The activity of TH 6040, a chitin synthesis inhibitor, was determined against velvetbean caterpillar, Anticarsia gemmatalis Hübner, and other soybean defoliators in field tests in Georgia, South Carolina, and Brazil. Single applications at rates as low as 75 g AI/ha afforded adequate initial and excellent residual control of A. gemmatalis and some suppression of low populations of Plusia spp. Two applications at higher rates gave significant control of soybean looper, Pseudoplusia includens (Walker), and showed promise against green cloverworm, Plathypena scabra (F.), and Mexican bean beetle, Epilachna varivestis Mulsant. Populations of geocorids and nabids were lower in 1 test, possibly because of insecticidal activity, scarcity of prey, or both

da Silva, R. F. P.

Heinrichs, E. A.

Todd, J. W.

Turnipseed, S. G.

English

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications: Department of Entomology Entomology, Department of 1974 Response of Soybean Insects to Foliar Applications of a Chitin Synthesis Inhibitor TH 6040 S. G. Turnipseed Clemson University E. A. Heinrichs EMBRAPA/USAID, eheinrichs2@unl.edu R. F. P. da Silva Instituto Pesquisa Agronomicas J. W. Todd University of Georgia Follow this and additional works at: https://digitalcommons.unl.edu/entomologyfacpub  Part of the Agriculture Commons, and the Entomology Commons Turnipseed, S. G.; Heinrichs, E. A.; da Silva, R. F. P.; and Todd, J. W., "Response of Soybean Insects to Foliar Applications of a Chitin Synthesis Inhibitor TH 6040" (1974). Faculty Publications: Department of Entomology. 834. https://digitalcommons.unl.edu/entomologyfacpub/834 This Article is brought to you for free and open access by the Entomology, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications: Department of Entomology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.    Published in Journal of Economic Entomology 67:6 (1974), pp. 760–762; doi: 10.1093/jee/67.6.760 Copyright © 1974 Entomological Society of America. Published by Oxford University Press. Used by permission. Submitted June 24, 1974.   Response of Soybean Insects to Foliar Applications of a Chitin Synthesis Inhibitor TH 6040   S. G. Turnipseed,1 E. A. Heinrichs,2 R. F. P. da Silva,3 and J. W. Todd4  1. Professor of Entomology and Economic Zoology, Edisto Experiment Station, Clemson University, Blackville, South Carolina, USA 2. Projeto Nacional da Soja, EMBRAPA/USAID, Porto Alegre, Rio Grande do Sul, Brazil 3. Engenheiro Agronomo, Instituto Pesquisa Agronomicas, Secretaria da Agricultura, Porto Alegre, Rio Grande do Sul, Brazil 4. Assistant Professor of Entomology, Coastal Plain Station, University of Georgia, Tifton, Georgia, USA  Abstract The activity of TH 6040, a chitin synthesis inhibitor, was determined against velvetbean caterpillar, Anticarsia gemmatalis Hübner, and other soybean defoliators in field tests in Georgia, South Carolina, and Brazil. Single applications at rates as low as 75 g AI/ha afforded adequate initial and excellent residual control of A. gemmatalis and some suppression of low populations of Plusia spp. Two appli-cations at higher rates gave significant control of soybean looper, Pseudoplusia includens (Walker), and showed promise against green cloverworm, Plathypena scabra (F.), and Mexican bean beetle, Epi-lachna varivestis Mulsant. Populations of geocorids and nabids were lower in 1 test, possibly because of insecticidal activity, scarcity of prey, or both.  Reports by van Daalen et al. (1972) and Wellinga et al. (1973) indicated that 1-(4-chloro-phenyl)-3-(2,6-diflourobenzoyl) urea (TH 6040) interfered with cuticle deposition in cer-tain insects. Neal (1974) reported that TH 6040 controlled alfalfa weevil, Hypera postica (Gyllenhal), in small field plots. T U R N I P S E E D  E T  A L . ,  J O U R N A L  O F  E C O N O M I C  E N T O M O L O G Y  6 7  (1 9 7 4 )  2 Foliar activity of TH 6040 against the velvetbean caterpillar, Anticarsia gemmatalis Hüb-ner, and other soybean insects was observed in field plots in 1973 at Blackville, South Car-olina, and Tifton, Georgia (USA), and in 1974 at Porto Alegre, Rio Grande do Sul, Brazil.  Materials and Methods  We compared TH 6040 with carbaryl in plots replicated 4 times in a randomized block design at Blackville (Test 1) and Porto Alegre (Tests 2 and 3). In Test 1, two separate appli-cations were made to “Hutton” soybeans ca. 1 m high in plots 6 rows (96.5 cm centers) wide by 12.2 m long separated by 2 untreated rows. A knapsack sprayer was used which delivered 77.5 liters/ha at 3.5 kg/cm2. Counts were made by beating 2.4 m of row over a ground cloth and recording live insects from the cloth (Shepard et al. 1974). Percent defo-liation was estimated independently by 2 people from the middle 4 rows of each plot. In Test 2, methods were similar except the “Davis” variety was used; plots were 4 rows (60 cm centers) wide by 5 m long; 800 liters/ha were delivered; a single application was made; and 2 m of row were counted. In Test 3, the Davis variety was used; plots were 5 rows (60 cm centers) wide by 10 m long; 800 liters/ha were delivered; a single application was made; and 4 m of row were counted. At Tifton (Test 4), TH 6040 was applied at 562 g AI/ha to Hutton soybeans ca. 1 m high in 2 strips 16 rows (91.4 cm centers) wide by 60.9 m long using a high clearance sprayer with 3 nozzles/row which delivered 130.9 liters/ha at 2.8 kg/cm2. Separate applications were made on Aug. 22 and Sept. 5. Treated strips were com-pared with paired checks by counting 2.4 m of row with a ground cloth at 8 locations/strip.  Results  Test 1, Blackville Two applications of TH 6040 at 281 or 562 g AI/ha (Table 1) afforded excellent control of the velvetbean caterpillar for 35 days posttreatment (Aug. 24–Sept. 25). Carbaryl gave ex-cellent initial control but residual activity was inadequate. Both rates of TH 6040 caused significant reductions in numbers of the soybean looper, Pseudoplusia includens (Walker), 14 days posttreatment (Sept. 4). Although differences were not significant, numbers of lar-vae of the Mexican bean beetle, Epilachna varivestis Mulsant, were lower in TH 6040–treated plots after 35 days (Sept. 25). There were no significant differences in yields among treat-ments, even though defoliation was ca. 5% in the TH 6040 plots compared with ca. 35% in carbaryl or check plots. Numbers of geocorids and nabids 35 days posttreatment (Sept. 25) were significantly lower in TH 6040 plots and intermediate in carbaryl plots compared with untreated checks.   T U R N I P S E E D  E T  A L . ,  J O U R N A L  O F  E C O N O M I C  E N T O M O L O G Y  6 7  (1 9 7 4 )  3 Table 1. Activity of TH 6040 and carbaryl against soybean insects, Test 1, Blackville, South Carolina, 1973a Treatment Rate/ha (g AI)b Avg. no. alive in 2.4 m row (ground cloth) % Defoliation (10/10) Yield (kg/ha) Anticarsia gemmatalis  Pseudoplusia includens Epilachna varivestis larvae (9/25) Geocorids (9/25) Nabids (9/25) 8/24 9/4 9/25  8/21 9/4 TH 6040 E.C. 281 0.0 a 0.3 a 0.3 a  1.0 ab 8.3 a 0.3 a 3.8 ab 3.3 a < 5.0 2,124 a TH 6040 E.C. 562 0.0 a 0.3 a 0.3 a  0.5 a 6.0 a 1.0 a 1.8 a 3.3 a 5.6 2,344 a Carbaryl 80S 673 0.3 a 1.5 a 41.5 b  3.5 b 30.5 b 12.5 a 6.3 b 5.8 ab 35.6 2,110 a Check  8.5 b 11.5 b 54.0 b  3.3 b 25.5 b 12.0 a 18.3 c 9.3 b 33.1 2,110 a a. Means followed by the same letter are not significantlydifferent at the 5% level (Duncan’s multipic range test). Observation dates indicated as month/day. b. Applied as foliar sprays at indicated rates on Aug. 6 and 21.  Tests 2 and 3, Porto Alegre A single application of TH 6040 at 75 g AI/ha (Table 2, Test 2) gave significant initial control of the velvetbean caterpillar and caused 20-fold reductions in its numbers at 20 days post-treatment (Feb. 11). Higher rates of TH 6040 (Tests 2 and 3) afforded similar efficacy against this insect. Carbaryl provided good initial control but was not effective 20 days after ap-plication (Feb. 11). Populations of Plusia spp. were low but some suppression of their num-bers by TH 6040 and carbaryl was observed in Test 3.  Table 2. Activity of TH 6040 and carbaryl against Anticarsia gemmatalis and Plusia spp. on soybeans, Tests 2 and 3, Porto Alegre, R.S., Brazil, 1974a Treatment Rate/ha (g AI)b Avg. no. live insectsc Defoliation (%) Yield (kg/ha) Test 2 (1/22/74)   A. gemmatalis Plusia spp.    1/25 2/1 2/11 (2/1) 2/4 2/28 TH 6040 25W 75 7.5 a 1.0a 1.0 a 5.0 a 7.5 a 8.8 a 3,239 b TH 6040 25W 150 9.0 a 0.8 a 1.0a 3.8 a 6.8 a 8.8 a 3,611 b Carbaryl 80S 250 4.0 a 6.0 a 21.3 b 3.5 a 10.1 a 50.0 b 2,641 a Check  28.8 b 34.3 b 24.3 b 4.0 a 38.8 b 70.0 c 2,172 a Test 3 (2/2/74)   A. gemmatalis Plusia spp.    2/8 2/22 2/8 2/22 2/19 2/28 TH 6040 25W 110 2.5 a 0.5 a 3.8 a 1.8 ab 25.0 a 20.0 a 2,757 b TH 6040 25W 220 0.5 a 1.0a 3.5 a 1.3 ab 26.3 a 22.5 ab 2,509 b Carbaryl 80S 560 0.8 a 20.3 b 2.0 a 0.8 a 23.8 a 41.3 b 2,348 b Check  21.8 b 28.0 b 8.5 b 3.0 b 72.5 b 73.8 c 1,267 a a. Means followed by the same letter are not significantlydifferent at the 5% level (Duncan’s multiple range test). Observation dates indicated as month/day. b. One application as foliar spray: Test 2 on 1/22 and Test 3 on 2/2. c. Avg. no. alive in 2 m row for Test 2 and 4 m row for Test 3.  In Test 2, estimated defoliation 13 days posttreatment (Feb. 4) was near 10% in treated plots and 40% in untreated checks. At 37 days posttreatment (Feb. 28), defoliation reached 70% in checks, 50% in carbaryl-treated plots, and was unchanged in the TH 6040–treated T U R N I P S E E D  E T  A L . ,  J O U R N A L  O F  E C O N O M I C  E N T O M O L O G Y  6 7  (1 9 7 4 )  4 plots. Yields were significantly higher from both TH 6040 treatments than from carbaryl or check treatments. In Test 3, although pretreatment defoliation approached ca. 25%, by 17 days posttreat-ment (Feb. 19) defoliation was 3 times higher in untreated checks compared with TH 6040 or carbaryl plots which were similar. At 26 days (Feb. 28), defoliation levels were 2 times higher in carbaryl and 3 times higher in check plots than in TH 6040 plots which were near 20%. Yields from treated plots were not significantly different and were ca. double the yields of untreated checks.  Test 4, Tifton Although replication was inadequate, Test 4 provided additional evidence that TH 6040 can give almost complete protection of foliage (Table 3). Protection in this test resulted primarily from control of the velvetbean caterpillar, some suppression of soybean looper, and a 3-fold reduction in green cloverworm, Plathypena scabra (F.).  Table 3. Activity of TH 6040 against Anticarsia gemmatalis, Plathypena scabra, and Pseudoplusia includens on soybeans, Test 4, Tifton, Georgia, 1973 Treatmenta Avg. no. alive in 2.4 m rowb   Anticarsia gemmatalis  Pseudoplusia includens  Plathypena scabra   8/28 9/4 9/13  8/23 9/4  8/28 9/4 Defoliation (%) Yield (kg/ha) TH 6040 0.5 0.8 0.0  2.3 5.5  0.8 7.0 2.0 1,591 Check 20.9 78.1 35.6  3.9 10.4  8.1 20.3 75.0 1,281 a. Two applications at 562 g AI/ha on 8/22 and 9/5 b. In 8 locations in each of 2 treated and 2 untreated strips. Observation dates indicated as month/day.  Discussion  In the 4 tests, TH 6040 gave excellent season-long control of velvetbean caterpillar. Ade-quate initial control of this insect was obtained in Tests 2 (3 days posttreatment), 3 and 4 (6 days posttreatment). Single applications in Tests 2 and 3 at low rates (75 and 110 g AI/ha, respectively) were as effective against this pest as higher rates or dual applications. TH 6040 (Test 1) afforded significant control of soybean looper and reduced numbers of Mexican bean beetle larvae. It appeared to suppress loopers and offered promise against green clo-verworm in Test 4. Numbers of geocorids and nabids (Test 1) were significantly lower in TH 6040 than in check plots. These lower numbers may have been due to the direct activity of the material against the predators, a reduction in prey, or a combination of both. TH 6040 showed promise as a good initial and excellent residual material for the control of certain soybean insects. This new inhibitor of chitin synthesis may have particular utility in management systems where velvetbean caterpillar is a major pest species.   T U R N I P S E E D  E T  A L . ,  J O U R N A L  O F  E C O N O M I C  E N T O M O L O G Y  6 7  (1 9 7 4 )  5 Acknowledgments – Technical Contribution No. 1192, Department of Entomology and Economic Zoology, South Carolina Agricultural Experiment Station, Clemson. Published by permission of the director. Research supported in part by the National Science Foundation and the Environmental Pro-tection Agency through a grant to the University of California, and by Agronomia 198/73 Fundacao De Amparo A Pesquisa do Estado do Rio Grande do Sul. The findings and opinions expressed herein are those of the authors and not necessarily of California, the National Science Foundation, or the Environmental Protection Agency.  References Cited  Neal, J. W., Jr. 1974. Alfalfa weevil control with the unique growth disrupter TH 6040 in small plot tests. J. Econ. Entomol. 67: 300–1. Shepard, M., G. R. Carner, and S. G. Turnipseed. 1974. A comparison of three sampling methods for arthropods in soybeans. Environ. Entomol. 3: 227–32. van Daalen, J. J., J. Meltzer, R. Mulder, and K. Wellinga. 1972. A selective insecticide with a novel mode of action. Naturwissenschaften 59: 312–3. Wellinga, K., R. Mulder, and J. J. van Daalen. 1973. Synthesis and laboratory evaluation of 1-(2, 6-disubstituted benzoyl)-3-phenylureas, a new class of insecticides. I. 1-(2J 6-dichlorobenzoyl)-3-phenylureas. J. Agric. Food Chern. 21: 348–54. 

Response of Soybean Insects to Foliar Applications of a Chitin Synthesis Inhibitor TH 6040

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Response of Soybean Insects to Foliar Applications of a Chitin Synthesis Inhibitor TH 6040

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