Search

BackgroundThe sweet potato whitefly (Bemisia tabaci) is a globally important insect pest that damages crops through direct feeding and by transmitting viruses. Current B. tabaci management revolves around the use of insecticides, which are economically and environmentally costly. Host plant resistance is a sustainable option to reduce the impact of whiteflies, but progress in deploying resistance in crops has been slow. A major obstacle is the high cost and low throughput of screening plants for B. tabaci resistance. Oviposition rate is a popular metric for host plant resistance to B. tabaci because it does not require tracking insect development through the entire life cycle, but accurate quantification is still limited by difficulties in observing B. tabaci eggs, which are microscopic and translucent. The goal of our study was to improve quantification of B. tabaci eggs on several important crop species: cassava, cowpea, melon, sweet potato and tomato.ResultsWe tested a selective staining process originally developed for leafhopper eggs: submerging the leaves in McBryde's stain (acetic acid, ethanol, 0.2% aqueous acid Fuchsin, water; 20:19:2:1) for three days, followed by clearing under heat and pressure for 15 min in clearing solution (LGW; lactic acid, glycerol, water; 17:20:23). With a less experienced individual counting the eggs, B. tabaci egg counts increased after staining across all five crops. With a more experienced counter, egg counts increased after staining on melons, tomatoes, and cowpeas. For all five crops, there was significantly greater agreement on egg counts across the two counting individuals after the staining process. The staining method worked particularly well on melon, where egg counts universally increased after staining for both counting individuals.ConclusionsSelective staining aids visualization of B. tabaci eggs across multiple crop plants, particularly species where leaf morphological features obscure eggs, such as melons and tomatoes. This method is broadly applicable to research questions requiring accurate quantification of B. tabaci eggs, including phenotyping for B. tabaci resistance.

Elicitor-induced defences are a new addition in plants’ armour to counter insect herbivory. It is unknown whether exogenously-applied jasmonic acid and salicylic acid (JA & SA) induced defence in pigeonpea (Cajanus cajan) can reduce Maruca vitrata (Fab.) herbivory. We exogenously treated one resistant (AL 1747) and one susceptible (MN 1) pigeon pea genotype with JA (100 µM) and SA (5 mM) at 50% flowering stage (five treatments each). Then, we quantified pigeon pea secondary plant metabolites and M. vitrata nutritional indices. Approximate digestibility, efficiency of conversion of ingested and digested food into body matter, and relative growth rate of M. vitrata larvae were significantly reduced on plants pre-treated with JA and then infested with M. vitrata (PJA + MV); however, consumption index was increased. SA applications also altered the nutritional indices of M. vitrata, but the effects were not as pronounced as JA applications. PJA + MV treatment rapidly increased the level of tannins, total phenols and total protease inhibitors in flowers of both genotypes one day after treatment (DAT); this induction was more noticeable in the resistant genotype. However, only constitutive levels of the aforesaid compounds were detected at 7 DAT. Thus, JA and SA can significantly enhance pigeonpea defences against M. vitrata, providing farmers with an environmentally friendly alternative to synthetic pesticides. Researchers can further explore the use of natural or synthetic elicitors in integrated pest management, potentially combining them with biological control. [ABSTRACT FROM AUTHOR]

Current practices of flea beetle (Phyllotreta spp.) control in Brassica napus L. rely heavily on seed treatments and due to growing concerns regarding the safety of such treatments on non-target and beneficial insect populations, genetic resistance would be beneficial for a more balanced integrated pest management strategy. However, none of the registered B. napus. canola varieties exhibit measurable resistance to flea beetle injury. To this end, an evaluation of 14 winter-type B. napus breeding lines and 15 spring-type B. napus breeding lines for resistance to flea beetle feedings was conducted, as it was found that at least one line in each family exhibited noticeably reduced flea beetle damage compared to sister lines in a breeding nursery. The study revealed natural genetic variation within B. napus for flea beetle antixenosis which could be used by dedicated breeders to develop canola varieties with higher levels of flea beetle resistance. Data indicated that host plant resistance did not vary between feeding by newly emerged adult flea beetles in the fall and the overwintered adults in the spring in either winter-type or spring-type canola, as well as for adult feeding preferences. This indicates that favourable genes identified in in either habitat-type could be used interchangeably to confer resistance even though the flea beetle life cycle is different for each planting period, while either overwintered adults or newly emerged adults can be used to evaluate feeding damage. [ABSTRACT FROM AUTHOR]

The annual bluegrass weevil (Listronotus maculicollis) is the most damaging insect pest of short-mown turfgrass on golf courses in eastern North America. Listronotus maculicollis larvae cause limited visible damage as stem-borers (L1-3), compared to the crown-feeding (L4-5) developmental instars. Prolonged larval feeding results in discoloration and formation of irregular patches of dead turf, exposing soil on high-value playing surfaces (fairways, collars, tee boxes, and putting greens). Annual bluegrass (Poa annua) is highly susceptible to L. maculicollis compared to a tolerant alternate host plant, creeping bentgrass (Agrostis stolonifera). This study explored whether defense signaling phytohormones contribute to A. stolonifera tolerance in response to L. maculicollis. Concentrations (ng/g) of salicylic acid (SA), jasmonic acid (JA), jasmonic-isoleucine (JA-Ile), 12-oxophytodienoic acid (OPDA), and abscisic acid (ABA) were extracted from turfgrass (leaf, stem, and root) tissue samples as mean larval age reached 2nd (L2), 3rd (L3), and 4th (L4) instar. Poa annua infested with L. maculicollis larvae (L2-4) possessed significantly greater SA in above-ground tissues than A. stolonifera. Levels of constitutive JA, JA-Ile, OPDA, and ABA were significantly higher within non-infested A. stolonifera aboveground tissues compared to P. annua. Inducible defense phytohormones may play a role in P. annua susceptibility to L. maculicollis but are unlikely to provide tolerance in A. stolonifera. Additional studies in turfgrass breeding, particularly focusing on cultivar selection for increased constitutive JA content, could provide a non-chemical alternative management strategy for L. maculicollis for turfgrass managers. [ABSTRACT FROM AUTHOR]

Simple Summary: Rice breeding programs have included traditional varieties and wild rice species as sources of resistance to planthoppers and leafhoppers, which are major insect pests of rice in Asia. However, herbivores can adapt to resistance (known as virulence adaptation), sometimes in as little as 2 years. Virulence adaptation is a major obstacle for deploying resistant varieties. This review assesses knowledge of the rates, consequences, and mechanisms of virulence adaptation and on possible strategies to delay adaptation in rice landscapes. The review indicates that virulence is a complex of responses to minor and major resistance factors. Of particular interest are adaptations to major rice resistance genes that are likely governed by corresponding herbivore virulence genes. Evidence suggests that pre-adapted individuals (called forerunners) with these virulence genes occur in planthopper populations at relatively low frequencies but can rapidly build up numbers in response to planted resistant rice. However, gradual shifts in virulence may also occur due to intra- and intergenerational improvements in the herbivores' abilities to detoxify plant defense toxins, or to confound defense response networks. These may involve gradual changes in the expression of genes involved in successful herbivore attacks and may be associated with the herbivores or their endosymbionts. Several research gaps remain. In particular, there is a need for increased attention to practical, ecologically based deployment strategies that delay adaptation. In recent decades, research on developing and deploying resistant rice has accelerated due to the availability of modern molecular tools and, in particular, advances in marker-assisted selection. However, progress in understanding virulence adaptation has been relatively slow. This review tracks patterns in virulence adaptation to resistance genes (particularly Bph1, bph2, Bph3, and bph4) and examines the nature of virulence based on selection experiments, responses by virulent populations to differential rice varieties (i.e., varieties with different resistance genes), and breeding experiments that interpret the genetic mechanisms underlying adaptation. The review proposes that varietal resistance is best regarded as a combination of minor and major resistance traits against which planthoppers develop partial or complete virulence through heritable improvements that are reversable or through evolutionary adaptation, respectively. Agronomic practices, deployment patterns, and herbivore population pressures determine the rates of adaptation, and there is growing evidence that pesticide detoxification mechanisms can accelerate virulence adaptation. Research to delay adaptation has mainly focused on gene pyramiding (i.e., including ≥ two major genes in a variety) and multilines (i.e., including ≥ two resistant varieties in a field or landscape); however, these strategies have not been adequately tested and, if not managed properly, could inadvertently accelerate adaptation compared to sequential deployment. Several research gaps remain and considerable improvements in research methods are required to better understand and manage virulence adaptation. [ABSTRACT FROM AUTHOR]

Asian rice gall midge is one of the important pests of rice, which attacks the crop from nursery to the end of the tillering stage. Managing this pest through plant resistance is the most viable and economical. Two hundred‐two rice genotypes were phenotyped against Asian rice gall midge, Orseolia oryzae (Wood‐Mason) and the mechanism of resistance in terms of antixenosis and antibiosis was studied. Antixenosis mechanism for adult settlement and egg laying indicated that the susceptible genotypes were preferred more than the resistant genotypes in a free choice test. First instar maggots were found and did not continue their growth on resistant genotypes further. However, in susceptible genotypes, they molted successfully and emerged as adults. No choice tests revealed that the emergence of adults in susceptible genotypes took less time than in resistant genotypes. Higher adult sex ratio was found in susceptible genotypes. Estimation of biochemical components in rice shoot apices of selected genotypes revealed that higher levels of total phenols, wax content, total flavonoids and total free amino acids were present in the resistant genotypes. Still, the number of total sugars, reducing sugars and total protein contents were significantly higher in the susceptible genotypes. Hence, the resistance mechanism in rice gall midge was displayed as a combination of antixenosis and antibiosis mechanism. The output of the study would be helpful in breeding for rice varieties resistant to Asian rice gall midge. [ABSTRACT FROM AUTHOR]

Sterility mosaic disease (SMD) presents a major challenge in pigeonpea cultivation throughout the Indian subcontinent. Chemical control methods, such as acaricides, are neither economically viable nor sustainable, making host plant resistance the preferred approach for managing this disease. In this study, we evaluated 45 pigeonpea germplasm accessions and breeding lines for SMD resistance over two consecutive Kharif seasons (2021-22 and 2022-23). Of the 45 genotypes tested, 8 exhibited low disease incidence (0-10%) (LRG-471, ICPL 151, ICPB 2089, ICPB 2047, ICPB 2092, ICPB 2211, ICPL 85063, and ICPL 14003) and were classified as resistant. Additionally, 23 genotypes showed disease incidence between 10.1-20.0% and were categorized as moderately resistant. These resistant genotypes offer promising new sources of SMD resistance and should be considered for inclusion in future pigeonpea breeding programs aimed at improving resistance. This research provides valuable phenotypic insights and identifies stable resistant sources essential for advancing SMD resistance breeding efforts. [ABSTRACT FROM AUTHOR]

Castor is an important oilseed crop grown in India. However, its cultivation is seriously affected by several diseases, e.g. wilt disease caused by Fusariumoxysporum f. sp. ricini being economically relevant. Host plant resistance is the best option for the management of this disease. A total of 524 castor genotypes were screened against wilt disease under sick plot conditions for five years from 2013–2014 to 2017–2018. The wilt sick plot was maintained with a inoculum load of 2 × 103 CFU/gm of soil and the genotypes were screened alongside resistant (48–1) and susceptible (JI-35) cultivars. It was observed that 109 castor genotypes were susceptible to wilt with more than 50% wilt incidence whereas, 32 genotypes; i.e., DCS-86, DCS-118, DCS-108, DCS-105, DCS-107, DPC-17, DPC-18, DPC-21, DPC-23, DPC-24, DPC-25, M-571, DPC-28, PMC-9, PMC-11, PMC-14, PMC-15, PMC-16, PMC-17, PMC-24, PMC-38, PMC-55, PMC-60, PVT- 11–3, PVT-11–18, PVT-11–17, PVT-11–21, PVT-12–4, PVT-12–6, PVT-12–72 and PVT-11–26 recorded < 20% wilt incidence during the consecutive years of testing. Three wilt-resistant parental lines of castor IPC-21/DPC-21(INGR No.21107), M-571 (INGR No. 21230), and ICS-200 (INGR No. 21157) were identified and registered by the Plant Germplasm Registration Committee. Among the screened parental lines, PMC-14 showed a resistant reaction of 10–16.7% to wilt for three years and was used as a parent ICS-164 (PMC-14) in developing wilt-resistant hybrid ICH-66, which was released for cultivation in five states of India, namely, Andhra Pradesh, Telangana, Tamil Nadu, Karnataka and Odisha. The resistant lines identified in this study could be used for breeding wilt-resistant castor hybrids. [ABSTRACT FROM AUTHOR]

Abstract Plants are attacked by diverse herbivorous pests with different host specializations. While host plant resistance influences pest pressure, how resistance impacts the behaviors of generalist and specialist herbivores, and the relationship to resistance, is less well known. Here, we investigated the short-term (

Helicoverpa armigera (Hübner) is one of the invasive pests of crops worldwide, and several studies have focused to compare the growth, consumption, and digestion of H. armigera larvae on different plants. However, studies evaluating the insect’s food consumption and digestive physiological response using biochemical profile of sunflower cultivars are scarce. In this research, the impacts of various sunflower cultivars (Golsa, Ghasem, Shams, and Zarrin) based on artificial diet were evaluated on enzymes activity and nutritional responses of H. armigera. Among the different sunflower cultivars, the relative growth rate (RGR), efficiency of conversion of ingested food (ECI), and efficiency of conversion of digested food (ECD) were highest on Ghasem. Likewise, the heaviest weight of larvae and pupae was obtained on Ghasem, while the lightest was found on Zarrin. The highest proteolytic activity was detected on Zarrin, whereas the highest amylolytic activities were found on Ghasem and Shams. In addition, ECD and RGR values of H. armigera larvae were negatively correlated with secondary metabolites content (phenol). The cluster analysis revealed that Ghasem was a nutritionally appropriate cultivar for H. armigera, while Zarrin illustrated the greatest level of tolerance against this polyphagous pest. These results could be useful in selection of sunflower cultivars for cultivation and breeding programs that entail H. armigera control.

UASD Bt cotton Event-78 based early segregating generations (F2 & F3) derived from three diverse crosses were evaluated for field incidence of cotton leaf hopper during kharif-2021 & 2022 at Agricultural Research Station, UAS, Dharwad. A total 600 F2 plants from the crosses viz., UASD Bt-78 х DHS-29, UASDBt-78 х Suvin and Suvin х UASD Bt-78 were screened of which 103,100 and 102 plants respective to the three crosses were found to be resistant. The segregation of F2 population for the jassid tolerance deciphered the implicit “Inhibitory epistasis” mechanism of host plant resistance. Further evaluation of F3 families of these crosses leads to identification of 103 resistant lines from all the three crosses, the mean leafhopper population ranges from 0.67- 2.67 leafhoppers / 3 leaves with the LHRI score of 1.

Abstract Background Cotton (Gossypium hirsutum L.) is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies. However, over the years quantity and quality have been hampered by the pest leafhopper. Leafhopper alone has been shown to cause yield losses of up to 40%. In this study, screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant, moderately resistant, sensitive and highly sensitive to leafhoppers. Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance. Based on the screening results, a total of 19 genotypes were resistant to leafhoppers, which was on par with the findings of the check KC 3. The contents of total soluble sugar, total soluble protein, and total free amino acids were significantly positively correlated with the mean grade, whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade. However, based on screening and biochemical analysis, the genotypes KC 2, JR-23, Samaru-26-T, D 4, TCH 1728, RS 253, and B-61-1862 exhibited high resistance to leafhopper. Conclusion According to the findings of this study, choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar, total soluble protein, and free amino acids may aid in the development of resistant genotypes.

Plants are attacked by diverse herbivorous pests with different host specializations. While host plant resistance influences pest pressure, how resistance impacts the behaviors of generalist and specialist herbivores, and the relationship to resistance, is less well known. Here, we investigated the short-term (< 1 h) behavioral changes of a generalist herbivore, the two-spotted spider mite (TSM), and a specialist herbivore, the Banks grass mite (BGM), after introduction to no-choice Tanglefoot leaf-arenas (2 × 2 cm) of three maize inbred lines (B73, B75, and B96). The widely-used inbred line B73 is susceptible to spider mites, while B75 and B96 are known to be mite resistant, especially to TSM. Video tracking was used to record TSM and BGM walking, probing, feeding, resting, web-building and travel distance on arenas of each line. Mite oviposition was also recorded after 72 h. B75, a resistant line, decreased the feeding behavior (i.e., time) of both mite species compared to B73 (susceptible control) and B96. Moreover, TSM appeared to be sensitive to both resistant lines (B75 and B96) with reduced oviposition, and increased resting and web-building times compared to susceptible B73. In contrast, the specialist BGM showed no difference in oviposition, resting and web-building time across all maize inbred lines. Our findings of quite broad and short-term responses of TSM to B75 and B96 are consistent with a role for constitutive or rapidly induced plant defenses in maize in conferring TSM resistance. Other mechanisms of plant resistance may be needed, however, for defense against specialists like BGM. [ABSTRACT FROM AUTHOR]

Background: Cotton (Gossypium hirsutum L.) is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies. However, over the years quantity and quality have been hampered by the pest leafhopper. Leafhopper alone has been shown to cause yield losses of up to 40%. In this study, screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant, moderately resistant, sensitive and highly sensitive to leafhoppers. Results: A total of hundred genotypes were evaluated along with five checks for leafhopper resistance. Based on the screening results, a total of 19 genotypes were resistant to leafhoppers, which was on par with the findings of the check KC 3. The contents of total soluble sugar, total soluble protein, and total free amino acids were significantly positively correlated with the mean grade, whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade. However, based on screening and biochemical analysis, the genotypes KC 2, JR-23, Samaru-26-T, D 4, TCH 1728, RS 253, and B-61-1862 exhibited high resistance to leafhopper. Conclusion: According to the findings of this study, choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar, total soluble protein, and free amino acids may aid in the development of resistant genotypes. [ABSTRACT FROM AUTHOR]

Simple Summary: Hybrid rice is grown by millions of Asian farmers and has normally higher yields compared to inbred varieties. However, hybrid rice has been associated with high damage from herbivores. This susceptibility could be due to the physiology of the hybrid plant type or due to a limited availability of male sterile parents that are necessary for hybrid seed production. We examined how plant type and breeding affect the relative susceptibilities of hybrid and inbred rice by exposing 32 rice genotypes to the brown planthopper, whitebacked planthopper, and yellow stemborer in controlled environments and field plots. We compared insect fitness on the plants and related this to the type and genetic similarity of genotypes. Despite their diverse origins (China, Colombia, India, and the Philippines), the hybrids and inbreds formed two distinct genetic groups, thereby confounding plant type and phylogeny. Hybrids were generally more susceptible to stemborers but not to planthoppers. Relative herbivore fitness was strongly influenced by plant origin (i.e., breeding program) with one group of related genotypes being relatively susceptible to all three herbivores. Our results indicate that hybrids are not inherently more susceptible than inbreds to insect herbivores and that careful screening with the elimination of the most susceptible genotypes is necessary to reduce herbivore damage to hybrid and inbred rice in Asia. Several studies have reported higher damage from insect herbivores to hybrid compared to inbred (pure line) rice. We used a collection of 20 hybrid and 12 inbred genotypes from diverse origins to test the hypotheses that hybrid rice susceptibility is due to (a) the hybrid plant type and/or (b) rice phylogeny. We challenged the genotypes with Nilaparvata lugans (BPH), Sogatella furcifera (WBPH) and Scirpophaga incertulas (YSB) in greenhouse and screenhouse bioassays and monitored herbivores in field plots. We used single nucleotide polymorphic (SNP) markers to assess genetic similarities between the genotypes and found that the hybrids and inbreds formed two distinct clusters regardless of origin. In the screenhouse, hybrids were more susceptible than inbreds to YSB; however, resistant hybrids and susceptible inbreds were also apparent from both the screenhouse and field plots. Plant biomass was the best predictor of susceptibility to YSB. Plant origin had a greater effect than plant type on susceptibility to BPH and WBPH. WBPH was the most abundant planthopper in the field plots where numbers were highly correlated with planthopper fitness in the greenhouse bioassays. Our results provide evidence that high-yielding hybrids that are relatively resistant to herbivores can be achieved through careful breeding. The avoidance of susceptible genotypes during breeding should remain a key element of integrated rice pest management. [ABSTRACT FROM AUTHOR]

Non-insecticidal control strategies using entomopathogens, nematodes, and endophytes provide sustainable and safer alternatives for managing crop pests. This study investigated the potential of different fungal endophytes, specifically Beauveria bassiana strains, in colonizing cotton plants and their efficacy against tarnished plant bug, Lygus lineolaris. The effect of endophytes on plant growth parameters and cotton yield were measured during different plant growth stages. The entomopathogenicity of these fungi was studied in diet cup bioassays using L. lineolaris adults. The behavior of adult males and females toward endophytic cotton squares was analyzed using olfactometer assays. The experiments showed that the fungal endophytes colonized the plant structures of cotton plants, which resulted in an increase in the number of cotton squares, plant height, and weight compared to control plants. B. bassiana strains/isolates such as GHA, NI-8, and JG-1 caused significant mortality in Lygus adults compared to controls. Also, male and female Lygus adults exhibited repellence behavior towards endophytic cotton squares containing JG-1 isolate of B. bassiana and to other B. bassiana strains such as NI-8, GHA, and SPE-120. No differences were observed in the survival and development of L. lineolaris second-instar nymphs on endophytic cotton, and no yield differences were observed in the field experiments. [ABSTRACT FROM AUTHOR]

The stability of host plant resistance to insects, and efficacy of insecticides against the insect pests is influenced by several inherent traits of the target insects in addition to the environmental factors. Spotted stem borer, Chilo partellus (Swinhoe) is a key pest of maize and sorghum. It undergoes both hibernation and aestivation depending upon the prevailing climatic conditions. We studied the host preference and damage potential of this pest in maize and sorghum, and its susceptibility to different insecticides in F1 progenies of hibernating, aestivating and nondiapausing strains of C. partellus. The larvae from hibernating strain resulted in greater leaf damage and deadhearts, and had greater larval weight and better survival on maize and sorghum than those from the aestivating and nondiapausing strains, although there were a few exceptions. The susceptible maize and sorghum genotypes were highly preferred by the hibernating larvae, while the resistant genotypes were preferred most by the aestivating strain. Maize was least preferred, while sorghum was most preferred by the larvae from hibernating as compared to aestivating and nondiapausing strains of C. partellus. The larvae from aestivating strain were least susceptible to cypermethrin and thiamethoxam, but highly susceptible to deltamethrin and imidacloprid as compared to the other strains. The present studies showed significant differences in preference and damage potential in the host crops, and susceptibility to insecticides in diapausing and nondiapausing strains of C. partellus. Identification of stem borer resistant genotypes of sorghum and maize, and the insecticides with stable efficacy will be useful for integrated management of this pest. [ABSTRACT FROM AUTHOR]

Whitefly-transmitted viruses have emerged as a major threat to cucurbit production in the United States during the past several decades. Cucurbit chlorotic yellows virus (CCYV), Cucurbit yellow stunting disorder virus (CYSDV), and Cucurbit leaf crumple virus (CuLCrV) are the main arthropod-borne plant viruses in cucurbit crops, including yellow squash (Cucurbita pepo). Symptoms of these viruses include interveinal chlorosis, chlorotic spots, yellowing, and curling of the leaves. The evaluation of specific viruses affecting a plant is challenging because of the prevalence of mixed infections in naturally infected fields. To devise an efficient breeding-based management approach, two PI lines (PI 171625 and PI 171627) were screened in a greenhouse to assess their resistance to individual infections of CCYV and CuLCrV. These lines were compared against a susceptible cultivar Gentry in two separate trials. PI 171627 displayed delayed symptoms, a reduced virus load, and a smaller area under the disease progress curve (AUDPC) compared with PI 171625 and susceptible cultivar Gentry when the plants were infected with CCYV. However, the AUDPC for CuLCrV was the same for both genotypes and the commercial line. Accession PI 171627, which displayed delayed and milder symptoms, could potentially provide a source for resistance against CCYV for breeding program. Future research is needed to comprehend the underlaying mechanism to understand this response. [ABSTRACT FROM AUTHOR]

Helicoverpa armigera (Hübner) is one of the invasive pests of crops worldwide, and several studies have focused to compare the growth, consumption, and digestion of H. armigera larvae on different plants. However, studies evaluating the insect's food consumption and digestive physiological response using biochemical profile of sunflower cultivars are scarce. In this research, the impacts of various sunflower cultivars (Golsa, Ghasem, Shams, and Zarrin) based on artificial diet were evaluated on enzymes activity and nutritional responses of H. armigera. Among the different sunflower cultivars, the relative growth rate (RGR), efficiency of conversion of ingested food (ECI), and efficiency of conversion of digested food (ECD) were highest on Ghasem. Likewise, the heaviest weight of larvae and pupae was obtained on Ghasem, while the lightest was found on Zarrin. The highest proteolytic activity was detected on Zarrin, whereas the highest amylolytic activities were found on Ghasem and Shams. In addition, ECD and RGR values of H. armigera larvae were negatively correlated with secondary metabolites content (phenol). The cluster analysis revealed that Ghasem was a nutritionally appropriate cultivar for H. armigera, while Zarrin illustrated the greatest level of tolerance against this polyphagous pest. These results could be useful in selection of sunflower cultivars for cultivation and breeding programs that entail H. armigera control. [ABSTRACT FROM AUTHOR]

Simple Summary: The sweetpotato whitefly, Bemisia tabaci Gennadius Middle East–Asia Minor 1 (MEAM1), is an economically important vegetable worldwide. This study evaluated the susceptibilities of yellow squash and zucchini cultivars to MEAM1 across three growing seasons in the southeastern United States: summer 2021, fall 2021, and fall 2022. Commercially available cultivars squash and zucchini were examined for resistance to MEAM1 infestations and yield performance. Weekly MEAM1 adult, egg, and nymph counts were conducted over 5 (fall 2022) or 6 (summer and fall 2021) weeks beginning after the third week of planting in each season. In general, MEAM1 adult populations were high at the first week of sampling but decreased in the subsequent weeks. The Zucchini cultivar 'Black Beauty' had the highest number of MEAM1 adults, and 'Green Eclipse Zucchini' had the lowest adult counts in summer 2021. For yellow squash, 'Early Summer' and 'Amberpic 8455' were identified as the cultivars that harbored the highest populations of adults in 2021, whereas 'Golden Goose Hybrid' harbored the least number of adult infestations in fall 2022. Generally, MEAM1 egg counts trailed adult peak populations. For yield performance, 'Gourmet Gold Hybrid', 'Lioness', 'Fortune', and 'Golden Glory' achieved the highest yields. These results provide valuable information for whitefly management in yellow squash and zucchini based on host plant resistance and yield. The sweetpotato whitefly, Bemisia tabaci (Gennadius) Middle East–Asia Minor 1 (MEAM1), causes significant losses to vegetable crops directly by sap-feeding, inducing plant physiological disorders, and elevating the build-up of sooty mold, and indirectly by transmitting plant viruses. In this study, we evaluated the susceptibility of 20 yellow squash and zucchini (Cucurbita pepo) cultivars to MEAM1, across three growing seasons in the southeastern United States. Weekly sampling of the numbers of MEAM1 adults, nymphs, and eggs were conducted from the fourth week after seed sowing and across 6 weeks during the summer and fall of 2021 and five weeks during the fall of 2022. In general, adult whitefly populations were high during the first week of sampling but decreased as the seasons progressed. The zucchini cultivar 'Black Beauty' harbored the most adults, while 'Green Eclipse Zucchini' was the least attractive zucchini cultivar to the adults in fall 2022. For yellow squash, 'Early Summer' (summer 2021) and 'Amberpic 8455' (summer 2021 and fall 2022) were the cultivars with the highest adult populations, while 'Lioness' (summer 2021) and 'Gourmet Gold Hybrid' (fall 2022) harbored the lowest adult counts. The whitefly egg counts across both vegetables trailed those of adults and peaked in the second week of sampling. The counts of nymphs increased as the seasons progressed, but there was a decline after the second week during fall 2021. For the yellow squash cultivars, 'Gourmet Gold Hybrid', (summer 2021 and fall 2022), 'Lioness', and 'Fortune' (summer 2021) recorded the highest yields. For zucchini, 'Golden Glory' (summer 2021) was the top performer. These results provide valuable information for whitefly management in yellow squash and zucchini based on host plant susceptibility and yield. [ABSTRACT FROM AUTHOR]

Simple Summary: Hybrid rice often has higher yields than comparable inbred varieties. However, hybrids are sometimes more susceptible to insect herbivores. Outbreeding can improve herbivore resistance in hybrids compared to one (a condition called heterosis) or both (called heterobeltiosis) of their parental lines. The frequency of heterosis for resistance has not been assessed under varying soil nitrogen conditions. Nitrogen is predicted to reduce a plant's ability to resist herbivores but increases its ability to compensate for damage, known as tolerance. We examined the resistance and tolerance of eight hybrids and their parental lines to herbivores by exposing plants to the brown planthopper, whitebacked planthopper or yellow stemborer and observing herbivore fitness responses (i.e., resistance) and herbivore-induced changes to plant biomass (i.e., tolerance). There were no consistent trends in relative resistance or tolerance to the herbivores across plant types; however, improved resistance and tolerance were frequently associated with the male parent. Nitrogen reduced resistance and generally increased tolerance to herbivores irrespective of plant type. Across the eight hybrids, relative resistance and relative tolerance were not determined by heterosis or heterobeltiosis. Our results highlight the difficulties in predicting the outcomes of crossing to achieve relatively resistant hybrids. Hybrid rice results from crossing a male-sterile line (the A line) with a pollen doner (the restorer or R line). In 3-line hybrid breeding systems, a fertile B line is also required to maintain A line populations. Heterosis is defined as a condition of traits whereby the hybrid exceeds the average of the parental lines. Heterobeltiosis is where the hybrid exceeds both parents. Hybrid rice may display heterosis/heterobeltiosis for growth, yield and resistance to herbivores, among other traits. In a greenhouse experiment, we assessed the frequency of heterosis for resistance to the brown planthopper (Nilaparvata lugans (BPH)), whitebacked planthopper (Sogatella furcifera (WBPH)) and yellow stemborer (Scirpophaga incertulas (YSB)) in eight hybrids under varying soil nitrogen conditions. We also assessed plant biomass losses due to herbivore feeding as an approximation of tolerance (the plant's capacity to compensate for damage). Nitrogen reduced resistance to all three herbivores but was also associated with tolerance to WBPH and YSB based on improved plant survival, growth and/or yields. Plant biomass losses per unit weight of WBPH also declined under high nitrogen conditions for a number of hybrids, and there were several cases of overcompensation in rice for attacks by this herbivore. There was one case of nitrogen-related tolerance to BPH (increased grain yield) for a hybrid line with relatively high resistance, likely due to quantitative traits. Heterosis and heterobeltiosis were not essential to produce relatively high herbivore resistance or tolerance across hybrids. [ABSTRACT FROM AUTHOR]

Aphid genomic resources enable the study of complex life history traits and provide information on vector biology, host adaption and speciation. The currant–lettuce aphid (Nasonovia ribisnigri(Hemiptera: Aphididae) (Mosley)) is a cosmopolitan pest of outdoor lettuce (Lactuca sativa (Asterales: Asteraceae) (Linnaeus)). Until recently, the use of resistant cultivars was an effective method for managing N. ribisnigri. A resistant cultivar containing a single gene (Nr‐locus), introduced in the 1980s, conferred complete resistance to feeding. Overreliance of this Nr‐locus in lettuce resulted in N. ribisnigri's ability to break resistance mechanism, with first reports during 2003. Our work attempts to understand which candidate gene(s) are associated with this resistance‐breaking mechanism. We present two de novo draft assembles for N. ribisnigri genomes, corresponding to both avirulent (Nr‐locus susceptible) and virulent (Nr‐locus resistant) biotypes. Changes in gene expression of the two N. ribisnigri biotypes were investigated using transcriptomic analyses of RNA‐sequencing (RNA‐seq) data to understand the potential mechanisms of resistance to the Nr‐locus in lettuce. The draft genome assemblies were 94.2% and 91.4% complete for the avirulent and virulent biotypes, respectively. Out of the 18,872 differentially expressed genes, a single gene/locus was identified in N. ribisnigri that was shared between two resistant‐breaking biotypes. This locus was further explored and validated in Real‐Time Quantitative Reverse Transcription PCR (qRT‐PCR) experiments and has predicted localisations in both the cytoplasm and nucleus. This is the first study to provide evidence that a single gene/locus is likely responsible for the ability of N. ribisnigri to overcome the Nr‐locus resistance in the lettuce host. [ABSTRACT FROM AUTHOR]

Field evaluations of 50 local landraces against the paddy yellow stem borer (YSB), Scirpophaga incertulas (Walker), were conducted at the College of Agriculture, Vishweshwaraiah Canal Farm, Mandya, during the kharif season of 2022 and the summer season of 2023. The extent of damage caused by YSB across different genotypes was assessed at 30, 60, and 90 days post-transplanting in both seasons. Using the Standard Evaluation System for Rice (SES) developed by the International Rice Research Institute (IRRI), genotypes were classified into various resistance categories based on their mean percentage of incidence. In both kharif 2022 and summer 2023 evaluations, nine genotypes displayed a resistant reaction (score 1), while 27 genotypes were classified as moderately resistant (score 3). Additionally, ten genotypes were categorized as moderately susceptible (score 5), and four genotypes were deemed susceptible (score 7). Importantly, no genotypes was classified as either highly resistant or highly susceptible in either season. The identification of these resistant and moderately resistant genotypes offers significant potential for incorporation into future breeding programs aimed at enhancing resistance to yellow stem borer.. [ABSTRACT FROM AUTHOR]

Screening of 50 rice genotypes against brown planthopper infestation was conducted in open field conditions over two consecutive years (Kharif 2018-19 and 2019-20). Based on pest population per hill, rice genotypes IR82475-110-2-2-1-2, Akshyadhan, and MTU-1010 had the least brown planthoppers. TN1, Swarna, MTU 7029, Rajendra Kasturi, Baranideep, and Sahbhagidhan had the highest population and were classified as pest-prone. Rice leaf biochemical characteristics examined in selected genotypes, revealed that the pest population was significantly and positively correlated with total sugar (r = 0.608), crude protein (r = 0.306) and total free amino acid (r = 0.358), but significantly negatively correlated with phenol (r = -0.429), crude silica (r = -0.401), and tannin (r = -0.301). Correlation analysis revealed that susceptible entries contained more total sugar, crude protein, and total free amino acids, whereas resistant genotypes contained significantly more phenol, crude silica, and tannins. This study highlighted the significance of antixenotic properties in rice genotypes against brown planthoppers. [ABSTRACT FROM AUTHOR]

BACKGROUND: The wheat stem sawfly (WSS, Cephus cinctus) is a major pest of wheat (Triticum aestivum) and can cause significant yield losses. WSS damage results from stem boring and/or cutting, leading to the lodging of wheat plants. Although solid‐stem wheat genotypes can effectively reduce larval survival, they may have lower yields than hollow‐stem genotypes and show inconsistent solidness expression. Because of limited resistance sources to WSS, evaluating diverse wheat germplasm for novel resistance genes is crucial. We evaluated 91 accessions across five wild wheat species (Triticum monococcum, T. urartu, T. turgidum, T. timopheevii, and Aegilops tauschii) and common wheat cultivars (T. aestivum) for antixenosis (host selection) and antibiosis (host suitability) to WSS. Host selection was measured as the number of eggs after adult oviposition, and host suitability was determined by examining the presence or absence of larval infestation within the stem. The plants were grown in the greenhouse and brought to the field for WSS infestation. In addition, a phylogenetic analysis was performed to determine the relationship between the WSS traits and phylogenetic clustering. RESULTS: Overall, Ae. tauschii, T. turgidum and T. urartu had lower egg counts and larval infestation than T. monococcum, and T. timopheevii. T. monococcum, T. timopheevii, T. turgidum, and T. urartu had lower larval weights compared with T. aestivum. CONCLUSION: This study shows that wild relatives of wheat could be a valuable source of alleles for enhancing resistance to WSS and identifies specific germplasm resources that may be useful for breeding. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

IntroductionThe cowpea weevil, Callosobruchus maculatus Fab., is the most economically important storage pest of cowpeas, causing up to 100 percent grain losses within six months of storage. To sustainably resist weevil damage, the cowpea cultivar IT86D-1010 was genetically modified via Agrobacterium-mediated transformation to produce event CSI-32, which expresses the kidney bean alpha-amylase inhibitor 1 (αAI-1) protein exclusively in the seed, providing suppression of weevil development.MethodsTrials were conducted in Ghana and Nigeria during the 2023 growing season to assess the performance in the field and in post-harvest storage of this transgenic event (CSI-32) and of four check lines: the non-transformed parental line (IT86D-1010) and three released varieties (SAMPEA 7, SAMPEA 20-T and IT13K-1070-2). Data collected from the field trials comprised plant growth parameters, pest infestations and damage, and grain yield. Harvested grain from each replicated entry was used in a storage assessment of bruchid resistance following artificial infestation with laboratory-reared cowpea weevils. Data were collected on egg oviposition, adult emergence, and grain damage as well as computation of median development period and Dobie’s susceptibility index for each entry.Results and discussionThe agronomic performance and phenotypic characteristics of event CSI-32 were very similar to its parental counterpart and the other compared varieties. However, event CSI-32 exhibited complete suppression of weevil emergence and resistance to seed damage over the four-month period of the post-harvest study.ConclusionsThis work represents the first field study of genetically modified cowpea expressing the αAI-1 protein. It demonstrates how a biotechnology solution to mitigate significant economic losses during cowpea storage, offers great potential for cowpea improvement programs.

Abstract Background The sweet potato whitefly (Bemisia tabaci) is a globally important insect pest that damages crops through direct feeding and by transmitting viruses. Current B. tabaci management revolves around the use of insecticides, which are economically and environmentally costly. Host plant resistance is a sustainable option to reduce the impact of whiteflies, but progress in deploying resistance in crops has been slow. A major obstacle is the high cost and low throughput of screening plants for B. tabaci resistance. Oviposition rate is a popular metric for host plant resistance to B. tabaci because it does not require tracking insect development through the entire life cycle, but accurate quantification is still limited by difficulties in observing B. tabaci eggs, which are microscopic and translucent. The goal of our study was to improve quantification of B. tabaci eggs on several important crop species: cassava, cowpea, melon, sweet potato and tomato. Results We tested a selective staining process originally developed for leafhopper eggs: submerging the leaves in McBryde’s stain (acetic acid, ethanol, 0.2% aqueous acid Fuchsin, water; 20:19:2:1) for three days, followed by clearing under heat and pressure for 15 min in clearing solution (LGW; lactic acid, glycerol, water; 17:20:23). With a less experienced individual counting the eggs, B. tabaci egg counts increased after staining across all five crops. With a more experienced counter, egg counts increased after staining on melons, tomatoes, and cowpeas. For all five crops, there was significantly greater agreement on egg counts across the two counting individuals after the staining process. The staining method worked particularly well on melon, where egg counts universally increased after staining for both counting individuals. Conclusions Selective staining aids visualization of B. tabaci eggs across multiple crop plants, particularly species where leaf morphological features obscure eggs, such as melons and tomatoes. This method is broadly applicable to research questions requiring accurate quantification of B. tabaci eggs, including phenotyping for B. tabaci resistance.

Abstract Africa accounts for a significant portion of the world’s sweetpotato production where it is widely grown as a staple crop. In sub-Saharan Africa (SSA), sweetpotato serves as an important year-round source of calories and nutrition, a form of income for smallholder and pre-commercial farmers, and is increasingly used as silage for animal feed. However, yield per hectare is considerably lower in SSA than from other regions primarily due to sweetpotato weevils (SPW, Cylas spp., Coleoptera: Brentidae). Weevil feeding causes physical damage to the root and can induce chemical responses that give the storage root a bitter taste, both of which make them unmarketable. Commercial growers in many developed countries rely on frequent chemical treatments and strict quarantine regulations to control SPW, however, this approach is currently not practical for many areas of SSA. In this paper we, (1) outline factors that contribute to SPW infestation; (2) review available strategies and ongoing research for control of SPW, including chemical pesticides, biological control (macro-organismal as well as microbial control), cultural practices, selective breeding, and biotechnology; and (3) discuss the potential for implementing an integrated pest management (IPM) approach that leverages a combination of techniques. We rationalize that a multifaceted strategy for SPW control will improve both the quantity and quality of sweetpotato production in Africa.

Maize (Zea mays L.) is an important crop worldwide. In the southern area of the United States the two major pests of maize are fall armyworm (Spodoptera frugiperda (J.E. Smith)) and corn earworm (Helicoverpa zea (Boddie)). Fall armyworm primarily attacks maize leaves and corn earworm damages the upper part of the ear. An effort to obtain new sources for resistance is conducted through Germplasm Enhancement of Maize (GEM) project. Plants were infested at the whorl growth stage with fall armyworm neonates and evaluated for leaf-feeding damage 14 days after infestation. Plants were evaluated for ear-feeding damage based on natural infestation by corn earworm. Leaf-feeding damage values in Tifton were lower than at Mississippi State. GEMN-0259, GEMS-0311, and GEMS-0312 exhibited similar resistance levels with the resistant check on leaf-feeding damage in Tifton. Ear-feeding ratings in Tifton and Mississippi State were similar. GEMS-0311 showed the most resistance to ear-feeding damage in both environments. GEMS-0311 with resistance to both insects could be used for new germplasm development. [ABSTRACT FROM AUTHOR]

Allium species are known for their culinary, medicinal, and ornamental purposes. Fusarium basal rot is one of the most damaging soilborne fungal diseases of Allium species and poses a significant threat to yield, quality, and storage life worldwide. Various species of Fusarium have been identified as causal agents for Fusarium basal rot, depending on the Allium species involved. Diverse disease management practices have been implemented to mitigate the impact of Fusarium basal rot. This review article provides a comprehensive overview of the recent progress in detecting different species of Fusarium involved in Fusarium basal rot and strategies to control them in affected Allium species involving chemical, biological, and cultural methods. It covers the latest advancements in host plant resistance research from traditional breeding to modern molecular techniques and studying secondary metabolites involved in defense mechanisms against Fusarium basal rot. [ABSTRACT FROM AUTHOR]

Sesame, an oilseed plant with multiple applications, is susceptible to infestations by the stink bug Nezara viridula (Linnaeus, 1758) (Hemiptera: Pentatomidae). This pest suctions the seeds of this plant and injects toxins into them. Possible sources of resistance on sesame cultivars are important to manage this bug. The objective of this study was to evaluate the biological aspects of N. viridula fed on three sesame cultivars aiming to select possible resistance sources for integrated pest management (IPM) programs of this stinkbug. The experimental design used randomized blocks with three treatments and four replications, each with newly emerged N. viridula nymphs fed with sesame capsules of the cultivars BRS Anahí (T1), BRS Morena (T2) and BRS Seda (T3). Two to three green sesame capsules were supplied every two days per group of ten N. viridula nymphs as one replication until the beginning of the adult stage. Adults of this stinkbug were fed in the same manner as its nymphs but with mature sesame capsules until the end of the observations. Survival during each of the five instars and of the nymph stage of N. viridula with green sesame capsules was similar between cultivars, but the duration of the nymph stage was shorter with green capsules of the BRS Morena than with those of the BRS Anahí. The oviposition period, number of egg masses and eggs per female, and the percentage of nymphs hatched were higher with mature capsules of the sesame cultivar BRS Anahí and lower with the others. Nymphs did not hatch from eggs deposited by females fed mature seed capsules of the sesame cultivar BRS Morena, which may indicate a source of resistance against this stinkbug in this cultivar. The worldwide importance of N. viridula to sesame cultivation makes these results useful for breeding programs of this plant aiming to develop genotypes resistant to this bug. In addition, the BRS Morena is a cultivar already commercially available and can be recommended in places where there is a history of incidence of N. viridula, aiming to manage the populations of this pest. [ABSTRACT FROM AUTHOR]

The cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a major insect pest of various agricultural crops worldwide. In this study, the effects of eight sorghum [Sorghum bicolor (L.) Moench, Poaceae] cultivars (Payam, Pegah, Sepideh, Spidfid, Kimia, KGS23, KFS2, and KFS18) on life table parameters, feeding performance, and activities of digestive enzymes in H. armigera were assessed under laboratory conditions. The insects were fed grains of the eight cultivars. Furthermore, the phytochemicals starch, proteins, flavonoids, and phenolic compounds in the grains were quantified to investigate their relationship with ecological and physiological parameters in H. armigera. Our results revealed that H. armigera had the shortest development time when reared on cv. Sepideh and the longest development time when reared on cv. Payam. The insects reached the highest and lowest intrinsic rate of increase (r) on cv. Sepideh and Payam, respectively. The relative growth rate (RGR) and efficiency of conversion of digested food (ECD) of larvae were highest and lowest on cv. Sepideh and Payam, respectively. Larval proteolytic activity was highest on cv. KFS18 and lowest on cv. Sepideh. Concerning phytochemicals, protein content was highest in cv. KFS18 and lowest in cv. Payam and KGS 23. Total phenolic levels were highest in cv. Payam and lowest in cv. Sepideh. According to the correlation analysis, overall, plant protein content was negatively correlated with insect development time, but positively correlated with pupal weight and r. Total phenolic content was positively correlated with insect development time, and negatively correlated with r and RGR. Cluster analysis indicated that cv. Sepideh was the most susceptible host, whereas cv. Payam was the most resistant. Therefore, cv. Payam may be a candidate for use in integrated pest management (IPM) against H. armigera. [ABSTRACT FROM AUTHOR]

Maruca vitrata (Fabricius) (Lepidoptera: Crambidae) is a serious threat to grain legumes, particularly pigeonpea. Varietal resistance in pigeonpea against M. vitrata and knowledge about the seasonal abundance of the pest are crucial to manage it efficiently. Nine pigeonpea genotypes (AL 1932, AL 2000, AL 1747, MN 1, AL 2102, PADT16, AL 201, PAU 881 and AL 882) were screened against M. vitrata under field conditions for two years (Kharif 2020 and 2021). M. vitrata larvae were first observed during the 36th SMW (Standard Meteorological Week) in the early flowering genotypes (MN 1 and PADT 16). The pest population gradually reached its peak during the 40th SMW on all the genotypes and gradually declined thereafter, with no pest population after the 43rd SMW. Mean larval population, web counts and per cent pod damage were the lowest in genotype AL 1747 and the highest in genotype MN 1. The number of larvae and webs per plant had a non-significant correlation with all the weather parameters. Principal component analysis (PCA) was used and the variables were transformed into principal components (PC) to explain the nature and extent of the relationships among different variables. During kharif 2020, PC1 and PC2 between M. vitrata larvae, webs and weather parameters captured 53.0 and 34.9 per cent of the variability in data, respectively whereas during kharif 2021, PC1 and PC2 captured 49.0 and 35.8 per cent of the variability in data, respectively. Our results show that genotype AL 1747 consistently performed better under M. vitrata infestation and therefore, it can be used in future breeding programmes to develop resistant varieties against M. vitrata. [ABSTRACT FROM AUTHOR]

The tomato leaf curl viruses (ToLCVs) causing tomato leaf curl disease (ToLCD) in tomatoes is one of the significant constraints for tomato production worldwide and is transmitted by the whitefly, Bemisia tabaci. The ToLCVs, with the emergence of several recombinant variants and B. tabaci with changes in its capability in pathogen transmission, are reported all over the Indian subcontinent. Tomato genotypes resistant to B. tabaci and ToLCV are vital for sustainable control of ToLCD. In the current study, the level of resistance/susceptibility of tomato genotypes to B. tabaci and ToLCV incidence under greenhouse conditions were studied, and promising entries were assessed for antixenosis (non-preference) and antibiosis resistance against B. tabaci. Greenhouse screening by mass release of ToLCV-virulent whiteflies revealed that genotypes EC-520,078 and EC-620,389 (p = < 0.0001) recorded highly resistant reactions for whitefly infestation and ToLCV incidence. The adult settling assay revealed that the genotypes EC-520,078, EC-620,389, EC-315,477, and EC-620,401 (p = < 0.0001) were less preferred by whiteflies. Tests on fecundity, nymphal emergence, nymphal development, and population buildup were conducted to infer the antibiosis effect of the tomato genotypes against B. tabaci. The genotype EC-520,078 (p = < 0.0001) recorded the lowest number of eggs, EC-620,389 (p = < 0.0001) with the lowest nymphal emergence, and EC-520,078, EC-620,389, and EC-620,401 (p = < 0.0001) registered the lowest nymphal development. The F2 generation in the population buildup study was significantly lower in EC-520,078, followed by EC-620,389 and EC-631,364 (p = < 0.0001). The identified resistant sources could be used to develop resistant genotypes against whiteflies and ToLCV in tomatoes. [ABSTRACT FROM AUTHOR]

Anticarsia gemmatalis (Lepidoptera: Erebidae) is distributed in tropical and subtropical regions of America, and is an important pest of Fabaceae, such as: soybean, peanut, common bean, cowpea, pea, chickpea and kudzu. In soybean, the velvet bean caterpillar is important due to the plant defoliation in their larval stage. This study evaluated soybean cultivars as source of resistance to A. gemmatalis by antixenosis (attractiveness and non-preference for feeding) and antibiosis (biological parameters of the insect). The parameters evaluated were: antixenosis: attractiveness and non-preference, dry mass consumed and attractiveness index and antibiosis: duration of larval and pupal stages, adult longevity, total cycle, larval and pupal weights and larval, pupal and total viability. Considering antixenosis and antibiosis the least suitable cultivars for A. gemmatalis were found to be BRS 8383 IPRO, BRS 1074 IPRO, BRS 1061 IPRO, BRS 7180 IPRO, BRS 9383 IPRO, BRS 8980 IPRO and BRS 1003 IPRO due to high mortality in the larval phase. The cultivars BRS 523 and BRS 543 RR “block technology” suggest displays antixenosis and or antibiosis to A. gemmatalis. These cultivars can be used by soybean producers in combination with other control tactics in soybean IPM. [ABSTRACT FROM AUTHOR]