Pest Of Soybean Research Articles

Developing a Residual Testing Protocol for Soybean Aphid (Hemiptera: Aphididae)

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), continues to be an economically important insect pest of soybean in the northcentral region of the United States since its first report in 2000. Control has traditionally relied on foliar applications of pyrethroid and organophosphate insecticides; however, recent confirmed failures of pyrethroids in the region have prompted immediate management concerns. Insecticidal modes of action are limited, and there is a need for assessing residual efficacy of exisiting and new insecticides for soybean aphid. We developed a field-based protocol to evaluate the residual efficacy of treated foliage, and tested our method with two insecticides. Our residual testing protocol can be utilized for residual efficacy evaluations of other pests and in other systems.

Effectiveness of Trichogramma pretiosum in controlling lepidopterous pests of soybean crops

Controlling lepidopteran pests in soybean in Uruguay usually involves the application of chemical insecticides with risks to health and the environment. As part of an inundative biological control program using Trichogramma pretiosum, a plot trial at three sites located in the department of Soriano (Uruguay), in the 2019-2020 growing season, compared this conventional practice with different doses of the egg parasitoid, number of release capsules per hectare, different number of releases in the culture cycle and ground and aerial releases (with or without release capsules). Using the cloth method, the number of larvae per linear meter and the defoliation percentage were evaluated over 6 weekly samplings. Although the best results were obtained with the application of chemical insecticides, two releases of T. pretiosum by terrestrial methods, 20 days apart, or 4 weekly applications by means of a drone, reached the best results below the thresholds of sanitary intervention, both options with 200,000 parasitoids per hectare. This biological tool can differentiate and value Uruguayan agricultural production.

Molecular Basis Underlying Common Cutworm Resistance of the Primitive Soybean Landrace Peking

The common cutworm (CCW; Spodoptera litura) is one of the major insect pests of soybean in Asia and Oceania. Although quantitative trail loci related to CCW resistance have been introduced into leading soybean cultivars, these do not exhibit sufficient resistance against CCW. Thus, understanding the genetic and metabolic resistance mechanisms of CCW as well as integrating other new resistance genes are required. In this study, we focused on a primitive soybean landrace, Peking, which has retained resistances to various pests. We found a resistance to CCW in Peking by the detached-leaf feeding assay, and subsequently determined the genetic and metabolic basis of the resistance mechanism using chromosome segment substitution lines (CSSLs) of Peking. Several characteristic metabolites for Peking were identified by the metabolomic approach using liquid chromatography/mass spectrometry combined with a principle component analysis. The structure of seven metabolites were determined by nuclear magnetic resonance (NMR) analysis. The genomic segments of Peking on chromosome 06 (Chr06) and Chr20 had a clear association with these metabolites. Moreover, a line possessing a Peking genomic segment on Chr20 inhibited growth of the CCW. The genetic factors and the metabolites on Chr20 in Peking will be useful for understanding mechanisms underlying CCW resistance and breeding resistant soybean cultivars.

Effect of several types of insecticide on predator population and damage intensity due to soybean pest attack in South Sulawesi, Indonesia

Spodoptera litura was one of the pests that caused soybean seed yield decrease in South Sulawesi. In order to challenge the pests, farmers still largely choose chemical insecticides. This research aimed to establish effectiveness level of several insecticide types that were frequently used by farmers. The design used was Randomized Block Design with 7 treatments (6 insecticide types and 1 control) with 3 replications. The insecticide types examined were: 1) acephate 75%, 2) thiamethoxam 200 g/L + chlorantraniliprole 100 g/L, 3) permethrin 200 g/L, 4) chlorpyrifos 550 g/L + cypermethrin 60 g/L, 5) deltamethrin 50 g/L, 6) profenofos 500 g/L, and 7) polyculture, soybean + corn (control). The result showed that insecticide type of thiamethoxam 200 g/L + chlorantraniliprole 100 g/L was the most effective insecticide to control S. litura with soybean leaves damage intensity (15.19%) and population of Bemisia tabaci whitefly (5.07 tails plant-1). However, thiamethoxam 200 g/L + chlorantraniliprole 100 g/L mostly killed Lycosa sp. predator (0.63 tails plant-1) and Crocothemis servillia (3.26 tails plant-1). The highest predator population was found in multiple cropping of soybean and corn, C. servillia (3.94 tails plant-1), and Lycosa sp. (3.26 tails plant-1). The insecticide of chlorpyrifos 550 g/L + cypermethrin 60 g/L were effective to control soybean pod borer pest Etiella zinckenella (2.40%). Furthermore, insecticide of deltamethrin 50 g/L was effective to control Aphis glycines pest (2.05 tails plant-1). Several types of insecticides are effective in controlling S. litura, N. viridula, and B. tabasi pests, but these insecticides are also effective in killing predators. The highest predator population is soybean-corn intercropping. Keywords: Soybean, insecticides, pests, intensity of damage, predators, seed yields.

Detection and classification of soybean pests using deep learning with UAV images

This paper presents the results of the evaluation of five deep learning architectures for the classification of soybean pest images. The performance of Inception-v3, Resnet-50, VGG-16, VGG-19 and Xception was evaluated for different fine-tuning and transfer learning strategies over a dataset of 5,000 images captured in real field conditions. The experimental results showed that the deep learning architectures trained with a fine-tuning can lead to higher classification rates in comparison to other approaches, reaching accuracies of up to 93.82%. In addition, deep learning architectures outperformed traditional feature extraction methods, such as SIFT and SURF with Bag-of-Visual Words approach, the semi-supervised learning method OPFSEMImst, and supervised learning methods used to classify images, for example, SVM, k-NN and Random Forest. The results indicate that architectures evaluated can support specialists and farmers in the pest control management in soybean fields.

Performance of Genetically Modified Soybean Expressing the Cry1A.105, Cry2Ab2, and Cry1Ac Proteins Against Key Lepidopteran Pests in Brazil.

The pyramided genetically modified (GM) soybean [Glycine max L. (Merr.)] MON87751 × MON87708 × MON87701 × MON89788, expressing Cry1A.105, Cry2Ab2, and Cry1Ac from Bacillus thuringiensis Berliner, was approved for commercial use in Brazil. We conducted laboratory, greenhouse, and field studies to assess the efficacy of this Bt soybean against key soybean lepidopteran pests. Neonates of Anticarsia gemmatalis (Hübner) (Lepidoptera: Erebidae), Chrysodeixis includens (Walker), and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) were exposed to Bt proteins in diet-overlay bioassays. MON87751 × MON87708 × MON87701 × MON89788 soybean and individual components were evaluated in laboratory (leaf disc), greenhouse (high artificial infestations), and in field conditions (natural infestations). Neonates of A. gemmatalis, C. includens, and H. armigera were highly susceptible to Cry1A.105 (LC50 from 0.79 to 48.22 ng/cm2), Cry2Ab2 (LC50 from 1.24 to 8.36 ng/cm2), and Cry1Ac (LC50 from 0.15 to 5.07 ng/cm2) in diet-overlay bioassays. In laboratory leaf disc bioassays and greenhouse trials, MON87751 × MON87708 × MON87701 × MON89788 soybean as well as the individual components were highly effective in controlling A. gemmatalis, C. includens, and H. armigera. Similarly, under field conditions, the pyramided genotypes expressing Cry1A.105, Cry2Ab2, and Cry1Ac were highly effective at protecting soybean against C. includens. We concluded that the individual Bt proteins expressed by GM soybean MON87751 × MON87708 × MON87701 × MON89788 killed all or nearly all the susceptible A. gemmatalis, C. includens, and H. armigera, fulfilling one important criterion for successfully delaying resistance to pyramided Bt crops.

Biology and predatory ability of the reduviid Sycanus falleni Stal (Heteroptera: Reduviidae: Harpactorinae) fed on four different preys in laboratory conditions

• Biology of reduviid Sycanus falleni were determined and comparative. • Predatory ability and body weight of S. falleni were determined and comparative. • The number of four preys were killed by reduviid S. falleni were different. • The body weight I, V nymphal instars and adults weren't different. The reduviid Sycanus falleni Stal (Heteroptera: Reduviidae) is an important predatory insect in biological control pests in vegetable, soybean, corn and rice plants. It is omnivorous species and has a wide range of prey. The influence of fed on four different preys as Pieris rapae (Linnaeus), Spodoptera litura (Fabricius), Plutela xylostella (Linnaeus) and Corcyra cephalonica (Stainton) on biological parameters, ability to eat prey and body weight of the nymph and adult of S. falleni were evaluated in laboratory conditions (26 ± 2 °C, 75 ± 5% RH and light:dark 14:10 h) in Vietnam. The biological parameters of reduviid S. falleni reared on the laboratory were determined by observing the development stage of egg, development stage of nymph, pre-oviposition period, life cycle, longevity of adult, number of eggs laid, sex ratio. The nymph and adults of reduviid S. falleni consumption the number of P. xylostella, P. rapae , S. litura and C. cephalonica larvae were different, and an adult female consumed more than an adult male while the body weight of the I and V nymphal instars, male and female adults of reduviid S. falleni wasn't significantly different (P < 0.01).

Identification of novel haplotype of a cyst nematode resistance gene, GmSNAP18 in soybean [Glycine max (L.) Merr.

Soybean cyst nematode (SCN) is one of the most damaging pest of soybean. Discovery and characterization of the genes involved in SCN resistance are important in soybean breeding. Soluble NSF attachment protein (SNAP) genes are related to SCN resistance in soybean. SNAP genes include five gene families, and 2 haplotypes of exons 6 and 9 of SNAP18 are considered resistant to the SCN. In present study the haplotypes of GmSNAP18 were surveyed and chacterized in a total of 60 diverse soybean genotypes including Korean cultivars, landraces, and wild-types. The target region of exons 6 and 9 in GmSNAP18 region was amplified and sequenced to examine nucleotide variation. Characterization of 5 haplotypes identified in present study for the GmSNAP18 gene revealed two haplotypes as resistant, 1 as susceptible and two as novel. A total of twelve genotypes showed resistant haplotypes, and 45 cultivars were found susceptible. Interestingly, the two novel haplotypes were present in 3 soybean lines. The information provided here about the haplotypic variation of GmSNAP18 gene can be further explored for soybean breeding to develop resistant varieties.

Resistance among selected wild soybean and associated soybean accessions against two virulent colonies of Aphis glycines (Hemiptera: Aphididae)

The soybean aphid (Aphis glycines) is an important pest of soybean (Glycine max). Wild soybean (Glycine soja; also known as ‘soja’) has many useful traits, including some accessions with aphid resistance that may be incorporated into modern soybean cultivars. The objective of this work was to evaluate 76 selected soja accessions and 14 associated soybean accessions for resistance against two virulent colonies of soybean aphid in environmental-chamber experiments. In free-choice tests, soja accessions PI 407175, PI 407190, PI 407206, PI 407240, PI 507624 and PI 562558 were resistant against the Accrue colony, and PI 407191wf and PI 597458 C were resistant against the Volga16 colony. None of the soybean test accessions except the resistant check, PI 437696, showed resistance against either colony in free-choice tests. In no-choice tests, soja accession PI 507624 showed strong resistance against the Accrue colony; whereas PI 407240 and PI 407190 had intermediate aphid levels; PI 597458 C showed strong resistance to Volga16 aphids, and PI 407191wf had an intermediate level of resistance. Based on results from both sets of tests, soja accessions PI 507624 and PI 597458 C may be strong candidates in breeding programs to develop aphid-resistant soybean cultivars.

Forest cover and proximity decrease herbivory and increase crop yield via enhanced natural enemies in soybean fields

Abstract Non‐crop habitats are essential for sustaining biodiversity of beneficial arthropods in agricultural landscapes, which can increase ecosystem services provision and crop yield. However, their effects on specific crop systems are less clear, such as soybean in South America, where the responses of pests and natural enemies to landscape structure have only recently been studied. Here, we analysed how native forest fragments at local and landscape scales influenced arthropod communities, herbivory and yield in soybean fields in central Argentina. To do this, we selected soybean fields located in agricultural landscapes with varying proportions of forest cover. At two distances (10 and 100 m) from a focal forest fragment, we sampled natural enemy and herbivore arthropods, and measured soybean herbivory and yield. We focused on herbivore diversity, abundance of key soybean pests in the region (caterpillars and stink bugs), and their generalist and specialist natural enemies. Higher abundance of predators, lower herbivory rates and increased yield were found near forests, while overall forest cover in the landscape was positively related with parasitoid and stink bug abundance, soybean yield, and negatively with herbivory. Moreover, yield was positively linked to richness and abundance of generalist and specialist enemies and independent of herbivory according to piecewise Structural Equation Models. Synthesis and applications. Our results show positive effects of native forests on biodiversity and yield in soybean crops, highlighting the need for conservation of forest fragments in agricultural landscapes. Moreover, the relation between natural enemies and crop yield suggests that Chaco forests support a diverse and abundant community of natural enemies that can provide sustained levels of ecosystem services and result in positive effects for farmers.

Transcriptomic and proteomic analyses of the mechanisms of overwintering diapause in soybean pod borer (Leguminivora glycinivorella).

Soybean pod borer (Leguminivora glycinivorella) is an important soybean pest in north-eastern Asia, whose mature larvae overwinter in a diapause state. Disruption of winter diapause may be a valuable tool in pest management. However, the molecular mechanisms regulating diapause in this species have not yet been elucidated. We compared the transcriptomes and proteomes between diapause and mature larvae and between mature and newly developed pupae to identify the genes and proteins associated with diapause. Thirty-seven differentially expressed genes and their proteins changed synchronously between diapause and mature larvae and 82 changed synchronously between diapause larvae and newly developed pupae. Among these, genes involved in fatty acid biosynthesis and the longevity regulating pathway were up-regulated in diapause larvae and down-regulated in newly developed pupae, suggesting that they may regulate diapause. One fatty acid synthase (FAS) gene and two small heat shock genes (HSP19.8 and HSP18.9) were chosen for further functional analysis. After RNA interference (RNAi)-mediated knockdown of FAS, the survival of mature larvae was significantly lower than that of control larvae, but the mean developmental time from first-instar larva to adult remained unchanged. RNAi-mediated knockdown of HSP19.8 and HSP18.9 severely shortened the mean developmental time, causing approximately 50% larvae to develop directly into pupae. FAS and the small heat shock gene play roles in diapause regulation and larvae survival. This study provides important information that may assist in understanding the molecular regulatory mechanisms of overwintering diapause of this important agricultural insect pest. © 2020 Society of Chemical Industry.

The Resistant Soybean-Aphis glycines Interaction: Current Knowledge and Prospects

Soybean aphids (Aphis glycines Matsumura) are invasive insect pests of soybean, and they cause significant yield losses. Resistance to soybean aphids is conferred by Resistance to Aphis glycines (Rag) genes. Since the first discovery of aphid-resistant soybean genotypes in 2004, several studies have attempted to characterize Rag genes from aphid-resistant soybean genotypes. To date, 12 Rag genes and four quantitative trait loci for aphid resistance have been reported on soybean chromosomes 07, 08, 13, 16, and 17. Although candidate genes have been proposed for several discovered Rag loci, additional studies are needed to pinpoint, validate, and further explain the potential mechanisms of Rag gene action. A major challenge to utilizing host plant resistance is the discovery of virulent aphid biotypes that can colonize aphid-resistant soybean. This occurrence suggests the need for additional studies to devise strategies to enhance the effectiveness of aphid-resistant soybean. In this mini review, we discuss current knowledge on the resistant soybean-Aphis glycines interaction, potential mechanisms of Rag gene action, opportunities to discover new Rag genes, and prospects for utilization of host plant resistance to manage soybean aphids. A clearer understanding of host plant resistance to soybean aphids will guide researchers on strategies for developing soybean varieties with more durable aphid resistance, reducing the present challenge of virulent aphid biotypes.

Challenges for Adoption of Integrated Pest Management (IPM): the Soybean Example.

Soybean is considered one of today's most important crops. Planted on millions of hectares worldwide, the management of soybean pests usually requires large amounts of chemicals. However, a key component to meet the increasing demand for food due to the rapidly growing global population is protecting crops from pests while maintaining environmental quality through ecologically and economically sound integrated pest management (IPM) practices. Not only can IPM result in more profitable agriculture due to the reduction of pest control costs but also assures equitable, secure, sufficient, and stable flows of both food and ecosystem services. Despite those ecological and economic benefits, the vast areas of cultivated soybean as well as the convenience of spraying insecticides are encouraging the adoption of prophylactic pest control as a relatively inexpensive safeguard compared to IPM practices. Thus, in this forum, we discuss the reasons for soybean IPM not reaching its potential. We give examples of how we can revive this once successful pest management program with a focus on experiences in Brazil and the USA. We analyze IPM case studies to illustrate the need for growers to have easy and fast access to IPM information on its medium- and long-term benefits. Overall, this forum highlights the importance of IPM for agricultural sustainability including ecological and financial benefits.

Development of web-based system for soybean insect pests management

The paper describes the development of a web-based system for identification of soybean insects and their management. It presents the system design, development methodology, functionality and utility of the system. The user interface of the system is developed using ASP.NET and backend using SQL. It is designed using responsive web design so that the users can easily use the system on different devices with variable screen sizes-Desktops, Laptops, iPads, Tablets and Mobile phones. The system is accessible from the institute website https://iisrindore.icar.gov.in. It is very useful for farmers in taking right decision at right time in their fields. The users could identify the insects correctly with the image-based identification interface. The information in Hindi language will help farmers to easily understand the contents. The systemwas evaluated on eight user interface design features on 1-10 point scale. The overall average rating was more than 8 points indicating that most ofthe evaluators were satisfied with the user interface. It served as an effective IT tool for farmers to take appropriate and timely measures to minimize field losses due to insect attack.

Susceptibility of Euschistus heros and Dichelops furcatus (Hemiptera: Pentatomidae) to insecticides determined from topical bioassays and diagnostic doses for resistance monitoring of E. heros in Brazil

The Neotropical brown stink bug, Euschistus heros (F.), and the green belly stink bug, Dichelops furcatus (F.) (Hemiptera: Pentatomidae), are the main sucking pests of soybean and maize in Brazil. Here, we characterized the susceptibility of populations of E. heros and D. furcatus to insecticides and define doses for resistance monitoring of E. heros. Stink bug populations collected in the seasons from 2018 to 2020 were exposed to technical grade insecticides in topical bioassays. Populations of E. heros presented low variation in the susceptibility to acephate (LD50 = 0.22–0.69 μg a.i./stink bug), thiamethoxam (LD50 = 0.0039–0.032 μg a.i./stink bug) and bifenthrin (LD50 = 0.021–0.10 μg a.i./stink bug), with resistance ratios < 8.2-fold in relation to a susceptible population. However, the same populations showed high variation in the susceptibility to lambda-cyhalothrin (LD50 = 0.023–0.35 μg a.i./stink bug) with resistance ratios from 3.1- to 15.7-fold. Populations of D. furcatus had a similar susceptibility to acephate (LD50 = 0.30–0.53 μg a.i./stink bug), thiamethoxam (LD50 = 0.070–0.14 μg a.i./stink bug) and lambda-cyhalothrin (LD50 = 0.27–0.56 μg a.i./stink bug), with resistance ratios < 2.1-fold. The diagnostic doses of 1.30 (acephate), 0.34 (thiamethoxam), 0.36 (bifenthrin) and 1.73 (lambda-cyhalothrin) μg a.i./stink bug were defined for monitoring the susceptibility of E. heros. In these doses, mortalities of E. heros populations ranged from 55.3% to 100%. Our findings indicate that E. heros presents a lower inter-population variation in susceptibility to acephate, bifenthrin and thiamethoxam than lambda-cyhalothrin, while D. furcatus had similar susceptibility to the insecticides tested. The diagnostic doses defined here will be used in further resistance monitoring programs.

EFIKASI EKSTRAK BIJI JARAK PAGAR MORTALITAS LARVA PENGGULUNG DAUN (Lamposema indicate) PADA TANAMAN KEDELAI (Glycine max)

Soybean leaf roller known as Lamposema indicata. These insects attack the leaves of soybean plants by rolling up soybean leaves, that are launched 3-4 weeks after planting. The research aims to find out application of Jathropha curcas extract againts the mortality of soybean leaf roller pest (Lamposema indicata) and reduce damage to soybean plants. This research was conducted in the experimental garden, Faculty of Agriculture, Teuku Umar University in October to November 2019. The research was arranged in a non factorial Completely Randomized Design consisting of 4 levels with 5 replications. The factors experience is Jathropha curcas seed extract concentrate are E1 (control), E1 (20%, E2 (13.3% and E3 (10%). The results shows Lamprosema mortality shows the highest found in the E3 regulation, this is because in the E3 setting it has a high concentration so that the composition of the poisons contained is also high. Castor seed extract (Jatropha curcas) contains the composition of phorbol ester and cursin. Based on the observations displayed during the observation, namely changes in behavior, slowing movement of larvae, discoloration from clear green to pale yellow and compacting of the larva's body cavity.Keywords: Effectiveness of concentration, mortality, leafworm caterpillars

Susceptibility of First Instar Hippodamia convergens (Coleoptera: Coccinellidae) and Chrysoperla rufilabris (Neuroptera: Chrysopidae) to the Insecticide Sulfoxaflor

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), continues to be the most economically important arthropod pest of soybean in the Midwest. Currently, management tactics for A. glycines rely on scouting and application of broad-spectrum insecticides. However, broad-spectrum insecticides are toxic to most natural enemies of this aphid. Selective insecticides may provide an alternative strategy for suppressing A. glycines populations while conserving populations of its natural enemies. Therefore, the aim of this study was to evaluate the potential lethal and sublethal effects of sulfoxaflor (a relatively new selective insecticide), to 2 of this pest's natural enemies, Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae). Laboratory bioassays were performed on first instars of both predators with residual toxicity evaluated over time until adult emergence. Parameters evaluated were mortality and developmental time for larvae and pupae, and adult body size. Fecundity also was determined for C. rufilabris. We found that sulfoxaflor was not toxic to first instar C. rufilabris. However, developmental time to adult was significantly delayed after exposure to this insecticide, but fecundity and body size were not negatively affected. For H. convergens, sulfoxaflor at 25% of the field rate was toxic to first instars. No significant differences were found with regard to developmental time and body size. It is important to note that sulfoxaflor, though relatively less toxic than some insecticides, is not entirely without consequence if natural enemies are exposed. The present study emphasizes the importance of examining earlier life stages and potential sublethal effects when evaluating the toxicity of insecticides in the presence of natural enemies.

Dispersal of the Common Cutworm, Spodoptera litura, Monitored by Searchlight Trap and Relationship with Occurrence of Soybean Leaf Damage.

The common cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is a major pest of soybean. Pheromone traps are used to monitor male adults, but the catch peaks do not always predict leaf damage in soybean fields. Thus, there is no accurate means of forecasting soybean damage, and insecticide is applied on the basis of farmers’ observations of actual damage in fields. To understand the occurrence of soybean leaf damage, the dispersal of S. litura in a soybean field in southwestern Japan was preliminarily investigated using a searchlight trap in comparison to a pheromone trap at one location, from August to mid-October in 2016–2018. To determine the relationship between pest arrival and crop damage, trap catch numbers and the number of soybean leaves damaged by 1st-instar larvae were examined by separately comparing raw numbers and cumulative numbers. The raw catch numbers of the two trap types in August and September 2016 and 2018 preceded subsequent damage peaks by an average of 5.3 days. This temporal difference coincided with the estimated duration of the egg stage plus an assumed mating period. Furthermore, the cumulative catch numbers of the two traps in August and September were linearly associated with cumulative damaged leaves in the same period in each year and in the three-year period. The coefficient of determination (R2) of linear regression between the cumulative catch numbers of the searchlight trap and the cumulative damaged leaves for the three-year period was much higher than that between the cumulative catch of the pheromone trap and cumulative damage. This suggests that soybean leaf damage is closely linked to the number of S. litura arrivals at the survey site. Thus, the searchlight trap captured S. litura arrivals better than the pheromone trap. As the linear regression function of the cumulative catch of the searchlight trap for the three-year period was tentatively correlated with a prefectural economic injury level for soybean fields, it might be feasible to predict S. litura-induced soybean damage using searchlight traps. The cumulative female catch number of the searchlight trap was also linearly associated with damaged leaves, but the coefficient of determination was generally lower than that with the cumulative total catch. The female ratio of searchlight trap catches in September was <0.5 in contrast to S. litura migrating overseas (>0.5). The advantages and disadvantages of the two trapping methods, as well as necessary further studies are discussed. Our findings provide a foundation for S. litura monitoring with searchlight traps.

Mechanisms of Soybean Host-Plant Resistance Against Megacopta cribraria (Hemiptera: Plataspidae)

A number of soybean varieties traditionally bred for resistance to various soybean arthropod pests have been identified as resistant to Megacopta cribraria (F.) (Hemiptera: Plataspidae). However, the mechanisms of host-plant resistance (HPR) in this system are not understood. The goal of this study was to identify the mechanisms of resistance by examining the role of plant volatile organic compounds (VOCs) and free amino acids (FAAs) among 16 soybean varieties. Choice and no-choice cage experiments identified several soybean varieties that demonstrated antixenosis as well as antibiosis. However, resistance varied over time in certain soybean varieties, such as N02-7002 and PI567352B. Mean nymph number from choice experiments had positive correlations with the FAAs asparagine, tryptophan, alanine, phenylanaline, and serine; negative correlation with leucine and threonine. Four plant volatiles, hexanal, 2-pentylfuran, beta-cyclocitral, and cis-9-hexadecenal, were positively correlated with subsequent nymph development, whereas n-hexadecenoic acid was negatively correlated with nymph number only, in adult choice cage experiments. This study contributes to understanding the mechanisms of HPR through associations with plant VOCs and FAAs in relation to M. cribraria development and provides useful knowledge for developing soybean varieties for M. cribraria management.

Release of the egg parasitoid Telenomus podisi to manage the Neotropical Brown Stink Bug, Euschistus heros, in soybean production

Eushistus heros is one of the major pests in soybean in South America. Not only has insecticides constantly failed on its control but also triggered different negative side effects related to the overuse of chemicals. Among the biocontrol agents that can be used in Augmentative Biological Control, Telenomus podisi stands out due to its high parasitism capacity on eggs of its hosts. Therefore, this study aimed to assess T. podisi release strategies and moments (release done together with the detection of first E. heros adults in the area as well as together with fungicide sprays), in order to reach optimal parasitoid field performance. For this purpose, a replicated experiment was conducted with a soybean crop located in Londrina, Paraná, Brazil, during 2017/18 and 2018/19 crop seasons. Treatments consisted of 18750 released T. podisi pupae (released either inside cardboard capsules or as unprotected pupae sprinkled in bulk, at different moments) and were evaluated against insecticide spraying strategies. At harvest, yield and quality of the seeds were measured. Overall, our results clearly indicate that T. podisi pupae can be released either encapsulated or unprotected, with similar efficacy. Their release in the field increased E. heros egg parasitism to 70% and 50%, in 2017/2018 and 2018/2019, respectively. Thus, T. podisi can be efficiently used to control stink bug eggs. However, since the number of stink bugs ≥0.5 cm in the field highly depends on its migration from neighboring fields, it is important to use T. podisi inside integrated pest management.