Insect Pests Of Soybean Research Articles

Antibiosis of forage soybean as an ecological alternative for the control of corn earworm

The present study is the first to document some antibiosis type of resistance in forage soybeans. The production of forage soybean is increasing in the United States where about 500 000 acres are now grown annually in various soybean growing areas. However, production is limited by the corn earworm Helicoverpa zea Boddie, which is a major insect pest of soybean. An in vitro study of field grown soybean leaves was conducted to select forage soybean genotypes for antibiosis type resistance to corn earworm. The feeding tests were conducted on excised leaf material from a randomized complete block design. The results showed significant differences in the weight of corn earworm larvae, which were allowed to feed on different genotypes of fodder soybean. The mean larval weights on genotypes Tara, 7P116 and 8 GH 85-2 were 245.8, 242.1, and 169.3 mg, respectively. These genotypes were found to be most susceptible to corn earworm while the tall growing vegetable cultivar Moon Cake with the mean larval weight of 94.8 showed some antibiosis types of resistance.

Effects of insecticidal treatment on the Yield and Control of major Insect Pests of Soybean (<i>Glycine max</i> (L.) Merrill) in South-eastern Nigeria

Field experiments were conducted in 1995 and 1996 at Umudike southeastern Nigeria to compare the effectiveness of lindane, cypermethrin, deltamethrin and dimethoate in the control of the major insect pests and yield of soybean. The major insect pests found infesting soybean at 26 to 56 days after planting (DAP) in all the insecticidal treatments were the defoliators, Monolepta duplicata Sahl and Ootheca mutabilis Sahl while the stink bugs, Nezara viridula Linnaeus and Aspavia armigera Fabricius attacked soybean from 56DAP to 86DAP, respectively. During both years, it was found that the insecticides significantly (P Mantis religiosa L. (Mantidae). It was also found that the insecticides significantly (P Int. J. Agric. Rural Dev. , 2003, 4: 100-109

Management of insect pests of soybean: effects of sowing date and intercropping on damage and grain yield in the Nigerian Sudan savanna

Field trials were carried out during the 2001–2002 cropping seasons at Maiduguri, Nigeria, to determine the effects of defoliation and pod damage by insect pests on grain yield of soybean. The factorial experiments consisted of four sowing dates (31 July, 7, 14 and 21 August in 2001 and 21 and 28 July and 4 and 11 August in 2002), four cropping patterns of millet and soybean (3:1, 2:1, 1:1 and 0:1) and two cropping systems of millet-soybean (MS) and millet–soybean–groundnut–cowpea (MSGC). The number of insect defoliators and pod sucking bugs were significantly higher in soybean sown on 31 July in 2001 and on 28 August in 2002. The numbers of pod sucking bugs were also higher in pattern 0:1 and in MS system than the other patterns and systems in both the 2001 and 2002 cropping seasons. Grain yields were higher in early sown soybean in 2001 but not in 2002. Percentage defoliation was significantly lower in cropping pattern 1:1 over other patterns in 2001 and in pattern 0:1 in 2002. Percentage pod damage was significantly lower in pattern 1:1 than the other patterns in both the years. Percentage defoliation was significantly higher in MS intercrop system than the other system in 2001. In both cropping seasons, grain yields were significantly higher in the MS intercrop system than in the MSGC system.

Influence of herbicide tolerant soybean production systems on insect pest populations and pest-induced crop damage.

Conventional soybean weed management and transgenic herbicide-tolerant management were examined to assess their effects on soybean insect pest populations in south Georgia in 1997 and 1998. Soybean variety had very little impact on the insect species observed, except that maturity group effects were observed for stink bug, primarily Nezara viridula (L.), population densities on some sampling dates. Stink bugs were more abundant on the early maturing varieties in mid-season. Velvetbean caterpillar, Anticarsia gemmatalis Hübner, potato leafhopper, Empoasca fabae (Harris), and grasshoppers Melanoplus spp. were more numerous on either conventional or herbicide-tolerant varieties on certain dates, although these differences were not consistent throughout the season. Soybean looper, Pseudoplusia includens (Walker), threecornered alfalfa hopper, Spissistilus festinus (Say), and whitefringed beetles, Graphognathus spp , demonstrated no varietal preference in this study. Few weed treatment differences were observed, but if present on certain sampling dates, then pest numbers were higher in plots where weeds were reduced (either postemergence herbicides or preplant herbicide plus postemergence herbicide). The exception to this weed treatment effect was grasshoppers, which were more numerous in weedy plots when differences were present. In post emergence herbicide plots, there were no differences in insect pest densities between the conventional herbicides (e.g., Classic, Select, Cobra, and Storm) compared with specific gene-inserted herbicide-tolerant materials (i.e., Roundup and Liberty). Defoliation, primarily by velvetbean caterpillar, was different between soybean varieties at some test sites but not different between herbicide treatments. We did not observe differences in seasonal abundance of arthropod pests between conventional and transgenic herbicide-tolerant soybean.

Influence of Herbicide Tolerant Soybean Production Systems on Insect Pest Populations and Pest-Induced Crop Damage

Conventional soybean weed management and transgenic herbicide-tolerant management were examined to assess their effects on soybean insect pest populations in south Georgia in 1997 and 1998. Soybean variety had very little impact on the insect species observed, except that maturity group effects were observed for stink bug, primarily Nezara viridula (L.), population densities on some sampling dates. Stink bugs were more abundant on the early maturing varieties in mid-season. Velvetbean caterpillar, Anticarsia gemmatalis Hübner, potato leafhopper, Empoasca fabae (Harris), and grasshoppers Melanoplus spp. were more numerous on either conventional or herbicide-tolerant varieties on certain dates, although these differences were not consistent throughout the season. Soybean looper, Pseudoplusia includens (Walker), threecornered alfalfa hopper, Spissistilus festinus (Say), and whitefringed beetles, Graphognathus spp., demonstrated no varietal preference in this study. Few weed treatment differences were observed, but if present on certain sampling dates, then pest numbers were higher in plots where weeds were reduced (either postemergence herbicides or preplant herbicide plus postemergence herbicide). The exception to this weed treatment effect was grasshoppers, which were more numerous in weedy plots when differences were present. In postemergence herbicide plots, there were no differences in insect pest densities between the conventional herbicides (e.g., Classic, Select, Cobra, and Storm) compared with specific gene-inserted herbicide-tolerant materials (i.e., Roundup and Liberty). Defoliation, primarily by velvetbean caterpillar, was different between soybean varieties at some test sites but not different between herbicide treatments. We did not observe differences in seasonal abundance of arthropod pests between conventional and transgenic herbicide-tolerant soybean.

Bean pod mottle virus: A Threat to U.S. Soybean Production.

Bean pod mottle virus: A Threat to U.S. Soybean Production.

Evaluation of Soybean Breeding Lines for Corn Earworm Antibiosis

Corn earworm (CEW) (Helicoverpa zea Boddie) is the most serious insect pest of soybean [Glycine max (L.) Merr.] and often has reduced yield in much of the Mid-Atlantic and southern coastal plain of the USA. The objectives of this study were to determine the magnitude of genotype × year interaction (GYI) of antibiosis to CEW and to identify genotypes with stable performance. Thirty-two soybean breeding lines, including two susceptible and one line resistant to CEW, were planted in single row plots arranged in a randomized complete block design in 1996 through 1998 at Petersburg, VA. Petri dish assays were used to evaluate terminal foliage of field-grown soybean for resistance to CEW. Data were analyzed by means of genotype × year analysis of variance (ANOVA) and cultivar superiority performance measure (CSPM). Even though there was considerable variation among the genotypes tested during the three growing seasons, genotypes that ranked consistently either lower or higher in mean CEW larval weight were found. Among the genotypes tested, V89-2623, VS94-42, and VS94-27 generally had the highest CEW larval weight, whereas VS94-11, VS94-12, and VS94-26 were consistently in the lowest CEW larval weight group. Results suggest that CEW resistance of these latter three lines is relatively less affected by environment. They could serve successfully as genetic sources for breeding resistance to CEW. The rank correlation between the combined over year mean ranks and cultivar superiority performance measure value ranks was highly significant (r = 0.985). This suggests that either method of analysis could be suitable in identifying genotypes with stable resistance to CEW. The CEW larval bioassay technique was reliable in separating resistant and susceptible genotypes.

Influência da Adubação Fosfatada - Potássica na Ocorrência de Pragas na Cultura da Soja

O estudo foi desenvolvido para se determinar o efeito da adubação fosfatada-potássica da soja sobre a ocorrência de insetos-praga. Os tratamentos constituíram um fatorial 4 x 4 (quatro doses de fósforo e quatro doses de potássio) com três repetições. Os níveis de fósforo utilizados foram, respectivamente (0, 80, 120 e 160 kg/ha) de P2O5 e (0, 40, 60 e 80 kg/ha) de K2O. Foram realizadas amostragens semanais a partir do estádio V2 da cultura, utilizando-se pano de amostragem. Os resultados indicaram uma tendência de aumento populacional de Piezodorus guildinii (Westwood) para as maiores doses dos nutrientes. A ocorrência de Diabrotica speciosa (Germar) foi correlacionada com alguns nutrientes das folhas.

A field experiment on the effectiveness of spiders and carabid beetles as biocontrol agents in soybean

Abstract1 Spiders and carabid beetles are abundant generalist predators that prey upon insect pests of soybean. A field experiment was conducted to determine the impact of spiders and carabids on soybean yield. Prior to planting, three 7 × 7 m plots were fenced in order to reduce spider and carabid immigration. Carabids that emerged within the plots were not removed, but spiders that ballooned into these predator‐reduction plots or that entered by climbing the fence were removed by pitfall trapping and searching the vegetation. Three unmanipulated, unfenced plots served as the control treatment.2 Densities of spiders on soybean vegetation, and activity‐densities of spiders and carabids determined by pitfall trapping, were c. 75% lower in the spider‐carabid reduction treatment than in control plots. Despite clear differences between treatments in numbers and activity of these major generalist predators, the weight of soybeans harvested did not differ between control and spider‐carabid reduction plots.3 Paralleling the absence of an effect of predator reduction on soybean yield was the absence of any significant difference between treatments in densities of whiteflies (Aleyrodidae), leafhoppers (Cicadellidae), thrips (Thysanoptera), Lepidoptera larvae and herbivorous Coleoptera.4 Our experiment provides no evidence that spiders and carabid beetles at ambient densities affect soybean yield. Low populations of pest species or low predation pressure on soybean pests by spiders and carabids at the ambient densities of this experiment could be responsible for this result.

Effect of planting dates on the Yield and Control of major Insect Pests of Soybean (<i>Glycine max</i> (L) Merril) in Southeastern Nigeria

The effect of planting dates on the yield and control of major insect pests of soybean were studied in the 1995 and 1996 planting seasons at Umudike, Southeastern Nigeria. The incidence of the defoliators, Monolepta duplicata Sahl and Ootheca mutabilis Linnaeus in all the planting dates were earlier (2 weeks after planting, 2WAP) up to 8WAP. However, the stink bugs, Nezara viridula Linnaeus and Aspavia armigera Fabricius were found infesting soybean pods from 8WAP to 14 WAP. The peak populations of the defoliators and stinkbugs were recorded at 4WAP and 10WAP, respectively. The crop planted on August 20 had a significantly (P [IJARD Vol.3 2002: 121-126]

Detection of cry1 genes in Bacillus thuringiensis isolates from South of Brazil and activity against Aanticarsia gemmatalis (Lepidoptera:Noctuidae)

The bacterium Bacillus thuringiensis (Bt) is characterized by its ability to produce proteic crystalline inclusions during sporulation. Cry1 protein has insecticidal activity and is highly specific to certain insects and not toxic to unrelated insects, plants or vertebrates. In this work, the patogenicity of twelve Bt isolates was tested against Anticarsia gemmatalis, one of the most important insect pests of soybeans. Spore-crystal complex was applied to the surface of artificial diets and the mortality of A. gemmatalis larvae was assessed seven days after each treatment. When compared to a control Bt isolate known by its high toxicity to A. gemmatalis larvae, four novel Bt isolates exhibited even higher toxic activities against the insect, resulting in more than 90% mortality. PCR was used to amplify DNA fragments related to known cry1 genes. Bt strains with high toxicity produced expected PCR products of around 280 bp, whereas non-toxic or low toxic strains did not produce any PCR product or showed amplified fragments of different sizes. Toxic Bt isolates also exhibited an expected protein profile when total protein extracts were evaluated by SDS-PAGE.

Efeitos do plantio direto e da consorciação soja-milho sobre inimigos naturais e pragas

Procurou-se avaliar os efeitos do plantio direto e da consorciação soja (Glycine max (L.) Merrill) e milho (Zea mays L.) sobre pragas e inimigos naturais. Os tratamentos constituíram um fatorial 3 x 2 (monocultura de soja, monocultura de milho, consorciação soja-milho x plantio direto, plantio convencional), em blocos casualizados. Os insetos foram amostrados pelo método do pano, rede entomológica, procura visual e armadilha de sucção. Entre os insetos-pragas do milho, Maecolaspis assimilis ocorreu em maior número no sistema de plantio convencional; o mesmo ocorreu com os predadores Cycloneda sanguinea e Doru sp. Por outro lado, M. assimilis e o predador Toxomerus sp. foram mais numerosos na monocultura de milho em relação à cultura do milho consorciado com soja. Dos insetos-pragas da soja, destacaram-se pelo maior número Anticarsia gemmatalis e Diabrotica gracilenta, no sistema de plantio convencional, e o mesmo aconteceu com a espécie da família Trichogrammatidae, enquanto as espécies da família Eulophidae foram mais numerosas na soja sob sistema de plantio direto. Na soja consorciada com milho foi maior o número de insetos-pragas Megalotomus sp. e Maecolaspis sp. e dos inimigos naturais Geocoris sp., Lebia concina, Orius sp., Braconidae e Scelionidae.

Bean Leaf Beetle (Coleoptera: Chrysomelidae) Abundance in Soybean Fields Protected and Unprotected by Shelterbelts

The bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is a major insect pest of soybean in Nebraska and throughout much of the Midwest. This insect overwinters in the adult stage in litter in wooded areas such as shelterbelts. Historically, crop producers have been unsure of the merits of shelterbelts, especially if nearby crops are more likely to be infested by insect pests as a result. In this study, bean leaf beetle adults were sampled during the season by visually counting the number of beetles found on soybean plants early in the season and by sweep net sampling once plants were at the V4 stage (approximately 0.33 m tall). Sampling was done in 1997 and 1998 at the University of Nebraska Agricultural Research and Development Center in Saunders Co. in east-central Nebraska. Beetle counts were compared between shelterbelt-protected and -unprotected fields. In general, bean leaf beetles were more numerous in 1997 than in 1998, with abundance peaks occurring in late-July and early-September in both years. There were significant differences in bean leaf beetle counts from protected and unprotected fields on only three of the 11 and four of the 13 sampling dates in 1997 and 1998, respectively. On the sampling dates when significant differences were found, two of three in 1997 and three of four in 1998 had higher bean leaf beetle abundance in the protected soybean fields. The results of this study indicate a tendency for more bean leaf beetles in shelterbelt-protected soybean fields when differences are found, but beetle numbers were not significantly different between protected and unprotected fields on the majority of sample dates in the two years of this study. This study also reconfirms the presence of two generations of the bean leaf beetle in Nebraska.

Diagnosis of Important Insect Pests of Soybean in Peshawar

Diagnosis of Important Insect Pests of Soybean in Peshawar

Influence of Planting Date and Spacing on the Infestation and Damage to Two Soybean Varieties by Insect Pests at Samaru, Zaria

The influence of planting date and spacing on the level of infestation and damage to soybean by the major insect pests was investigated at Samaru during the 1994 and 1995 wet seasons. The major insect pests of soybean were Ootheca mutabilis Salh, pygomorpha vignaudi Guer, Nezara viridula L., Agonoscelis versicolor Fab and Halydicoris ventralis Dall. Planting date and spacing had no significant effect on percentage defoliation by the insects. The highest percentage defoliations recorded were 13.8 and 15% for 1994 and 1995 respectively, These were below the economic threshold level of 30%. The number of sucking bugs per plot, percentage pod damage per plant, 100 seed weight and seed damage index were not significantly affected by planting date and spacing. There were no significant differences (P < 0.05) between the varieties in terms of insect infestation and damage in both years. However, planting date significantly affects seed yield per hectare. The first plantings had significantly (P < 0.05) higher seed yield than the other subsequent plantings.

Evaluation of Selected Insecticides for Management of Soybean Arthropods in Louisiana, 1995

Abstract The efficacy of selected insecticides for control of soybean insect pests in LA was evaluated in 2 small plot insecticide trials at the St. Gabriel Research Station in Iberville Parish. Tests I (‘Pioneer 9692’) and II (‘Hartz 7190’) were both conducted on 8 Sep when soybeans were in the R5 growth stage. Treatments were applied using a tractor-mounted, CO2 pressurized sprayer calibrated to deliver 15 gpa at 40 psi through 8002 flat fan nozzles. Plots in both tests were 5 rows wide (36 inch row spacing) by 50 ft, arranged in a RCB design, with four blocks. At 3 and 7 DAT in each test, one 25 sweep sample was taken from each plot with a standard 15 inch diam sweep net. Both nymph and adult SGSB were counted. No rainfall occurred during either test.

Evaluation of Dimilin and Benlate for Soybean Insect Pest and Disease Control, 1991

Abstract The experiment was conducted at the Texas A&M University Agricultural Research and Extension Center, Beaumont. The experimental design was a randomized complete block with 6 treatments and 4 replications. Soil type was a Midland silty clay loam. Plot size was 40 ft × 6 rows (32-inch row spacing). Plots were planted 4 Jun at about 10 seeds/ft. Immediately after planting, plots were treated with 2 pt Dual + 1 qt Roundup + % pt Scepter per acre. Soybeans emerged 10 Jun. On 16 Aug (when plants were R2—3 and insect pest populations were beginning to increase) treatments were applied to 4 rows of a plot using a Solo backpack sprayer. Finished spray volume was 20 gal/acre. Immediately before application and 5, 12, 21, 28, 35, and 42 d after this initial application, plots were sampled for insects. Each sample consisted of shaking soybean plants along 9 ft of row over a vertical beat sheet. Insects were shaken and brushed from the vertical beat sheet into a plastic bag which was frozen for later inspection of the contents. One sample (9 ft of sampled row) was taken in each plot on each sample date. On 9 Sep (when soybeans were R5) a second application of Benlate was made to all treatments with Benlate (thus, after all treatments were applied, treated plots were exposed to a single application of Dimilin and/or a double application of Benlate). On the same dates plots were sampled for insects, 15 leaflets (5 each from top, middle, and bottom third of canopy) were randomly removed from each plot and taken to a laboratory where estimates of % defoliation were recorded by comparing leaflets with templates of leaflets of known defoliation. From time of initial application to the last sample date 5.26 inches of rain was recorded. On 21 and 29 Oct plots were visually rated for cercospora leaf blight and anthracnose disease severity, respectively. At maturity 120 ft of row in each plot were harvested with a small plot combine. Yields were adjusted to 13% moisture. Insect count data were transformed using Vx + 0.5 and all data analyzed by ANOVA and means separated by DMRT.

Evaluation of Dimilin and Benlate for Soybean Insect Pest and Disease Control, 1992

Abstract The experiment was conducted at the Texas A&M University Agricultural Research and Extension Center, Beaumont. The experimental design was a randomized complete block with 6 treatments and 4 replications. Soil type was a Midland silty clay loam. Plot size was 40 ft × 6 rows (32-inch row spacing) with 2 buffer rows on either side of each plot. Plots were planted 22 May at about 10 seeds/ft and treated with 2 pt Dual and % pt Scepter/acre in a finished spray volume of 20 gal/acre. Seedlings emerged 26 May. Treatments were applied by a Solo backpack sprayer to the middle 4 rows of each treated plot when soybeans were R 2/3 (6 Aug) and R 5 (28 Aug). Final spray volume was 20 gal/acre. An application of Benlate 50W at R5 was mistakenly added to the treatment with 2 applications of Dimilin at the high rate. One day before and 4, 22, 35, 41, 48, 55, 62, and 69 d after the initial application (6 Aug), 9 ft of row in each plot were sampled for arthropods using a vertical beat sheet. Samples were taken to the lab, frozen, and contents identified at a later date. On 4 Nov plots were visually rated for anthracnose which was the predominant disease. At maturity (19 Nov), 40 ft of row in each plot was harvested with a small plot combine. Yields were adjusted to 13% moisture. Insect count data were transformed using Vx + 0.05 and all data analyzed by ANOVA and DMRT where appropriate.

Evaluation of Karate for Soybean Insect Pest Control, 1991

Abstract The experiment was conducted at the Texas A&M University Agricultural Research and Extension Center, Beaumont. The experimental design was a randomized complete block with 3 treatments and 4 replications. Soil type was a Midland silty clay loam. Plot size was 40 ft × 6 rows (32-inch row spacing). Plots were planted 4 Jun at about 10 seeds/ ft. Immediately after planting, plots were treated with 2 pt Dual + 1 qt Roundup + % pt Scepter per acre. Soybeans emerged 10 Jun. On 9 Sep (when plants were R5 and insect pest populations were peaking) treatments were applied using a 4 nozzle (800067 tips) hand-held boom sprayer. Finished spray volume was 13.1 gal/acre. Five days before and 2, 9, 17, 23, and 32 d after application, plots were sampled for insects. Each sample consisted of shaking soybean plants along 6 ft of row over a vertical beat sheet. Insects were shaken and brushed from the vertical beat sheet into a plastic bag which was frozen for later inspection of the contents. One sample (6 ft of sampled row) was taken in each plot on each sample date. From 12 Sep to 5 Oct 0.87 inches of rain fell. At maturity 120 ft of each plot was harvested with a small plot combine and yields adjusted to 13% moisture. Insect data were transformed using VX + 0.5 and all data analyzed by ANOVA and where appropriate means separated by DMRT.

Control of Soybean Insect Pests in the Macon Ridge Region of Louisiana, 1993

Abstract Two tests were conducted to evaluate insecticide efficacy against foliage feeding insect pests of soybean. Plots consisted of 5 rows (40 inch centers) × 50 ft, were planted on 7 Jun. Treatments in both tests were arranged in a RCBD with 4 replications. Insecticides were applied with a tractor-mounted boom and compressed air system calibrated to deliver 10 gal total spray/acre through Teejet X-12 hollow cone nozzles (2/row) at 30 psi. Treatments were applied on 18 Aug and 20 Aug in Test 1 and Test 2, respectively. Insecticide efficacy was evaluated at 2 and 7 DAT using two 25-sweep samples/plot with a standard 15 inch diam sweep net. Rows 2 and 3 were sampled 2 DAT and rows 4 and 5 were sampled 7 DAT. On 20 Aug. 0.5 inches rainfall was recorded over the test area. However, the treatments in Test 2 were not applied until after the rainfall had occurred.