Pest Of Soybean Research Articles

Characterizing the differential susceptibility and resistance to insecticides in populations of Chrysodeixis includens and Rachiplusia nu (Lepidoptera: Noctuidae) in Brazil.

Chrysodeixis includens (Walker) and Rachiplusia nu (Guenée) are major Plusiinae pests of soybean in the Southern Cone region of South America. In recent decades, C. includens was the main defoliator of soybean in Brazil, but from 2021 onwards, R. nu emerged as an important soybean pest in various regions of the country. Here, we characterize the differential susceptibility and resistance to insecticides in these Plusiinae pests from two soybean regions of Brazil. Except for spinetoram and chlorfenapyr (comparable lethality against both species) and a Bt-based biopesticide (more lethal for C. includens), the tested insecticides showed higher lethality against R. nu than against C. includens, but populations of the same species, even separated by long distances, presented similar resistance levels. For both species, the 90% lethal concentration (LC90) values of most insecticides were higher than the field-recommended dose. Nevertheless, the field-recommended doses of spinetoram, metaflumizone, emamectin benzoate, cyclaniliprole and chlorfenapyr showed comparable control efficacy against both species, whereas indoxacarb, chlorantraniliprole, flubendiamide, teflubenzuron and chlorfluazuron were more lethal for R. nu, and methoxyfenozide and the Bt-based insecticide were more lethal for C. includens. Thiodicarb, methomyl and lambda-cyhalothrin showed low lethality against both species. Large interspecific differences in the susceptibility to insecticides was found in major Plusiinae pests of soybean in Brazil. Furthermore, variations in susceptibility to insecticides occurred consistently among species and populations, regardless of the collection site and thus despite unequal temporal and spatial exposure to insecticides. These results demonstrate that accurate species identification is essential for effective control of Plusiinae in soybean. © 2024 Society of Chemical Industry.

Vertical distribution and tissue selection of Helicoverpa zea (Lepidoptera: Noctuidae) adult oviposition and neonates on soybean with an indeterminate or determinate growth habit.

Helicoverpa zea (Boddie) is a polyphagous pest that can cause serious damage to crops, including soybeans (Glycine max L.). In soybeans with both determinate and indeterminate growth habits, H. zea larvae are more commonly found on leaves compared to blooms, stems, and pods. Past research demonstrated that H. zea adults tend to oviposit near the upper part of the plant canopy in soybeans with a determinate growth habit. However, ovipositional selection on soybeans with an indeterminate growth habit is unknown. We hypothesized that H. zea would oviposit more uniformly throughout the canopy on indeterminate soybean growth habits due to more diffuse reproductive tissue. We planted field and greenhouse experiments with varieties sharing a similar relative maturity (2 maturity group [MG] 5.2 varieties and 2 MG 5.4/5.5 varieties) but with different growth habits. To test oviposition selection, adult H. zea females were allowed to oviposit under field and caged conditions. We counted the number of H. zea eggs and neonates on each plant tissue type from each of 3 equal parts in the plant canopy: upper, middle, and lower. In both experiments, eggs and neonates were most common on leaves at the top of the plant regardless of soybean growth habit. Consequently, ovipositional selection is likely independent of reproductive tissue availability, and patterns of oviposition through the canopy are similar in growth habits. An improved understanding of H. zea ecology in soybeans relative to indeterminate growth habits may improve recommendations for managing this significant pest of soybean.

GmSABP2-1 encodes methyl salicylate esterase and functions in soybean defense against soybean cyst nematode.

The soybean gene GmSABP2-1 encodes methyl salicylate esterase and its overexpression led to significant reduction in development of pathogenic soybean cyst nematode. Soybean cyst nematode (SCN, Heterodera glycines) is one of the most devastating pests of soybean (Glycine max L. Merr.). In searching for SCN-defense genes, a soybean gene of the methylesterase (MES) family was found to be upregulated in an SCN-resistant soybean line and downregulated in an SCN-susceptible line upon SCN infection. This gene was designated as GmSABP2-1. Here, we report on biochemical and overexpression studies of GmSABP2-1 to examine its possible function in SCN resistance. The protein encoded by GmSABP2-1 is closely related to known methyl salicylate esterases. To determine the biochemical function of GmSABP2-1, a full-length cDNA of GmSABP2-1 was cloned into a protein expression vector and expressed in Escherichia coli. The resulting recombinant GmSABP2-1 was demonstrated to catalyze the demethylation of methyl salicylate. The biochemical properties of GmSABP2-1 were determined. Its apparent Km value was 46.2 ± 2.2μM for methyl salicylate, comparable to those of the known methyl salicylate esterases. To explore the biological significance of GmSABP2-1 in soybean defense against SCN, we first overexpressed GmSABP2-1 in transgenic hairy roots of an SCN-susceptible soybean line. When infected with SCN, GmSABP2-1-overexpressing hairy roots showed 84.5% reduction in the development of SCN beyond J2 stage. To provide further genetic evidence for the role of GmSABP2-1 in SCN resistance, stable transgenic soybean plants overexpressing GmSABP2-1 were produced. Analysis of the GmSABP2-1-overexpressing lines showed a significant reduction in SCN development compared to non-transgenic plants. In conclusion, we demonstrated that GmSABP2-1 encodes methyl salicylate esterase and functions as a resistance-related gene against SCN.

Evaluation of Bio-efficacy of Compatible Agrochemicals against Sucking Pests in Soybean

A study was conducted at Agricultural Research Station (UAS, Dharwad), Sankeshwar, Karnataka during Kharif 2022-23 to assess the effectiveness of various agrochemicals alone and in combinations against whiteflies and thrips in soybean. Fifteen treatments were tested with three replications each. Among the treatments, diafenthiuron 50 WP at a concentration of 1.25 g/l exhibited the lowest mean population of whiteflies and thrips, with 2.63 and 3.22 per three leaves, respectively. This performance was comparable with its combination treatments, includes diafenthiuron 50 WP @ 1.25 g/l combined with propiconazole 25 EC @ 1 ml/l and 19:19:19 @ 5 g/l (2.92 whiteflies and 3.50 thrips/3 leaves), as well as diafenthiuron 50 WP @ 1.25 g/l combined with tebuconazole 50 + trifloxystrobin 25 WG @ 0.5 g/l and 19:19:19 @ 5 g/l (3.19 whiteflies and 3.74 thrips/3 leaves). Combination treatments effectively reduced whiteflies and thrips population as alone treatments by without showing any phytotoxicity symptoms on soybean crop.

Improving the quality and toxicity of rice husk liquid smoke to control edamame soybean pests

Purpose of the research to improve the quality and toxicity of husk charcoal liquid smoke which is effective and selective in controlling edamame soybean plant pests, safe for predatory and pollinators arthropods, and does not contain the dangerous compound Benzo(a)pyrene. The resulting product can be used as a substitute for synthetic insecticides which are non-selective and unsafe for predators, pollinators and human health. The technique used was to set the temperature of the pyrolysis process between 200-300°C to produce grade 3 and distillation of grade 3 to grade 2 with a temperature of 80-100°C. Research was carried out at Jember State Polytechnic, from August to September 2023. The observation parameters were content of grade 3 and grade 2 compounds using GCMS, Bioassay tests against S. litura 3rd instar using concentrations of 0%, 1%. 2%, 3%, 4% and 5% each for 10 test insects, with 3 repetitions, using the feed immersion method. LC50 and LC95 test used PoloPlus 1.0. Field tests compared arthropod diversity, grade 3, grade 2 and Imidacloprid treatments, using the Kruskal-Wallis test. The diversity index uses the Shannon-Wiener (H’) and Sympson Dominance Index (C’) formulas. Conclusion LC95 grade 3 was 3%, Grade 2 was 4%. Both were not found Benzo(a)pyrene. The grade 3 pest population was not significantly different compared to Imidacloprid. Grade 3 and grade 2 predators and pollinators were higher than Imidacloprid, the diversity of Grade 3, grade 2 and Imidacloprid treatments were moderate diversity, balanced ecosystem and no species dominance found.

Curcumin and carvacrol co-loaded zein nanoparticles: Comprehensive preparation and assessment of biological activities in pest control

To address the escalating global demand for food production, it is imperative to minimize agricultural losses caused by pests, accounting for up to 40 % of the substantial worldwide losses of 70 billion USD. While conventional pesticides raise environmental concerns, environmentally friendly alternatives like curcumin and carvacrol face low biological activity due to their low solubility and premature degradation in environmental conditions, that is, degradation can occur due to solar radiation, high temperature, etc., before the active ingredients can exert its full potential. This study introduces zein-based nanocarriers encapsulating curcumin and carvacrol, exhibiting favorable characteristics. Cytotoxicity tests indicate approximately 60% viability for fibroblast cell lines compared to 20% for keratinocyte cell lines. The nanoencapsulated compounds exhibit promising biological activity against soybean pests, mites, and caterpillars, without causing phytotoxicity. Tetranychus urticae mortality rates reach 77.1 ± 11.5 %, and nanoencapsulated ingredients demonstrate higher repellency (61.1 ± 8.8%) than emulsified ones (51.1 ± 5.4 %). Nanoencapsulated ingredients exhibit significantly higher mortality rates for Spodoptera cosmioides and Spodoptera eridania, underscoring the potential of nanoencapsulation in bolstering bioactivity against specific pests and promoting sustainable agricultural practices.

Ecological Insights and First Confirmed Record of Ooencyrtus nezarae (Hymenoptera: Encyrtidae) on Eggs of Megacopta cribraria (Hemiptera: Plataspidae) in Tennessee and Georgia1

Abstract The kudzu bug, Megacopta cribraria (F.) (Heteroptera: Plataspidae), is native to Asia, was first detected in Georgia, USA, in 2009, and has since been recognized as a damaging pest of soybean (Glycine max (L.) Merrill; Fabales: Fabaceae) in several southeastern states. Megacopta cribraria dispersed rapidly from 2009 to 2013, after which its spread rate declined sharply. Despite this decline, established populations have remained stable. This decline may be partially attributed to natural enemies of kudzu bug. For example, the exotic egg parasitoids Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Paratelenomus saccharalis (Dodd) (Hymenoptera: Platygastridae) have been occasionally detected in the United States since 2016 and 2013, respectively. We recovered O. nezarae from M. cribraria eggs collected from wild patches of kudzu (Pueraria montana Lour. (Merrill) var. lobata (Willd.)) throughout summer 2017. Although the occurrence of O. nezarae in southern Georgia has been suggested based on exit holes from kudzu bug eggs, to our knowledge, this report is the first to document and confirm recovery of O. nezarae from kudzu bug eggs in both Tennessee and Georgia. In addition, at the time of collection in 2017, this recovery was the first confirmation of this species from kudzu in North America. This early-season natural enemy combined with the later-occurring entomopathogen Beauveria bassiana (Balsamo-Crivelli) Vuillemin may reduce and maintain kudzu bug densities, which could lessen economic impacts on soybean producers.

Identification and expression patterns of somatic piRNAs and PIWI genes in Riptortus pedestris (Hemiptera: Alydidae).

RNA interference (RNAi)-based gene silencing is a feasible and sustainable technology for the management of hemipteran pests by double-stranded RNA involvement, including small-interfering RNA, microRNA, and Piwi-interacting RNA (piRNA) pathways, that may help to decrease the usage of chemical insecticides. However, only a few data are available on the somatic piRNAs and their biogenesis genes in Riptortus pedestris, which serves as a significant pest of soybean (Glycine max). In this study, two family members of the PIWI gene were identified and characterized in R. pedestris, containing Argonaute3 (RpAgo3) and Aubergine (RpAub) genes with conserved protein domains, and their clusters were validated by phylogenetic analysis. In addition, they were widely expressed in all developmental stages of the whole body of R. pedestris and had lower expression levels in R. pedestris guts under different rearing conditions based on previous transcriptome sequencing. Furthermore, abundant clean reads were filtered to a total number of 45,998 piRNAs with uridine bias at the first nucleotide (nt) position and 26-32 nt in length by mapping onto the reference genome of R. pedestris according to our previous whole-transcriptome sequencing. Finally, our data revealed that gut bacterial changes were significantly positively or negatively associated with differentially expressed piRNAs among the five comparison groups with Pearson correlation analysis. In conclusion, these findings paved new avenues for the application of RNAi-based biopesticides for broad-spectrum hemipteran pest control.

Shared phylogeographic patterns and environmental responses of co-distributed soybean pests: Insights from comparative phylogeographic studies of Riptortus pedestris and Riptortus linearis in the subtropics of East Asia

Comparative phylogeographic studies of closely related species sharing co-distribution areas can elucidate the role of shared historical factors and environmental changes in shaping their phylogeographic pattern. The bean bugs, Riptortus pedestris and Riptortus linearis, which both inhabit subtropical regions in East Asia, are recognized as highly destructive soybean pests. Many previous studies have investigated the biological characteristics, pheromones, chemicals and control mechanisms of these two pests, but few studies have explored their phylogeographic patterns and underlying factors. In this study, we generated a double-digest restriction site-associated DNA sequencing (ddRAD-seq) dataset to investigate phylogeographic patterns and construct ecological niche models (ENM) for both Riptortus species. Our findings revealed similar niche occupancies and population genetic structures between the two species, with each comprising two phylogeographic lineages (i.e., the mainland China and the Indochina Peninsula clades) that diverged approximately 0.1 and 0.3 million years ago, respectively. This divergence likely resulted from the combined effects of temperatures variation and geographical barriers in the mountainous regions of Southwest China. Further demographic history and ENM analyses suggested that both pests underwent rapid expansion prior to the Last Glacial Maximum (LGM). Furthermore, ENM predicts a northward shift of both pests into new soybean-producing regions due to global warming. Our study indicated that co-distribution soybean pests with overlapping ecological niches and similar life histories in subtropical regions of East Asia exhibit congruent phylogeographic and demographic patterns in response to shared historical biogeographic drivers.

Molecular characterization and demographic insights into soybean bud borer (Lepidoptera: Tortricidae) in Brazil.

The soybean bud borer, a soybean pest in Brazil, was initially identified as Crocidosema aporema (Walsingham 1914) (Lepidoptera: Tortricidae). Outbreaks of this species have recently increased, but identification of this pest remains uncertain, and the historical factors associated with its geographic distribution in Brazil are little known. Here, we conducted a species characterization and phylogeographic analysis based on molecular and morphological evidence. Ninety individuals of bud-borers Lepidoptera were collected in different regions of Brazil. We sequenced COI and COII mitochondrial genes and examined wing patterns and male genital morphology. DNA barcoding approach revealed that 10 individuals were Argyrotaenia sphaleropa (Meyrick 1909) (Lepidoptera: Tortricidae) and 80 were a species of the genus Crocidosema Zeller. The morphology of the adult genitalia and wings proved to be insufficient to confirm the identification of Brazilian individuals as C. aporema, a species originally described from a high-elevation site in Costa Rica. Furthermore, the genetic distance between putative C. aporema specimens from Brazil and Costa Rica (ranging from 5.2% to 6.4%) supports the hypothesis that the Brazilian specimens are not referable to C. aporema. Our analysis revealed a single genetic strain (i.e., species) with low genetic diversity on soybean crops. We found no indication that the genetic structure was related to geographic distance among populations or edaphoclimatic regions. The population expansion of the soybean bud borer coincides with the increase in the area of soybean production in Brazil, suggesting that expanded soybean farming has allowed a significant increase in the effective population size of this pest.

CRISPR/Cas9-mediated knockout of scarlet gene produces eye color mutants in the soybean looper, Chrysodeixis includens.

The CRISPR/Cas9 technology has greatly progressed research on non-model organisms, demonstrating successful applications in genome editing for various insects. However, its utilization in the case of the soybean looper, Chrysodeixis includens, a notable pest affecting soybean crops, has not been explored due to constraints such as limited genomic information and the embryonic microinjection technique. This study presents successful outcomes in generating heritable knockout mutants for a pigment transporter gene, scarlet, in C. includens through CRISPR/Cas9-mediated mutagenesis. The scarlet locus identified in the genome assembly of C. includens consists of 14 exons, with a coding sequence extending for 1,986 bp. Two single guide RNAs (sgRNAs) were designed to target the first exon of scarlet. Microinjection of these two sgRNAs along with the Cas9 protein into fresh embryos resulted in the successful production of variable phenotypes, particularly mutant eyes. The observed mutation rate accounted for about 16%. Genotype analysis revealed diverse indel mutations at the target site, presumably originating from double-strand breaks followed by the nonhomologous end joining repair, leading to a premature stop codon due to frame shift. Single-pair mating of the mutant moths produced G1 offspring, and the establishment of a homozygous mutant strain occurred in G2. The mutant moths exhibited lightly greenish or yellowish compound eyes in both sexes, confirming the involvement of scarlet in pigmentation in C. includens. Notably, the CRISPR/Cas9-mediated genome editing technique serves as a visible phenotypic marker, demonstrating its proof-of-concept applicability in C. includens, as other pigment transporter genes have been utilized as visible markers to establish genetic control for various insects. These results provide the first successful case that the CRISPR/Cas9 method effectively induces mutations in C. includes, an economically important soybean insect pest.

Seedcorn maggot response to planting date, cover crops, and tillage in organic cropping systems.

Seedcorn maggot, Delia platura (Meigen) (Diptera: Anthomyiidae), is an economically important early-season pest of corn and soybean in the United States. Adult seedcorn maggot is attracted to decomposing plant residues for oviposition, creating potential management issues where growers typically use tillage to incorporate fertility amendments and to create a seedbed. The use of growing degree-day models to time planting dates is an important tool for effectively managing this pest, but their use has not been examined in organic crop production. Here, we report the results of experiments to determine the effects of cover crops, tillage, and relative planting date on seedcorn maggot in corn and soybean in 2 experiments: The first during the transition to organic from conventional management and the second during the 3 yr following organic certification in central Pennsylvania, United States. Overall, delaying the planting date by 1-2 wk reduced fly emergence in corn, but not in soybean in both experiments. Seedcorn maggot emergence was also consistently greater in corn than in soybean, with 6 times more flies in corn than in soy. About 15 times more seedcorn maggot flies emerged from corn in treatments in which cover crops were managed with tillage compared to treatments in which cover crops were terminated with a roller-crimper followed by no-till planting of corn. Fly emergence was negatively related to the proportion of legumes in the cover crop mixture preceding corn. These results can help inform soil, cover crop, and crop decisions for organic growers in the Mid-Atlantic United States.

Overwintering site selection and associated microclimates for the redbanded stink bug (Hemiptera: Pentatomidae), a non-native pest of soybean.

Cold winter temperatures govern the distribution and abundance of many insect species, but refugia that provide microclimates can moderate temperature-driven mortality. Winter temperatures have been implicated in limiting the survival and range of Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae; redbanded stink bug), an economically damaging invasive pest in the southeastern United States, but the role of refugia in overwintering survival of this pest is poorly understood. We conducted 2 studies in successive years to evaluate how leaf litter from hardwoods, pines, and soybeans modulate overwintering site selection and survival of P. guildinii. In the second-year study, we also quantified the buffering effect of the 3 leaf litter types compared to ambient conditions and assessed diapause. In the first-year study, we found that stink bugs preferentially dispersed into leaf litter compared with remaining unsheltered on bare soil; no clear preference among leaf litter types was found. In the second year, however, no clear differences were found among leaf litter types and bare soil. Means of daily minimum temperatures under leaf litter were at least 3.0 ± 0.9 °C (SE) warmer and generally less variable than ambient conditions. While high mortality in both studies illustrates that more work must be done to fully understand overwintering survival, limited survival through potentially lethal conditions in the first-year study nonetheless emphasizes the possibility of populations persisting and rebounding in the following spring. Furthermore, our study highlights the potential for stink bugs to persist in areas with lethal ambient temperatures by dispersing into widely available substrates.

Utilizing Remote Sensing to Quantify the Performance of Soybean Insecticide Seed Treatments

Soybean (Glycine max) is one of the most important oilseed crops grown in North America and a key contributor to the global protein supply. Insect feeding by a major soybean pest, the bean leaf beetle (BLB; Cerotoma trifurcata), can result in economic yield loss if not controlled. The objective of this research was to use unmanned aerial vehicle (UAV) image analysis to compare the agronomic and efficacy traits of two soybean insecticide seed treatments (IST) in locations with BLB feeding. Across the 2018–2023 field trial locations, 29 had low BLB feeding pressure (less than 25% feeding damage to no IST plots) and 31 had high BLB feeding pressure (greater than 25% feeding damage to no IST plots). In low BLB pressure locations, cyantraniliprole and imidacloprid seed treatments had significantly higher BLB efficacy, significantly higher UAV greenness, and significantly higher final yield as compared to no IST. In high BLB pressure locations, cyantraniliprole and imidacloprid seed treatments were significantly better compared to no IST for BLB efficacy, UAV emergence, UAV vigor, UAV greenness, and final yield. In high BLB pressure locations, cyantraniliprole had significantly higher BLB efficacy, significantly better UAV emergence, and significantly higher yield compared to imidacloprid. The cyantraniliprole treatment had a +254.5 kg/ha increase compared to no IST in low BLB pressure locations and a +213.7 kg/ha increase in high BLB pressure locations. The imidacloprid treatment had a +163.4 kg/ha yield increase compared to no IST in low BLB pressure locations and a +121.4 kg/ha yield increase in high BLB pressure locations. The use of UAV image analysis enabled quantification of the effect of BLB feeding on early-season agronomic traits and, when combined with efficacy and final yield data, successfully differentiated the performance of two soybean ISTs in environments with low or high insect pressure.

Using mung bean as a trap crop and biopesticide for control of soybean pest

Many pests attack soybean plants and can cause high-yield losses. To reduce crop damage, using chemicals in the field can potentially cause harmful effects on the environment. Using traps-crops, and biopesticides will be tested as an effective and safe control method. The research was done in the dry season of the tidal land of Tumih Village South of Kalimantan. The design used was RCBD which consisted of six treatments and was repeated four times. The treatment tested were 1). Check, 2). Biopesticides 6 times, 3). Biopesticide 4 times, 4). Biopesticides 6 times + mung bean as trap crop 6%, 5). Biopesticides 4 times + mung bean as trap crop 6%, 6. Insecticides 6 times. The results indicated that armyworms Spodoptera litura and Lamprosema indicata were important pests. Armyworm attacks in the vegetative phase reached 82%. However, the yields obtained were around 2,069 to 2,463 t/ha. Soybean yields in treatment plots with 6% trap crop were 1,664 to 1,969 t/ha. Anjasmoro varietal is not recommended In endemic areas of the armyworm.

YOLO performance analysis for real-time detection of soybean pests

In this work, we evaluated the You Only Look Once (YOLO) architecture for real-time detection of soybean pests. We collected images of the soybean plantation in different days, locations and weather conditions, between the phenological stages R1 to R6, which have a high occurrence of insect pests in soybean fields. We employed a 5-fold cross-validation paired with four metrics to evaluate the classification performance and three metrics to evaluate the detection performance. Experimental results showed that YOLOv3 architecture trained with a batch size of 32 leads to higher classification and detection rates compared to batch sizes of 4 and 16. The results indicate that the evaluated architecture can support specialists and farmers in monitoring the need for pest control action in soybean fields.

Control Effects of Short-Term Heatwaves on a Holocyclic Aphid.

The soybean aphid, A. glycines, is an important soybean pest. Harbin, in the Heilongjiang Province, is an area with increasing temperatures in China that faces frequent short-term heatwaves. In this study, the development, reproduction, and morph differentiation of A. glycines have been studied when they were exposed to diurnal at 35 °C for seven days, beginning at different developmental stages. The nymph stage duration of A. glycines was longer, the adult lifespans and total lifespans were shorter, and their bodies were smaller when exposed to a diurnal of 35 °C beginning at the 1st to 4th stadium. The adult reproduction period was shorter, and the adult fecundity and intrinsic rate of increase were smaller than those of aphids reared at a diurnal of 25 °C. A higher and lower proportion of gynoparae and males were deposited as offspring on day 13 by adults when exposed to diurnal at 35 °C, beginning at the 1st to 4th stadium, respectively, than those of aphids reared at a constant of 20 °C. These results are important for predicting the dynamics of A. glycines in Harbin soybeans. This provides evidence that short-term heatwaves are probably useful for controlling A. glycines, by inhibiting development and male morphogenesis.

Why does identification matter? Thrips species (Thysanoptera: Thripidae) found in soybean in southern Brazil show great geographical and interspecific variation in susceptibility to insecticides

Thrips have historically been considered secondary soybean pests in Brazil and neighboring countries. However, since the 2010s they have gained importance in soybean in central and northern Brazil. From 2017 onwards, high infestations of thrips have also been detected in soybean in southern Brazil. Here, we collected and identified thrips species from soybean fields in southern Brazil throughout the 2022/2023 season and conducted laboratory bioassays to assess their susceptibility to selected insecticides. Thrips were exposed to the field concentrations of selected insecticides in leaf-dip bioassays using soybean leaves. Our results indicated that Frankliniella schultzei (Trybom, 1910) and Caliothrips phaseoli (Hood, 1912) are the major thrips species found in soybean in southern Brazil. These species exhibited high mortality and relatively low geographic and interspecific variation in susceptibility to the field concentrations of spinetoram, methomyl, spinetoram + methoxyfenozide and profenofos + cypermethrin. In general, most populations of C. phaseoli were more susceptible to acephate, chlorfenapyr and abamectin than F. schultzei, whereas bifenthrin + carbosulfan showed high lethality against most populations of F. schultzei, however, both species had wide geographic variation in susceptibility to these chemistries. In contrast, populations of both species have low mortality when exposed to the field concentrations of imidacloprid, lambda-cyhalothrin and lambda-cyhalothrin + sulfoxaflor. In summary, our study documents significant variations in the susceptibility of F. schultzei and C. phaseoli to selected insecticides, both among species and among geographical areas across southern Brazil. These results highlight the importance of species identification for the effective control of thrips in soybean in Brazil and other South American countries.

Agricultural issues with climate change—case studies with 3 soybean pests: Johnsongrass, kudzu bug, and charcoal rot

Abstract Agricultural production and crop yields are threatened around the world by the emergence and spread of agronomical pests, including diseases, insects, and weeds. Due to changes in precipitation, carbon dioxide levels, and warming temperatures being experienced throughout most of the world, new challenges are emerging for pest management in virtually all major cropping systems. While precise environmental impacts due to climate change are impossible to predict, they will require innovative and new solutions for pest management. In this article, we explore the challenges of 3 problem pest species with soybean: Johnsongrass, kudzu bug, and charcoal rot. Understanding pest responses to climate change is vital for better understanding the new agricultural innovations that will be required to manage them in the future.

Effect of varieties and applications of clove oil on growth, productivity, and pest and disease resilience of soybean

Efforts to increase soybean productivity are carried out in various ways, including improving cultivation technology and applying pest and disease control technologies for soybeans. In addition to chemical pesticides, pest and disease control can use botanical pesticides or biopesticides, including those made from clove oil. This study aimed to determine the effect of varieties and clove oil on the growth, production, and pest-disease resilience of soybean. The study was conducted at Majalengka Regency, West Java, Indonesia from April to July 2021. The research used a factorial randomized complete block design with four replications. The first factor was soybean genotypes: Dena 1, Dega 1, and Anjasmoro. The second factor was the concentration and interval of application of clove oil: control, 3 mL L-1 with an interval of 10 days, 3 mL L-1 with an interval of 15 days, 5 mL L-1 with an interval of 10 days, and 5 mL L-1 with an interval of 15 days. The results showed that the Dena 1 variety had the highest plant height, number of branches, number of pods per plant, and dry weight per plant. The Dega 1 variety produced the highest weight of plant dry mass, dry pod shell weight, and 100-grain. Anjasmoro variety had the highest root length and number of nodules per plant. The Anjasmoro was more resistant to leaf caterpillar attacks, while the Dena 1 was more resistant to leaf rust disease. Botanical pesticides derived from clove oil affected various aspects of soybean growth including plant height at 60 days after planting, weight of dry biomass, root length and number of root nodules per plant, dry pod shell weight, dry seed weight, and 100-grains weight.
 Keywords: botanical pesticide; clove oil; Glycine max; root nodulation; variety