\ w'—" IMHI i l W 1 l | ‘1 WI “W I ‘ (D—fi\l _.| 1:13 THE EFFECTS OF HERBICFDES, ENSECTSCEDES, Ru YES OF PLANTING, NWROGEN FERTIUZATEON AND BURNENG ON YIELD AND SILVER TOP OCCURRENCE [N CHEWINGS FESCUE Thesis. far fhc Dogm of M. S. MCHiGAN STATE COLLEGE Francis K. McMulian 1954 (HF—5‘5 This is to certify that the thesis entitled THE E’VFECTS OF ERBICDES, IF‘ISECTICIDTIS, RATES OF PD. I‘I'l'IT-IG, NIT RD TEEN FERTEIZATION AND BURI-IING ON YIELD AIID SILVER TOP oocmmams IN CE—EI‘JII‘ES FESCUE presented by Francis K. McMullen has been accepted towards fulfillment of the requirements for #5.;— degree in WS Major professor Date December 6, l95h 0-169 ~.__._-__-’ ...—~ - - THE EFFECTS OF HERBICIDES, INSECTICIDES, RATES OF PLANTING, NITROGEN FERTILIZATION AND BURNING ON YIELD AND SILVER TOP OCCURRENCE IN CHEWINGS FESCUE By Francis K. McMullen 'J‘ AN ABSTRACT 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 Crops m-fl‘fl ‘ ‘ .“. . 'fHE THESIS ABSTRACT An experiment, covering a period of two years, was carried out at East Lansing,.Michigan, using the insecticides Harlate, DDT, and Elfi(benzenehexachloride); herbicides C-IPC and TCA; burning, with and without nitrogen fertilization; nitrogen application; and combinations of the above mentioned chemicals and practices on seed yield and silver tOp occurrence of Chewings fescue, Festuca.ggggg variety commutata. Rates of planting experiments were also included. No significant increase in yield or justifiable decrease in silver tap occurrence, between the means of all treatments and the untreated plots, was obtained the first year. The second year, significant dif- ferences of yield and noticeable differences of silver top occurrence between the means of the following treatments and untreated plots were observed, in order of effectiveness: 1) Burning of stubble in August plus application of nitrogen in August. 2) Burning of stubble in August. 3) Spring application of’C-IPC, (second year yields only). b) Spring application of DDT. 5) Spring application of nitrOgen. No significant differences in yield between the means of rate of plant- ing were obtained the first year. A noticeable decrease in silver tap was Observed in these plots that were seeded at one-half pound per acre the first year. The second year, significant increases in yield and noticeable decreases of silver tap were observed between the means of one-half pound rate of planting and other rates of planting. .343492 _‘.Hg§ti THE EFFECTS OF HERBICIDES, INSECTICIDES, RATES OF PLANTING, NITROGEN FERTILIZATION AND BURNING ON YIELD AND SILVER TOP OCCURRENCE IN CHEWINGS FESCUE By Francis K. McMullen 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 Crops 19Sh 1-H EELS .\- H F5“ TABLE OF CONTENTS Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . 1 Review of Literature . . . . . .1. . . . . . . . . ... . . . 3 MaterialsandMethods.................... 5 Results and Discussion . . . . . . . . . . . . . . . . . .. 9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 Literature Cited 0 O O O O O O O O O .O O O O O O C O O C O 0 2h INTRODUCTION Silver top of grasses has been a problem since the turn of the century, but to date, only limited success has been obtained in its control. Silver tap is characterised by an injury involving the conductive tissue of the plant stem mediately above the tapmost node. The seed bearing head of the plant dries prematurely, becomes silvery in appearance and no seeds are formed, (Figure 1). Leading authorities are still divided in their Opinion as to whether silver t0p is caused by an insect, virus, or fungus. Fergus (10) of Kentucky reports that silver top is caused by two sucking insects whereas Herdison (lb), of Oregon, and Keil (l) , of Pennsylvania state that the disease is due to the combined activities of a mite and a fungus, Fusarim pose. The experiment reported here was set up to study the _ effects of various chemicals, rates of planting, burning, and nitrogen fertilization on seed yield and silver top occurrence in Chewmgs fescue , Festuca rubra variety comtata. «HF-532 \ -Hpgi-éti Figure l . Panicles of Chewings fescue A. Normal B. Silver TOp REVIEW OF LITERATURE Difficulties were experienced when, in 1938, Pennsylvania farmers tried to produce seed of feseue. Low yields obtained were attributed to a disease. Later, Keil (1) suggested the presence of Fusarium 2933 as the possible cause of this condition. Femald and made (5, '21:) have reported tte I'disease" on 32 species of grasses in Massachusetts. In Pennsylvania (1) it has been reported on ten species of grasses. Stewart and I‘bdgkiss (111) reported that the disease was first mentioned in 1875 by Cometock in his 'Syllabus of a Course of lectures." From this time until 1900 the disease was reported by both Fernald (7) and Lintner (3). Since then several workers have made reference to it in this as well as foreign countries. The disease hass'been found in Germany, Finland, Canada and tte United States. Router (11) reported it from Finland and named the disease Weissahrigkeit". Kauffman (18) has shown the disease to be detrimental to grasses in Germany. Osburn (17) has stated it to be cannon in Canada. In the United States the disease has been reported in Maine (7), Nebraska (2, 10), Massachusetts (5), New York (15, 114), ~ Wisconsin (8), Pennsylvania (1) , and Rhode Island. The fungus (Spa—retrichum $3.2) associated with "white beads“ was discovered by Stewart and Hodgkiss (1h) who submitted it to Peck (6) in 1902 for identification. Recently, Wollenweber and Rein (12) (“gets published that 'Sporotrichum pgae" was actually a species of Fusarium. Keil presented evidence toward proving that this fungus is the cause of the disease "white heads' in fescue. (H.253? MATERIALS AND METI'DDS A series of treatments were planned to develop and evaluate con- trol measures for silver tap. Several chemicals were used in addition to the burning treatments and rates of seeding. The following insecticides were used: DDT, 50% wettable. Rate - One and one-half pounds per acre, active ingredient, applied May 15. 1953 and May 13. 1951.. Harlate, 234% Technical. Rate - One 'pound per acre, active ingredient, applied May 15, 1953. One and one-half pounds per acre, active ingredient, applied May 13, 1953. 34-1 , Concentrate benzene hexac hloride) . Rate - Five hundred cubic centimeters per acre applied May 15 , 1953. The remaining two chemical compotmds.were~'herbicides, and consisted of the following: TCA, Dow sodium, 90%. Rate - Ten pounds per acre, acid equivalent, applied April 28, 1953 and November 6, 1953. 0-90, 10% Rate - Five pounds per acre, active ingredient, applied April 28, 1953 and November 6, 1953. The burning treat-ant consisted of burning the grass residue and dead stubble one month after seed harvest. This was accomplished by spreading a thin layer of timotln' hey over the plots to be burned and setting fire to the windward end of the rows. Nitrogen fertilis ation treatments were also applied in the experi- ment. The nitrogen fertilisation progrn consisted of: (“5:915 Ammonium nitrate: April 12, 1953 and April 12, 1951; Ammonium sulfate: August 11, 1953 The rate was 66 pounds of elemental nitrogen to the acre. Five treat- ments using nitrOgen as a component were used in this emerinent. Number one was a 19534951; spring application of nitrogen, at the rate of 66 pounds (elemental) per acre, plus Marlate, (211% technical), applied at the rate of one pound per acre in the spring of 1953, and one and one-half pounds per acre in the spring of l95h. Spring appli- cations of nitrogen were used with each of the fall applications of the following herbicides : 2. C-IPC , five pounds per acre, 10% active ingredient. 3. TCA, ten pounds per acre, 90% acid equivalent. The fourth and fifth treatments used to study fescue seed yield and silver top occurrence included the following: h . Burning of stubble in August plus application of nitrogen in August. 5. Marlate spring application of one and one-half pounds per acre, (214% technical). Nitrogen, spring application of 66 pounds (elemental) per acre . C-IPC , fall application of five pounds per acre, (140% active ingredient). The above mentioned herbicides and insecticides were applied with a knapsack sprayer in liquid form using water as a carrier. The various treatments were applied on a field previously planted at four pounds per acre to Chewings fescue, in September, 1951. Rates of seeding at one-half, one, two and four pounds were included in the original seeding and were considered a part of the eJCperiment. A randomized block design was used, with four replications. A11 plot rows were 30 inches apart and 143 feet long. Rate of seeding plots were seven rows wide, all other plots being four rows wide. Counts for silver top were made both years during the heading stage of the grass. In 1953, silver top heads were counted June 23. This was accomplished by counting and recording the diseased heads in the center ten feet of each second row of each plot. On June 111-15, 1951;, sampling of fescue panicles took place on rows one and four of the chemically treated plots and the controls. Sanpling took place on rows two and six on the ”rate of seeding" plots. Six random samples of panicles were taken per plot at a distance .approfimately, ten feet .apart. The plot sanples were composited and the diseased and healthy panicles were counted and recorded. Percentages of diseased panicles from the plot samples were calculated and recorded. A substantial part (32%) of the tags bearing the numbers of green panicles found in the plot sauples for 1951; was lost, as shown in the tables. The fescue was harvested by hand June 29 and 30 of 1953 , and June 28 , 29, and 30 of 1951:. In 1953 ,forty foot' strips of the two ' center rows were harvested on all chemically treated and control plots. Rows three and five were harvested on the rate of seeding plots. In 1951: the seas procedure was used, with the exception that the harvest rows were shortened by five feet, making their length thirty-five feet . A rasp type thresher was used to thresh the fescue seed on August 12 and 13, 1953, and August 16-18, 195h. To insure complete separation of the seed from the panicles, the straw was run through the thresher twice. Final cleaning consisted of running the sifted seed through a Clipper cleaner (l-B) twice. RESULTS AND DISJUSSION Insecticides, herbicides, nitrogen application, burning, and various combinations of these practices, along with rate of seeding treatments were used on Chewings fescue plots because of the follow- ing six possible reasons: 1. Silver tap of fescue may be caused or transmitted by an insect, and a control can be obtained by eliminating the disseminat- ing agents with the use of insecticides. 2. Silver tap of fescue may be caused or perpetuated by a sod- bound condition existing typically in older stands. This might be eliminated. by thinning the fescue stand with herbicidal treatments or variable rates of seeding. 3. The causal agent of silver top may be lodged on the thrashed strut and dead stubble after harvest time. Burning the harvest refuse would possibly eliminate the causal agent. )4. Silver top seems to be associated with succulent plants. Therefore, more dmage might be noticeable in those plots that were fertilized with nitrogen. 5. Silver top of fescue may be caused by any combination of reasons' 1, 2 or 3 . Therefore a combination of the above treatments might be effective in controlling silver tap. The 1951: yield of Chewings fescue seed was low. At least a part of this low yield probably was due to adverse weather conditions as shown in Table I. 10 TABLE I TOTAL MONTHLY PRFBIPITATION OF APRIL, MAY, AND JUNE 01‘ 1953 AND 1951;, as acumen WITH A THIRTY YEAR AVERAGE, 1921-1950 (East Lansing Weather Bureau, East Lansing, Michigan) Precipitation m __ East Lansing, Michigan; Month 30 Year Average 2 1921-1950 1953 19su ; April 2.83 2.88 2.75 i g, May 3.75 1.75 1.52 g June 3.37 2.87 11.89 * The average monthly precipitation in May of 19511 was less than one-half of the thirty year average of that month. or the 1.52 inches of rainfall acctmulated during this month, only a small portion occurred during the first 28 days. This seriously reduced the yield of Chewings fescue seed which was harvested one month later. Because of the low precipitation in May of 1953, the yield that year was lowered, but not to the ease extent as in 19511. Table II shows the effect of Harlate, DDT, Bil, and combined treatments of Marlate, nitrogen and C-IPC on yield of seed, in com- parison to the untreated plots. Table II shows that there were no significant differences in yield during 1953 with any treatment. In 1951:, the highest yield was obtained from tin plots sprayed with DDT. Plots treated with Marlate gave yields in both years that varied only slightly from 11 TABLE II NET CF INSEITICIDES AND COMBINED TREATMENTS 0N YIELD OF OPENINGS FESSUE AS CCMPARED WITH UNTREATED PLOTS Aver age Yield (Pounds Per Acre) Treatment 1953 1951: Check ‘ . 2117 136 Narlate (spring of 1953 and 195A) 262 156 nor (spring of 1953 and 1951;) 258 n 219 an (spring of 1953)1 ' 257 --- Marlate (spring of 19514) magmas?“ m .- L. S.'D. at 5% level 38 55 ‘MD-“5~“— '— f Not included in 1951; 2 Not included in 1953 the untreated plots. The one-half pound per acre increase in spray application of Marlate in 1951; gave no appreciable results over the previous application. No significant differences in yield were obtained from plots treated with E41. The combined treatment of Marlate, nitrogen and C-IPC resulted in stands that were very thin, poor of vigor and extremely low in yield. The harbicide injured the plants to such an extent that the stand was greatly reduced. Table III shows the effect of spring and fall treatments of TCA and C-IPC on the yield of Chewings fescue, in conIparison with un- treated plots . 12 TABLE III EFFEXJT OF IERBICIDE TREATMENTS ON YIELD OF CHEWINGS F ESCUE AS CWARED WITH UNTREATED PLOTS _ Average Yield #(Pounds Per Acre) Treatment .1 - A 1953 195b__ ‘ Check 21:7 136 TCA (spring of 1953) 190 196 TCA (fall of 1953)1 --- ‘ 52 C-IPC. (spring of 1953) 68 222 C-IPC (fall of 1953)1 --.. 25 L. S. D. at 5% level 38 55. 1 Not included in 1953 Fall. treatments of both TCA and C-IPC resulted in a very decided reduction in yield. Again, as in the combined treatment of Marlate, nitrogen and C-IPC, plants were severely burned by the herbi- cide, and at first the plots appeared to be a total loss. However, a significant increase in yield was obtained the second harvest year following spring~ application. This is in strildng contrast with the extremely poor yield in 1953. In 19511, no significant differences in yield were obtained between the spring treated plots of TCA and C-IPC, and the plots treated with DDT. This is shown in Figure 2. . -5- .ml‘— 061* A . t ‘| 7 ll '1—.__-.'“"" p . .._ t 2 3 300 -[ 250- 200 150 100 Yi eld (Pounds Fer dare.) 50 D E F Treatment Figure 2 . Average yield comparison of .insecticide and herbicide treatments on Chewings fescue. 13 Treatment 3 : A. Check B. DDT C. 8141 D. Mariate E. TCA (spring) Fe TCA (fall) Ge C-D’C (Spring) H. C-IPC (fall) 111 Table IV shows the effect of nitrogen, burning, and the combined treatments, nitrogen with Marlate, nitrogen with C-IPC, nitrogen ' with TCA, and nitrogen with burning on the yield of Chewings fescue seed, in comparison with untreated plots. TABLE IV EFEET OF CULTURAL AND COMBINED PRACTICES 0N YIELD OF CWINGS FESSUE AS COMPARED WITH UNTREATED PLOTS v '— v Average Yield (Pounds Per Acre) Treatments ; __ 1953 l95h Check 2h? 136 Nitrogen (spring of 1953_and 195h) 237 210 Burning (August of 1953)1 --- 269 Burning (August) and Nitrogen (August of 1953)1 --- 293 Harlate (spring) and Nitrogen (spring of 1953 and 195k) 2L2 173 TCA (fall of 1953) and Nitrogen (spring of 19511)1 --- 7h C-IPC (fall of 1953) and 1 - Nitrogen (spring of l95h) --- 12 L. S. D. at 5% level 38 55 ‘— — 1 Not included in 1953 No plot yielded significantly more than the check, in 1953. In 19511, the highest yield obtained was from burning of stubble in August after harvest, plus nitrogen application in August . Burning in August alone and nitrogen application alone also gave significant yield increases in comparison with the ,untreated plots. There was also a significant difference between burning in August plus nitrogen treat- ment, and nitrogen application alone . Plots burned in August and fertilized with nitrogen yielded more than those spring treated with - . :rrfi , } C-IPC. TCA. and DDT. The plots treated with C-IPC plus nitrogen, and :; TCA plus nitrogen gave extremely low yields, (Figure 3). Again, as illustrated previously, the herbicide burned the plant to such an ex— ' .’ 1W”. ._ ‘9'.ng 9.1 .1“. tent that many plants were lost and the stand was thinned considerably. The treatment, Marlate plus nitrogen gave a yield comparable to that of the untreated plots. 9 Figure b shows the effect of one-half pound, one pound, two pounds, and four pound rate of planting per acre on yield. In 1953, yields were approximately the same regardless of rate of seeding. In 1951:, seed yields decreased as rate of seeding in- creased. During this year, the plots burned in August plus nitrogen significantly out-yielded the one-half pound rate of seeding by 81 pounds, and the one pound rate by 89 pounds (per acre). This would indicate that higher yields might have resulted if the treatment burning plus nitrogen could have been applied to a lighter rate of seeding. Table V shows the effects of insecticides, herbicides, burning, thgen, and the nitrogen—Marlate combined treatment on silver tOp occurrence in 1953. O .4. . 300 ‘A 250* 8%) 150 Yield (Pounds Fer acre) H 8 U1 0 Figure 3. L Treatment Average yield comparison of cultural and combined practices on Chewings fescue. MW? 16 Treatment: A. B. C. D. E. F. G. H. Check Burning Burning and nitrogen Nitrogen Nitrogen and Marlate Nitrogen and TCA Nitrogen and C-IPC Nitrogen, Marlate and C-IPC an 1 }. ' “71-7; p‘ 11k.) I‘ll A ‘I‘ 7“ Jun‘ Yield (Found: Fakccrc) 300 ‘ 250 200 150 100 50 Figure ’4 . 1? - 1953 D 1951: Rate 0: Seeding : A. One-half pound per acre B. One pound per acre f“ C. No pounds per acre ' D. Four pounds per acre 8 .a- 45"... .4. Rate Average yield comparison of rate of planting experiment on Chewings fescue. TABLE V mm OF INSECTICIDES, HERBICIDES, NITROGEN FERTILIZATION, BURNING AND NITROGEN comm TREATMENTS ON SILVER TOP CBCURRENCE OF CHEWINGS FEEZUE AS COMPARED WITH THE UNTREATED PLOTS IN 1953 18 ' "’"5‘ , I ,‘_ —._.—. .m..._-—‘ yup-D 1953* Treatment Silver Top Occurrence Check 36 Harlate (spring of 1953 and 19511) 21. DDT (spring of 1953 and 19511) 22 Ian-1 (spring or 1953) 21 Ton (spring of 1953) 38 C-IPC (spring of 1953) 5 Nitrogen (spring of 1953 and 19511) 39 Harlate (spring) and Nitrogen (spring of 1953 and 19511) ‘ 28 * Actual count of silver tap panicles, per ten foot row. with the exception of the plots treated in the spring with C-IPC, no noticeable difference existed in the amount of silver top between the means of all treatments and the untreated plots in the first year. Although the 1953 count of the diseased heads were low in the plots treated with C-IPC in the spring, it must be noted that the yield of seed was also extremely low, as was indicated by the near loss in stand. Table VI (shows the effect of one-half pound per acre, one pound per acre, two pounds per acre, and four pounds per acre rates of seeding on silver tap occurrence of Chewings fescue in 1953. ‘ .(gu' v..-.-‘-i ii A.. v 19 TABLE VI mec'r OF RATES OF PLANTING ON SILVER TOP OCCURRENCE OF CHEWINGS FESCUE IN 1953 1953* Rate of Planting Silver TOp Occurrence One-half pound per acre 12 ‘ One pound per acre . 37 Two pounds per acre 26 2 Four pounds per acre 25 . L. * Actual count of silver tap panicles, per ten feet of row. The most effective rate of planting from the standpoint of silver t0p control was that of the lightest seeding. Other rates showed little promise of control . Table VII shows the effects of insecticides, herbicides, burning, nitrogen and nitrogen combined treatments on silver tap occurrence, in comparison with the untreated plots in 1951:. Plots burned in August plus nitrogen application in August; burning in August; spring application of DDT ; and spring applic ation- of C-IPC gave a very effective control of silver top. Because of the extremely low seed yield obtained from the plots treated in the spring with C-IPC in 1953 (Table III) , the treatment must be con- sidered as economically unsound. The combined treahuent of Marlate , nitrogen and C-IPC was omitted-because of missing data. TABLE VII EFFECT OF INSECTICIDES, HEREICIDES, NITROGEN FERTILIZATION, BURNING, AND NITROGEN cmBINED TREATMEVTS ON SILVER TOP OCCURREVCE OF CIENINGS RESCUE AS COMPARED WITH THE UNTREATED PLOTS IN 19511 19511 Silver TOp Occurrence otal ercent Treatment Beads Silver TOp Silver Tap Collected Heads Heads Check 593 51 7.7a Narlate (spring of 1953 8: 19511). 667 ’49 6.6a DDT (spring of 1953 a 1951;) 510 . h 0.68 TCA (spring of 1953) 7116 1611 17.9“ TCA (fall of 1953) 900 282 26.98 mm (spring of 1953) 39h b . 0.9b C-IPC (fall of 1953) 559 75 12.8 Nitrogen (spring of 1953 8: 1951:) 716 . 78 10.6 Burning (August of 1953) 1371 7 0.6b Burning (August) and a Nitrogen (August of 1953) 1053 6 0.6 ' Marlate (spring) and b Nitrogen (spring of 1953 8: 19511) 6511 65 10.8 TCA (fall of 1953) and Nitrogen (spring of 1951:) 629 167 23.1.;£1 C-IPC (fall of 1953) and b Nitrogen (spring of 19511) 620 133 21.5 a Only three replications used h Only two replications used 21 Table VIII shows the effect of seeding one-half pound, one, two and four pounds per acre on silver tOp occurrence of Chewings fescue in 195A. TABLE VIII WRIT OF RATES OF PLANTING ON SILVER TOP OCCURRENCE OF CHEWINGS FESCUE IN 195h Silver Tap Occurrence Total Pércent Rate of Planting Beads Silver Tap Silver TOp Collected Haads Heads . #7 * One-half pound per acre 923 35 3.h One pound per acre 939 8b 9.8 Two pounds per acre 676 69 10.2* Four pounds per acre . 671 I 58 8.2* * Only three replications used The most effective rate of planting from the standpoint of silver top control was that of the lightest seeding. The seed yield from this rate of seeding was also significantly higher, (Figure 1:) . Other rat-es showed little promise of control. '. W . 2..-. ‘- a V 1 y... ”a! .s..' 9...“? a.“ v {VI 7 “L- SUMMARY 1. The effects of EDT (50% wettable); Marlste (211% technical); EH-l (concentrate); TCA (Dow sodium, 90%); C-l'PC (110%); nitrogen (66 pounds elemental); burning, and combinations thereof on seed yield and silver tOp occurrence on Chewings fescue were studied. 2. The effects of sewing one-half, one, two, and four pounds of . seed per acre on seed yield and silver tOp occurrence were also studied . 3. Yields of all plots were low, chiefly due to climatic condi- tions. In general, the best yields were obtained from the 1953 harvest . h. No significant increase in yield between the means of all 22 treatments, including rates of planting, and the untreated plots were obtained the first year. 5. The second year, significant increases in yield and noticeable decreases of silver tOp occurred between the means of the following treatments and untreated plots in order of effectiveness: a) Burning of stubble in August plus application of nitrogen in August. b) Burning of stubble in August. c) Spring application of C-IPC, (second year yields only). d) Spring application of DDT . e) Spring application of nitrogen. 23 6. With the exception of the burning treatment, burning coupled ‘Hith nitrogen gave seed yields that were significantly higher than any other treatment, treatment combination, or rate of planting. 7. Treatments which included TCA or C-IPC, in the spring of the harvest year, resulted in a very decided reduction in vigor and seed yield that year. 8. The lightest rate of planting (one-half pound per acre) was the most effective in controlling silver tOp and increasing yield of seed. This varied inversely as the rates were increased. 9. Higher yields and more effective silver tOp control might have Jaesulted if the burning and nitrogen treatment could have been applied to a lighter rate of seeding. 1i. ES. 5?. IL). ll. 12. 1h. 15. 17. 2h LITERATURE CITED Keil, H. L., White Heads of Grasses. A Dissertation, Dept. of Bot. Sch. of Agr., Pa. 3. Coll. l9h6. Heald, F. D., The Bud Rot of Carnations. Nebraska Agric. EXp. Sta. Bul. 106:1-2h. 1908. Lintner, J. A., An Unknown Grass Pest. New York State Mus. Nat. Hist. j ‘i Hardison, J. R., Personal letter to Author dated June 21, 195h. Fernald, H. T. and Hinds, W. E., The Grass Thrips. Mass. (Hatch) i Agric 0 C011 0 B111 0 67:1‘9 o 1900 o 5......le Peck, C. H., Report of the State Botanist. N. Y. State Mus. Bul. 67:29. 1903. Fernald, C. H., Grasses of Maine. Rept. Sec. Maine Bd. Agric. l88hz233. 1885. . Fluke, C. L., Mirid Plant Bug threatens Bluegrass Crop. Wisconsin AgriCo up. Sta. Bul. 1‘56329‘300 19M. Fergus, E. N., Personal letter to Author dated May 19, 195k. ‘Wolcott, R. H., A,Mite Accompanying the Bud-rot of Carnations. Neb- raska Agric. Exp. Sta. Bul. 103. 1908. Renter, E. Ueber die Weissahrigkeit der Wiessengraser in Finland. Ein Beitrah zur Kenntnie ihrer Ursachen. Acta Soc. Fauna et Flora Fenncca. 19:(l):1—136. 1900. (Abst. in Zeitschr. f. Pfl. Krankh. 11:250-293). “kallenweber, H. W. and Reinking, 0. A., Die Fusarien, ihre Beschreib— ung, Schadwirkung und Bekampfung. Parey (Berlin). 1935. fitewert, F. C. and Hodgkiss, H. E., The Sporotrichum bud rot of Carn- ations and the silver top of June grass. N. Y. (Geneva) Agric. Emp. Sta. Tech. Bul. 7. 1908. Horsi‘ali, J. G., A Study of Meadow Crop Diseases in New York. New ‘York (Cornell) Agric. Emp. Sta. Memoir 130:116. 1930. Osborn, H., Silver top in Grass and the Insects which may Produce it. Canadian nit. 23:93-96. 1891. 25 18. Kaufman, 0., Die Weissahrigkeit der Weissengraser und ihre Bekamp- fung. In Arbeiten aus der Biologischen Reishsanstalt fur Landund Forstwirtschaft. 13(5) :1197-569. 1925. 21;. Hinds, W. E., The Grass Thrips. Massachusetts Agric. Coll. Rept. 37: 83-105. 1900. ""71111117111111Hangmanu‘m“