisfactory selective control in perennial grass stands; however, IPC and TCA did give satisfactory control of the weedy bromes. ‘Natson (9) Sprayed an established field of alfalfa that was infested with downy brome-grass and quackgrass with sodium TCA. The spray was applied at the rate of 100 gallons per acre in November when the downy brome-grass was two to three inches high. All rates of ten pounds per acre and higher eliminated the downy brome-grass. Slight alfalfa injury was noticed on the alfalfa the following Spring with the seventy—five pound rates and higher. This injury was not apparent by cutting time. Shafer (7) Sprayed alfalfa for the control of annual weeds in Nebraska. He found that IPC at 2 and 8 pounds per acre effectively con- trolled little barley, green and yellow foxtail, and barnyard grass but with injury to the alfalfa. Miller and Dunham (5) did some additional work on the effect of IPC and TCA on legumes. Applications of 10.6 and 5.3 pounds acid equivalent TCA and 8 and h pounds IPC were applied in the spring when the alfalfa was four inches high and on other plots immediately after the first hay crop. Alfalfa was not damaged by the TCA and showed only slight burn- ing with the IPC at the first date of application. TCA reduced the stands of foxtail while IPC gave no weed control. No damage was noticed in the alfalfa at the second date of application. Peters andifillani (6) applied TCA at rates of 0, 10, 20, hO, and 80 pounds per acre on alfalfa, The applications were made on July 18, October 12, November 15, 1950 and on.Apri1 S, 1951. In the July appli- cation, 20 pounds and above gave very little damage to the alfalfa but in the following Spring the alfalfa density was reduced to 10k and 50% of the check at the BC pound and 20 pound rate, reSpectively. In the October application, some temporary effects were noted in the spring of 1951 but by June 7, 1951 no evidence of treatment could be noticed in the alfalfa. The November application had no effect on the alfalfa. The April treat- ments reduced the density and height of the alfalfa slightly at the 10 and 20 pound rates. At the hO and 80 pound rates, the height of growth decreased one-half and two-thirds reSpectively; although, there was little change in density.. Leathpper damage was greater at the higher rates of application. Shafer and Finnerty (8) used IPC as a soil treatment at 3, 6, and 9 pounds per acre on 100 germinating seeds of four different grasses, namely: crabgrass, downy brome-grass, yellow foxtail, and hairy chess. Seedling counts were made at two weeks. IPC at 6 and 9 pounds per acre gave kills approaching 10‘% on all four grasses. I'L‘.T2.hIALS AND MSTHODS MATEAIALS AND l'h‘sTHC'DS An experiment was conducted to determine the best stage to apply herbicides to downy brome-grass to get the best kill. Fifty downy brome-grass seeds were seeded on one square yard plots on April 22, 1952 at East Lansing, Michigan. The soil was a clay loam. The seeds had been harvested on November 1, 1951. TCA* was sprayed on the plots with a hand Sprayer at S and 10 pound rates at seeding time, emergence (May 6th), two weeks after emergence (May 20th), and four weeks after emergence (June 3rd). The applications were run in triplicate and randomized. Seedling counts were made on June 23rd. The seedlings were cut off at the ground level on the same date and placed in a drier. From this data the number of plants, total dry weight, and weight per plant were determined. The stage at which the downy brome-grass plants were the most susceptible was determined by this time of application experiment. To determine when the plants would reach this stage under natural condi- tions additional experiments were made. A germination experiment was conducted in December of 1951 at the Farm Crops Greenhouse at Michigan State College. This experiment was designed to determine if the downy brome-grass seeds would germinate in warm weather of summer as well as cool weather of fall. Both old and * The TCA used in all of these experiments was the sodium salt of trichloro acetic acid with 9C% acid equivalent. new seeds were used in the experiment to get an idea of how dormancy might influence the germination at the various temperatures. The old seed was one year old and had been obtained from screenings. The new seed was harvested on November 1, 1951 from plants growing on the college farm. Four different temperatures were used approximating no, 55, 68, and 85 degrees Fahrenheit. The hO degree test was placed in a refrigerator set at this temperature. Different rooms were used in the green house for the 55, 68 degree tests. A germinator was used for the 85 degree test. All of the tests were made in plastic boxes that were b 1/2 by b 1/2 inches. Fifty seeds were seeded in quartz sand to a depth of 1/h inch in each box. Seedling counts were made at the end of two Weeks. The length of the dormancy period of seeds harvested at different stages of maturity was the basis for another germination experiment. Downy brome—grass seeds were harvested in the milk stage (June 9, 1951) in the soft dough stage (June 16th), and in the hard dough stage (June 23rd). Nine days after the last harvest date germination tests were made on the different lots of seeds. To determine what effect dormancy had on the seeds, the dormancy was broken in part of the seeds by treat- ing them with a 0.2% KNOa solution and by subjecting them to a 5 degrees Centigrade temperature for five days. Both the treated and untreated seeds were tested in triplicate. One hundred seeds were planted in h 1/2 inch by b 1/2 inch plastic boxes at a depth of l/h inch in Quartz sand. The seeds were then germinated under outdoor temperature and light con- ditions as prevailed at Ellsworth, Michigan in July) 1952. Seedlings were counted ten days after seeding. Identical tests were made at ten day intervals to try and determine how long it would take to break the dormancy under natural conditions. The germination dates were July 2, July 12, and July 22, of 1952. The actual Spraying of an alfalfa field infested with downy brome- grass was conducted on a light, gravelly loam twelve miles west of Pontiac, Michigan. The alfalfa field was one year old and was heavily infested with downy brome-grass and scattered areas of Kentucky blue grass. Fifty-one plots, twenty-five feet by seventeen and one-half feet (0.01 acre), were laid out in the field. By observation, each plot was rated as to the content of downy brome-grass. The classifications used were heavy, medium, light and no downy brome-grass. The sodium salt of trichloroacetic acid (TCA)and iso-prOpyl-N phenyl carbamate (IPC) were the chemicals used as herbicides. The herbicides were used at l, 5, 10 and 20 pound per acre rates. Fall applications were applied on October 31, 1951 when the downy brome-grass seedlings were approximately two inches high. The spring applications were made on April 26, 1952 after spring growth had started. The plots were randomized in triplicate. A knapsack Sprayer with two fan type nozzles mounted eighteen inches apart was used for Spraying. Ninety gallons of water per acre was used for the TCA in the fall and spring and also for the 1 and 5 pound rates of IPC in the fall. The 10 and 20 pound rates of IPC in the fall was applied with 135 gallons of water per acre. All of the spring applica— tions of IPC were applied with 180 gallons of water per acre. At the time of harvest, June 7, 1952, the plots were rated by observation as to the amount of control of the downy brome-grass. The ratings used were excellent, medium or poor control. Observations were also made at this time to determine the extent of damage to the alfalfa and to note the deformation of the vegetation. Three foot alley ways were cut around all plots and a 0.001 acre portion harvested through the middle of each plot to determine yields. Samples were taken and botanical separations made to determine the percentage of downy brome-grass on a dry weight basis. Samples were also taken to determine the moisture percentage. lith this experiment the actual effects of the rates, time of application, and type of herbi- cide upon the downy brome-grass and alfalfa was determined. new LT S AN D DI SCU SSION RESULTS AND DISCUSSION 10 In all of the experiments conducted for this problem, the ultimate objectives have been to determine: (1) what herbicides to use to kill downy brome-grass in alfalfa, (2) how many pounds of the herbicide to apply per acre to obtain the best kill of the downy brome-grass with the least damage to the alfalfa, and (3) at what time of the year the appli- cation of the herbicide would control the downy brome-grass best and harm the alfalfa the least. Time of Application Experiment Table I shows the effect of applying TCA at 5 and 10 pound per acre rates to downy brome-grass at various stages of growth. TABLE I EFFECT OF THE TIME AND RATE OF APPLICATION OF TCA ON THE NUMBER OF DGAJNY BROME-GhASS PLANTS AND THEIR DRY WnIGhT Number Total Dry Dry weight Applications of TCA of 'Weight in Per Plant Rate Pounds Plants Grams In Grams Per Acre Time Check Check 1h.3 22.0 1.5h 5 Seeding 5.6 h.L 0.77 5 ,Emergence 9.3 10.0 1.08 5 '2 weeks after emergence 12.0 17.3 1.hh 5 h weeks after emergence 10.0 6.3 0.63 10 Seeding 1.7 0.01 0.01 10 Emergence h.3 1.0 0.23 10 2 weeks after emergence 1b.? 7.0 0.h8 10 h weeks after emergence b.7 2.8 0.60 11 The ten pound per acre rate reduced the number of plants per plot more than the five pound rate except at the'two weeks after emergence' stage. The number of downy brome-grass plants were the least in both the five pound and ten pound rates when the herbicide was applied at seeding time. There were more downy brome-grass plants when the herbicide was applied at the 'two weeks after emergence' stage than when applied at the 'four weeks after emergenoe' stage. This may have been due to the fact that rain fell for six consecutive days after applying the herbicide at the 'two weeks after emergence' stage, and the total amount of rain in this period was 3.3 inches. This excessive amount of rainfall may have rendered the TCA less active, or the 'two weeks after emergence' stage may be a period in the plant's growth when it is more resistant to the herbicide. The comparison of the number of plants per plot when Sprayed with TCA at both 5 and 10 pounds per acre rates at four different stages of growth is shown in Figure 1. The total dry weight of all the downy brome-grass plants was the least when the TCA was applied at seeding time for both the 5 and 10 pound per acre rates. The 10 pound per acre rate of TCA reduced the total dry weight more than the 5 pound rate. The 'two weeks after emergenoe' stage of spraying produced the most dry weight at both rates. A graphic comparison of the total dry weight yields is shown in Figure 2. A comparison of the dry weight per plant of downy brome-grass when Sprayed.with TCA at two rates and at four different stages is shown in Figure 3. .fl0(.: .U£3>JA.I 700 E.“ .11 1 01... Z‘U.1Ua( auiiu 2. I5: .1»... n; 1?: v.2 Inna...— 3:15. .21.” 331 . c4 c . 3. 1 o< . z<...:u£< an .:H o. :5: In .u. .. Max...» . 5% —..-:;~ .umd01 TOO Eda-(1 C C(& Z11 .50 I 11 4 I E CD I I 1 5 - _ I . I , 1 ' . 1 I I " “-0— o— I I . I .. r1. . 1_11 -1- -- _ --rw---_ ”.1 - -_11_ fi._,. 11 1 . i . . I , r , I 1 1 I. .I u - I I ' ‘ 1 a 1 "" U .30 . I l I I ' 1 L g '1 I ' I l u I '1 I ' I 1118.13 . -1-.- -- - i “.1- - -- -- "19--.--. WT. _- , I I I 1 ‘ 1 ’ I . I ; ‘ I‘ , I I 1 I0 ‘ I I I ‘ z I I' 1 f I 'I I 1 ‘ a I , . 1 nt U Hard doufh s 'I‘ I Leakinp.the Seeds.in .ZZIKNO ugity, when a I :I. I I I I I __. .. 1 .——--_.__. - Comparison of the extent of dormancy of downberome-grassIseeds, harvested at three stages of mat erminated at‘ten I I 4.4.“..- — _._ - - .._.-_.. >0-..-.—5 ___.--” - _-_ reatedi tage __§-]-1 395 days. Figure 6 Left: An excellent control plot receiving 5 pounds IPC per acre in the fall. Right: A poor control plot receiving 1 pound TCA per acre in the Spring. 21 Figure 7 Left: A plot sprayed with 20 pounds TCA per acre in the fall. Right: A plot sprayed with 20 pounds TCA per acre in the spring. 22 23 The plots that were sprayed with IPC at the 20 pound per acre rate showed some alfalfa injury in both the fall and Spring applications. The downy brome-grass that remained in the plots sprayed with IPC at 5 pounds per acre and more in the Spring was stunted. These downy brome- grass plants were only about four inches high but they were heading out. The Kentucky blue grass was stunted and was not heading out in the plots Sprayed with 10 and 20 pounds per acre of IPC in the fall. This effect is shown in Figure 8. Some injury to the alfalfa was observed when the TCA was applied at the 20 pound rate in both the spring and fall applications. A slight yellowing of the leaves of the alfalfa was very evident in the Spring applications. IPC gave excellent control in the fall and Spring applications with the 10 and 20 pound per acre rates. Figure 9 Shows a plot sprayed with 10 pounds of IPC per acre in the fall compared with a check plot. Table IV shows the average yields of the plots in the field trials. The total yields and the alfalfa yields are listed on the dry weight basis in pounds per acre. The downy brome-grass is listed as percent of the total yield. The check plots compared favorably with the sprayed plots in total yield per acre. The percentage of downy brome-grass was much greater in the checks than in the Sprayed plots. Figure 10 shows the effect of treatments upon the percent downy brome-grass. The best control was obtained with PC applied in the fall. .An insignificant amount of downy brome-grass remained in the plot sprayed Comparison of the effect of 10 pounds per acre of IPC Sprayed in the fall (left above) and 1 pound per acre of IPC sprayed in the spring (right above) when applied to alfalfa infested with Kentucky blue grass. 211 Figure 9 Comparison of a check plot (on the left) with a plot sprayed with 10 pounds of IPC in the fall (on the right). 25 TABLE IV EFFECT OF THE RATES AND TIME OF APPLICATION OF TCA AND IPC UPON THE YIELD OF AN ESTABLISHED ALFALFA FIELD INFESTEDIQITH DUANY BriOME -GRASS Herbicide Time of Rate of I Total Yield Percent Alfalfa Applica- 1 Applica- in Pounds Downy Yield tion tion in Per Acre Brome-Grass Pounds per Pounds Acre Per Acre Check Check Check 2917 hh.2 1635 TCA Fall 1 2762 16.6 2290 S 3153 2.1 309h 10 3271 3.0 3179 20 2682 1.0 2655 Spring 1 2711 21.8 2o9h 5 2h68 19.9 1983 10 2269 lh.0 2008 y 20 Zlhh 12.6 1877 IPC Fall 1 2718 7.9 2503 5 2983 0.07 2981 10 2313 0.03 2312 20 3051 0.2 30h6 Spring 1 2858 13.5 2L66 5 2180 10.6 1990 10 3153 1.2 3115 20 1923 2.3 1880 Ar‘i1!-;\-11 qo _ ___, _.-_. ._ __.__~_.- 1 v . | .--_. 1T .__-_.11-._.-__ . 201 [5 Per-cant ‘DownyeBromé Io i [ Figure 9 Compari k\\\\\\\\\\\\\\\\\\\\\\\\\\\\j IN Check brome- l # 27- son of the dfflects of TCA and IF; upon the rass when applied at different times and re Fall applications Spring applications [__ TCA applications _ IPC appncations L \ \ SI . Check .7: Z . r z — l l a l l [— S # 10 ,4 2o # 2. * .'I__ Rates of Applications (pounds per acre) ercent downy es to an ”1.1.1-1-..- ;. Lmostabl shedstandnr, auauaiinfeate d- with. -.<39':W_93:9"33:E[a§§:w-1_. ‘ with IPC in the fall at the 5, 10 and 20 pounds per acre rates. IPC gave less control when applied in the Spring. The best control with TC; was obtained in the fall. Very poor control was obtained when the TCA was applied in the Spring. Less than 53 downy brome—grass remained when TCA was applied at 5, 10 and 20 pounds per acre in the fall. The IPC used in tie field trials was the wettable powder form. A considerable amount of the chemical did not go into solution and thus was removed from the actual amount applied to the plot by the sprayer screen. Conseauently, the actual amount of IPC applied to each plot was less than has been reported. All of the sprayed plots yielded more alfalfa than the check plots. Table V shows an analysis of variance of the alfalfa yield of the Sprayed plots. TABLE V ANALYSIS OF VthALCS OF ALFALFA YIELDS FnOM PLOTS SPRAIEDTRITH TCA AND IPC AT VLHIOUS RATSS IN “Hm FALL AND SPRING Source of Variation Degrees of Freedom Mean Square Total b7 23.37ww heplications 2 2.22““ Spray 1 0.23pm Time 1 14.05" hate 3 0.25 Interactions Spray X Time 1 0.67 Spray X hate 3 0.06 Time X Rate 3 0.75 Spray X Time X hate 3 0.80 Error 30 8.38 *% Highly significant. 29 In regard to the effect upon the alfalfa yields by the type of Spray, rate of application, time of application, and their interactions only the time of application was highly significant. The fall application yields were significantly higher than the spring application yields. SUL‘JI‘LDJLY 30 SUMMARY The chemical control of downy brcme—grass in an established alfalfa field was attempted by applying IPC and TCA. Four different experiments were conducted to help determine at what rate and at what time of the year to apply the herbicides to obtain the best control. 1. 2. 10. 11. TCA controlled downy brome-grass best when applied at seeding time. TCA at 10 pounds per acre controlled the total dry weight and the dry weight per plant of downy brome—grass better than the 5 pound rate. . TCA at 10 pounds per acre controlled the number of downy brome- grass plants better than the 5 pound rate except at one stage of growth. Downy brome-grass seeds germinated at high temperatures (85 degrees Fahrenheit). Old downy brome-grass seeds germinated best at the higher temperatures (85 degrees Fahrenheit), while the new downy brome—grass seeds germinated best at the lower temperatures (55 degrees Fahrenheit). . Downy brome-grass seeds have a dormancy period. The extent of dormancy of the downy brome-grass seeds is directly connected with the stage of maturity that the seeds are harvested. The immature seedshave more dormancy than the mature seeds. . The dormancy in mature seeds is broken in 50% of them within twenty days after harvest. CA and IPC applied in the fall controlled the downy brome- grass better than the Spring applications. Spring applications of the herbicides significantly decreased the alfalfa yields when compared with the fall application. 12. 13. 1h. 17. 18. 31 IPC controlled the downy brome-grass better than TCA. IPC at 5, 10 and 20 pounds per acre applied in the fall gave excellent control of the downy brome-grass. IPC at 10 and 20 pounds per acre applied in the spring gave excellent control of the downy brome-grass. TCA at 20 pounds per acre applied in the fall approximated excellent control of the downy brome-grass. Slight alfalfa injury was observed when IPC and TCA were applied at 20 pounds per acre. Spring applications of IPC stunted the downy brome-grass. Further experiments should be conducted on the time to apply the herbicides in the fall. TCA and IPC should be applied at 1, 2, 3, h and 5 pounds per acre on various dates ranging from the time the first cutting of hay is made until the latter part of November. Chloro IPC should be used in some experiments to determine if it could be used rather than the wettaole powder IPC. B IBLIC GIULPEY 32 BIBLIOGRAPHY Darlington, H. T., Bessey, E. A., Megee, C. R., and Grigsby, B. H., "Some Important Michigan Needs", Michigan Agricultural Experi- ment Station, Special Bulletin 30h (Second Revision), May 1951. Finnerty, D. H., Klingman, D. L., and Shafer, N. E., “Effects of Herbicidal Treatments Used for the Control oflfeedy Bromes", Nebraska Agricultural Experiment Station, Report of North Central heed.Control Conference, 1950. Grigsby, B. H., Churchill, B. R., Hamner, C. L., Carlson, R. F., "Chemical'Weed Control", Michigan State College Extension Circular 211; (First Revision), May 1950, Megee, C. R., “Zild Oats or Downy Brome", Michigan Agricultural Experiment Station Quarterly Bulletin, 20:3, February 1938. Miller, J. H., and Dunham, R. S., "The Effect of Herbicides on Established Legumes", Science Journal Series of Minnesota Agricultural hxperiment Station, Paper No. 2738, Report of North.Central'Weed Control Conference, 1951. Peters, R. A., and‘Willard, C. J., "Control of Quackgrass in Established Alfalfa Using Sodium TCA", Ohio Agricultural Experiment Station, Report of North Central ideed Control Conference, 1951. Shafer, N. 3., "Use of Herbicides for Annual heed Control in Alfalfa", Nebraska Agricultural Experiment Station, Report of North Central heed Control Conference, l9h9. Shafer, N. E., and Finnerty, D. h., "Toxicity of Five Chemicals Applied as Soil Treatments", Nebraska Agricultural Experiment Station, Report of North Centrallfeed Control Conference, 1950. Hatson, A. J., "Effect of Sodium TCA and DNOSBP on Downy Brome-Grass (Eromus tectorum) in Established Alfalfa", Dow Chemical Company, South Haven, Michigan, Report of North.Central'heed Control ConferenCe, 1950. .‘ .*\.‘ .~. ‘ K 0. Link; 5...... km Au}. (if. MW? 1a.. b. .. .Lovgn I‘Lrlfinkn'm . . Awéut . in H... o . (>4 v \ v\.1 . 1 o 1 L . J . J . WNL. L . . .L I .l ‘ I“ s 2'4 u I . .‘l: .. . L. . .c an I. .9 r a . h o n . . . .k I.. .. ; u n I. . ..~ 1...”. I . ’ ‘\ 1|.f \.\..\ . t . | . \. t u. _ I n \ 0.. n . | . . . o ‘ r A 1. I u H .. K v . \ n n ' I . O . - .1 -. x -1 . . .~ g l I a ..X n n. -1 . I I. b I 0‘ I V” . . . . ..nr. 1 ’ . a r. . \ ,._ \ ‘ ( (I . . :K. I I u. . 1 .. . a . . . u ’I l vol ' I — - In I (‘-l I n ‘ O . I s n - o . In & I O . w c . o i I .I‘ . I. l I. N l U I I ‘1 q '5 l l '1'! c I v - . I 1 III . y t . l . I I i .r . t .. n - o I I - - . . . o L . I 1 I I 2 . n J. 4 l . - 0 . \\ o . . . . (1 . . :1 r0- ‘ r ' nI - I . . I n . a \o v v‘ . v ‘1 n... n 0 »r- I‘I rl r n. t . 0 l I v 1‘ I a _ J a \ . v “ l' J‘- . O O I‘ll.‘ L In \ x I I l. 1" ~\ _ a o I . \ L. O I ll \1 \ \1 u x . . x l v - . \\n u). ; ; . .- \4n 1-. . II n I ( . I. . In ..I. . 1 AL I O Q \ M“ .l h | o ’ - I 1 1‘ u . . f . . l u \l / h' _ f‘ n .l v .5 I o 0 I f f 0 Pill C - I u U V a .0 . A a \7 I “7 . a In . s f s. n \ . h I 1.... I . \ I..\l I n . . . n\ Q .. \\ . x ‘n a v./ . I .\ r ‘8 -r - . \ r .n r .1 I. (In! .0 6 o . Q n . n .1 v.‘ . .\ u .I l. .. I n K . nV\. \ . I 1V .o . J u M n a a u .n ‘ .0 T mmM'E‘flliflilflfljflfllaflifllfl'Es “7:11:77 71’; m 9