Asian Corn Borer Ostrinia Furnacalis Research Articles

Toxic Effects of Bt-(Cry1Ab+Vip3Aa) Maize (“DBN3601T’’ Event) on the Asian Corn Borer Ostrinia furnacalis (Guenée) in Southwestern China

Asian corn borer (ACB), Ostrinia furnacalis, is an important agricultural pest affecting maize production in southwestern China, but knowledge of the toxic effect of Bt maize on the pest has been insufficient until now. In this study, we determined the susceptibility of ACB to Cry1Ab, Vip3Aa, and their complex proteins and evaluated the efficacy of Chinese domestic Bt-(Cry1Ab+Vip3Aa) maize (“DBN3601T” event) against the pest in Yunnan Province of southwestern China. The susceptible bioassay indicated that the LC50 values of the Cry1Ab and Cry1Ab+Vip3Aa proteins expressed by the Bt maize varieties against ACB larvae were 51.42 and 46.85 ng/g, respectively; however, the ACB larva was insensitive to the Vip3Aa protein. The Cry1Ab+Vip3Aa protein contents in V6–V8 leaves, VT tassels, R1 silks, R2 kernels, R3 stalks and R3 cobs of the Bt-(Cry1Ab+Vip3Aa) maize were 114.20, 30.69, 3.77, 8.92, 11.09 and 10.99 μg/g, respectively. The larval feeding test indicated that the Bt-(Cry1Ab+Vip3Aa) maize was more toxic to the early instar larvae, and the survival time of larvae fed on the leaves was the shortest, while it survived the longest on stalks. The identification of maize resistance levels in the field showed that both larval density and plant damage score of Bt-(Cry1Ab+Vip3Aa) maize were significantly lower than those in conventional maize. It is concluded that the Bt-(Cry1Ab+Vip3Aa) maize can be used for control of the ACB in southwestern China.

Growth and yield of maize in response to reduced fertilizer application and its impacts on population dynamics and community biodiversity of insects and soil microbes

In the North China Plain, farmers are using excessive amounts of fertilizer for the production of high-yield crop yield, which indirectly causes pollution in agricultural production. To investigate an optimal rate of fertilizer application for summer maize, the fertilizer reduction experiments with 600 kg/ha NPK (N: P2O5: K2O = 28: 8: 10) as normal fertilizer application (NFA), (i.e., 100F), were conducted successively during 2020 and 2021 to study the effects of reduced fertilizer rates, including 90% (540 kg/ha; i.e., 90F), 80% (480 kg/ha; i.e., 80F), 62.5% (375 kg/ha; i.e., 62.5F) and 50% (300 kg/ha; i.e., 50F) of NFA, on the plant growth of maize, the dynamics of key population abundances and community diversity of insects, and the composition and diversity of microbial community and finally to find out the N-metabolic enzymes’ activity in soil. Our findings revealed that the fertilizer reduction rates by 10% - 20% compared to the current 100% NFA, and it has not significantly affected the plant growth of maize, not only plant growth indexes but also foliar contents of nutrients, secondary metabolites, and N-metabolic enzymes’ activity. Further, there was no significant alteration of the key population dynamics of the Asian corn borer (Ostrinia furnacalis) and the community diversity of insects on maize plants. It is interesting to note that the level of N-metabolic enzymes’ activity and microbial community diversity in soil were also not affected. While the fertilizer reduction rate by 50% unequivocally reduced field corn yield compared to 100% NFA, significantly decreased the yield by 17.10%. The optimal fertilizer application was calculated as 547 kg/ha (i.e., 91.17% NFA) based on the simulation analysis of maize yields among the five fertilizer application treatments, and the fertilizer application reduced down to 486 kg/ha (i.e., 81.00% NFA) with a significant reduction of maize yield. These results indicated that reduced the fertilizer application by 8.83% - 19.00% is safe and feasible to mitigate pollution and promote sustainable production of maize crops in the region.

Tripartite interactions of an endophytic entomopathogenic fungus, Asian corn borer, and host maize under elevated carbon dioxide.

Biological control of insect pests is encountering an unprecedented challenge in agricultural systems due to the ongoing rise in carbon dioxide (CO2) level. The use of entomopathogenic fungi (EPF) in these systems is gaining increased attention, and EPF as crop endophytes hold the potential for combining insect pest control and yield enhancement of crops, but the effects of increased CO2 concentration on this interaction are poorly understood. Here, the introduction of endophytic EPF was explored as an alternative sustainable management strategy benefiting crops under elevated CO2, using maize (Zea mays), Asian corn borer (Ostrinia furnacalis), and EPF (Beauveria bassiana) to test changes in damage to maize plants from O. furnacalis, and the nutritional status (content of carbon, nitrogen, phosphorus, potassium), biomass, and yield of maize. The results showed that endophytic B. bassiana could alleviate the damage caused by O. furnacalis larvae for maize plants under ambient CO2 concentration, and this effect was enhanced under higher CO2 concentration. Inoculation with B. bassiana effectively counteracted the adverse impact of elevated CO2 on maize plants by preserving the nitrogen content at its baseline level (comparable with ambient CO2 conditions without B. bassiana). Both simultaneous effects could explain the improvement of biomass and yield of maize under B. bassiana inoculation and elevated CO2. This finding provides key information about the multifaceted benefits of B. bassiana as a maize endophyte. Our results highlight the promising potential of incorporating EPF as endophytes into integrated pest management strategies, particularly under elevated CO2 concentrations. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Genome-wide profiles of H3K9me3, H3K27me3 modifications, and DNA methylation during diapause of Asian corn borer (Ostrinia furnacalis).

Diapause represents a crucial adaptive strategy used by insects to cope with changing environmental conditions. In North China, the Asian corn borer (Ostrinia furnacalis) enters a winter larval diapause stage. Although there is growing evidence implicating epigenetic mechanisms in diapause regulation, it remains unclear whether dynamic genome-wide profiles of epigenetic modifications exist during this process. By investigating multiple histone modifications, we have discovered the essential roles of H3K9me3 and H3K27me3 during diapause of the Asian corn borer. Building upon previous findings in vertebrates highlighting the connection between DNA methylation and repressive histone methylations, we have examined changes in the genome-wide profile of H3K9me3, H3K27me3, and DNA methylation at the nondiapause, prediapause, and diapause stages. Data analysis reveals significant alterations in these three modifications during diapause. Moreover, we observe a correlation between the H3K9me3 and H3K27me3 modification sites during diapause, whereas DNA modifications show little association with either H3K9me3 or H3K27me3. Integrative analysis of epigenome and expression data unveils the relationship between these epigenetic modifications and gene expression levels at corresponding diapause stages. Furthermore, by studying the function of histone modifications on genes known to be important in diapause, especially those involved in the juvenile pathway, we discover that the juvenile hormone pathway lies downstream from H3K9me3 and H3K27me3 histone modifications. Finally, the analysis of gene loci with modified modifications unreported in diapause uncovers novel pathways potentially crucial in diapause regulation. This study provides a valuable resource for future investigations aiming to elucidate the underlying mechanisms of diapause.

Salicylic acid inducing the expression of maize anti-insect gene SPI: a potential control strategy for Ostrinia furnacalis

BackgroundDue to being rooted in the ground, maize (Zea mays L.) is unable to actively escape the attacks of herbivorous insects such as the Asian corn borer (Ostrinia furnacalis). In contrast to the passive damage, plants have evolved defense mechanisms to protect themselves from herbivores. Salicylic acid, a widely present endogenous hormone in plants, has been found to play an important role in inducing plant resistance to insects. In this study, we screened and identified the insect resistance gene SPI, which is simultaneously induced by SA and O. furnacalis feeding, through preliminary transcriptome data analysis. The functional validation of SPI was carried out using bioinformatics, RT-qPCR, and heterologous expression protein feeding assays.ResultsBoth SA and O. furnacalis treatment increased the expression abundance of SA-synthesis pathway genes and SPI in three maize strains, and the upregulation of SPI was observed strongly at 6 hours post-treatment. The expression of SPI showed a temporal relationship with SA pathway genes, indicating that SPI is a downstream defense gene regulated by SA. Protein feeding assays using two different expression vectors demonstrated that the variation in SPI protein activity among different strains is mainly due to protein modifications.ConclusionsOur research results indicate that SPI, as a downstream defense gene regulated by SA, is induced by SA and participates in maize's insect resistance. The differential expression levels of SPI gene and protein modifications among different maize strains are one of the reasons for the variation in insect resistance. This study provides new insights into ecological pest control in maize and valuable insights into plant responses to SA-induced insect resistance.

Novel Butenolide Derivatives as Dual-Chitinase Inhibitors to Arrest the Growth and Development of the Asian Corn Borer.

OfChtI and OfChi-h are considered potential targets for the control of Asian corn borer (Ostrinia furnacalis). In this work, the previously reported OfChtI inhibitor 5f was found to show certain inhibitory activity against OfChi-h (Ki = 5.81 μM). Two series of novel butenolide derivatives based on lead compound 5f were designed with the conjugate skeleton, contributing to the π-binding interaction to chitinase, and then synthesized. Compounds 4a-l and 7a-p displayed excellent inhibitory activities against OfChtI and OfChi-h, respectively, at a concentration of 10 μM. Compound 4h was found to be a good dual-Chitinase inhibitor, with Ki values of 1.82 and 2.00 μM against OfChtI and OfChi-h, respectively. The inhibitory mechanism studies by molecular docking suggested that π-π stacking interactions were crucial to the inhibitory activity of novel butenolide derivatives against two different chitinases. A preliminary bioassay indicated that 4h exhibited certain growth inhibition effects against O. furnacalis. Butenolide-like analogues should be further studied as promising novel dual-chitinase inhibitor candidates for the control of O. furnacalis.

Resistance Mechanism Exhibited by Selected Maize Varieties to Asian Corn Borer Ostrinia furnacalis Guenee (Lepidoptera: Crambidae), Philippines

Resistance Mechanism Exhibited by Selected Maize Varieties to Asian Corn Borer Ostrinia furnacalis Guenee (Lepidoptera: Crambidae), Philippines

A dual-subcellular localized β-glucosidase confers pathogen and insect resistance without a yield penalty in maize.

Maize is one of the most important crops for food, cattle feed and energy production. However, maize is frequently attacked by various pathogens and pests, which pose a significant threat to maize yield and quality. Identification of quantitative trait loci and genes for resistance to pests will provide the basis for resistance breeding in maize. Here, a β-glucosidase ZmBGLU17 was identified as a resistance gene against Pythium aphanidermatum, one of the causal agents of corn stalk rot, by genome-wide association analysis. Genetic analysis showed that both structural variations at the promoter and a single nucleotide polymorphism at the fifth intron distinguish the two ZmBGLU17 alleles. The causative polymorphism near the GT-AG splice site activates cryptic alternative splicing and intron retention of ZmBGLU17 mRNA, leading to the downregulation of functional ZmBGLU17 transcripts. ZmBGLU17 localizes in both the extracellular matrix and vacuole and contribute to the accumulation of two defence metabolites lignin and DIMBOA. Silencing of ZmBGLU17 reduces maize resistance against P.aphanidermatum, while overexpression significantly enhances resistance of maize against both the oomycete pathogen P. aphanidermatum and the Asian corn borer Ostrinia furnacalis. Notably, ZmBGLU17 overexpression lines exhibited normal growth and yield phenotype in the field. Taken together, our findings reveal that the apoplastic and vacuolar localized ZmBGLU17 confers resistance to both pathogens and insect pests in maize without a yield penalty, by fine-tuning the accumulation of lignin and DIMBOA.

Corn specimens resistant to Asian corn borer in the Primorsky Territory

Sixty-five samples of ecological corn nursery were studied to determine their resistance to the Asian corn borer (Ostrinia furnacalis Guenee) on the natural background of pest infestation for selection for entoimmunity and production purposes. The experiment was conducted in 2019–2021 in the conditions of the Primorsky Territory. Three components of pest resistance of corn samples were studied. As a result of the research, 30 corn hybrids were singled out as less damaged (marked by stalk resistance). Characterization of the most resistant of them (by total damage score) is given. According to the attractiveness of the corn plants for egg-laying female moths, there were 2 hybrids with the lowest pest colonization (10%). Hybrids Newton and P 9300 were noted as less attractive. Twelve corn accessions were characterized by tolerance to pest damage (with insignificant stem and cob stem breakage). Of these, hybrids LK-0.5 and P 9300 were the most tolerant. As a result of research, promising varieties and hybrids of domestic selection NUR, Ladozhsky 301 AMV, Ladozhsky 410 MV, Newton, Baikal were identified. These hybrids of ecological corn nursery are characterized not only by resistance to pest damage, but also to other biotic and abiotic stresses in the conditions of Primorsky Territory. Yields of the selected hybrids varied from 4.2 to 7.4 t/ha, the released variety Slavyanka – on average 5.5 t/ha. The standard corn variety Slavyanka was noted as tolerant. According to the degree of damage, it belongs to the group of medium resistant samples. Resistant corn hybrids made up the group of early-ripening and middle-early specimens.

Baseline Susceptibility of the Field Populations of Ostrinia furnacalis in Indonesia to the Proteins Cry1A.105 and Cry2Ab2 of Bacillus thuringiensis.

Genetically modified MON 89034 corn (Zea mays L.) expressing Bacillus thuringiensis (Bt) insecticidal proteins, viz. Cry1A.105 and Cry2Ab2, is a biotechnological option being considered for the management of the major corn pest in Indonesia, the Asian corn borer (Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae)). As a part of a proactive resistance-management program for MON 89034 corn in Indonesia, we assessed the baseline susceptibility of field-collected populations of O. furnacalis to Cry1A.105 and Cry2Ab2 proteins. Dose-response bioassays using the diet-dipping method indicated that the lethal concentration (LC50) values of Cry1A.105 and Cry2Ab2 in 24 different field populations of O. furnacalis ranged from 0.006 to 0.401 µg/mL and from 0.044 to 4.490 µg/mL, respectively, while the LC95 values ranged from 0.069 to 15.233 µg/mL for Cry1A.105 and from 3.320 to 277.584 µg/mL for Cry2Ab2. The relative resistance ratios comparing the most tolerant field populations and an unselected laboratory population were 6.0 for Cry1A.105 and 2.0 for Cry2Ab2 based on their LC50 values. Some field populations were more susceptible to both proteins than the unselected laboratory population. The LC99 and its 95% fiducial limits across the field populations were calculated and proposed as candidate diagnostic concentrations. These data provide a basis for resistance monitoring in Bt Corn and further support building resistance-management strategies in Indonesia.

Larval competition analysis and its effect on growth of Ostrinia furnacalis (Lepidoptera: Crambidae) at natural conditions in Northeast China.

The Asian corn borer (Ostrinia furnacalis, Lepidoptera, Crambidae) and Oriental armyworm (Mythimna separata, Lepidoptera, Noctuidae) are 2 major lepidopteran pests of the maize plant, especially the whorls and tassels. The aim of this study was to investigate competition between 2 lepidopteran pests of maize. Intraspecific and interspecific competition occurs when O. furnacalis and M. separata larvae interact with various stages of the maize plant. Therefore, determining whether this competition can decrease larval damage by causing adverse effects on larval growth is crucial. During the maize growing season of 2022, the interaction of these species was assessed in the experimental field of Jilin Agricultural University, China. Interspecific and intraspecific competition of larvae in different maize tissues and the influence of competition on larval development was determined in the fields. The results showed that first, probing behavior was significantly frequent in O. furnacalis larvae; intraspecific and interspecific attack was significant at 4th instar (with leaf, silk, and kernel). Interspecific defense behavior was significant at 3rd instar (without food). O. furnacalis larvae showed attack behavior toward M. separata larvae frequently. Second, competition increased the mortality rate of O. furnacalis larvae (intraspecific, 67%; interspecific, 33%) and decreased pupation emergence rate. Thus, intraspecific and interspecific competition might affect the competitive displacement of pest species sharing the same ecological niche, as well as the prevalence and population dynamics of pests, and help to develop integrated pest management strategies.

Transcriptome analysis of immune-related genes of Asian corn borer (Ostrinia furnacalis [Guenée]) after oral bacterial infection.

The Asian corn borer (Ostrinia furnacalis) is an important agricultural pest causing serious damage to economic crops, such as corn and sorghum. The gut is the first line of defense against pathogens that enter through the mouth. Staphylococcus aureus was used to infect the O. furnacalis midgut to understand the midgut immune mechanism against exogenous pathogens to provide new ideas and methods for the prevention and control of O. furnacalis. A sequencing platform was used for genome assembly and gene expression. The unigene sequences were annotated and functionally classified by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Significant differences were found in the induced expression profiles before and after infection. Some differentially expressed genes have important relations with lipid metabolism and immune mechanism, suggesting that they play an important role in the innate immune response of O. furnacalis. Furthermore, quantitative real-time polymerase chain reaction assay was used to identify the key genes involved in the signaling pathway, and the expression patterns of these key genes were confirmed. The results could help study the innate immune system of lepidopteran insects and provide theoretical support for the control of related pests and the protection of beneficial insects.

Asian Corn Borer (Ostrinia furnacalis) Infestation Increases Fusarium verticillioides Infection and Fumonisin Contamination in Maize and Reduces the Yield.

Field trials based on manual infestation of the Asian corn borer (ACB) (Ostrinia furnacalis [Guenée]) and Fusarium verticillioides (Nirenberg) atomization were conducted on four maize hybrids to investigate the relationship between ACB infestation and F. verticillioides infection, yield loss, and fumonisin contamination in maize. Analysis of fumonisins B1 and B2 was carried out using an LC-MS/MS system. In this study, manual ACB infestation significantly promoted F. verticillioides infection (both symptomatic and symptomless) and grain fumonisin levels. Ear rot incidence and severity, symptomless kernel infection, and fumonisin contamination were significantly correlated to each other and to ACB damage severity. Manual ACB infestation increased fumonisin levels from 580 to 4,418 µg/kg in 2018; 6,059 to 10,681 µg/kg in 2019 spring-sown maize (2019A); and 2,042 to 5,060 µg/kg in 2019 summer-sown maize (2019B), with the threshold of the European Union (EU) being 4,000 µg/kg. The threshold was exceeded in spring of 2019 in untreated controls. Regarding yield, significant negative correlation between ACB damage and ear weight was observed in three seasons. These results indicated that ACB infestation can lead to severe quality degradation and yield loss of maize. Kernel fumonisin levels may exceed the concentration threshold of the EU in certain conditions, threatening the health of livestock and humans. Measures should be taken to reduce ACB infestation to ensure food and feed security.

Identification and gene expression analysis of serine proteases and their homologs in the Asian corn borer Ostrinia furnacalis

Serine proteases (SPs) and their homologs (SPHs) are among the best-characterized gene families. They are involved in several physiological processes, including digestion, embryonic development and immunity. In the current study, a total of 177 SPs-related genes were characterized in the genome of Ostrinia furnacalis. The activation site of SPs/SPHs and enzyme specificity of SPs were identified, and the findings showed that most of the SPs analyzed possessed trypsin substrate specificity. Several SPs/SPHs with similar simple gene structures had tandem repeat-like distributions on the scaffold, indicated that gene expansion has occurred in this large family. Furthermore, we constructed 30 RNA sequencing libraries including four with developmental stage and four middle larval stage tissues to study the transcript levels of these genes. Differentially upregulated and downregulated genes were obtained via data analysis. More than one-quarter of the genes were specifically identified as highly expressed in the midgut in compared to the other three tissues evaluated. In the current study, the domain structure, gene location and phylogenetic relationship of genes in O. furnacalis were explored. Orthologous comparisons of SPs/SPHs between model insects and O. furnacalis indicated their possible functions. This information provides a basis for understanding the functional roles of this large family.

Intra-Population Alteration on Voltinism of Asian Corn Borer in Response to Climate Warming.

The Asian corn borer (ACB) Ostrinia furnacalis (Guenée) can occur in one to seven generations annually from cool (48°00' N) to warm (18°10' N) region of corn cultivation in China. Although ACB is commonly known as a facultative larval diapause insect, the co-existence of various voltinism suggests that intra-population variation may have evolved for the nature of diapause, i.e., voltinism plasticity. Here, we conducted recurrent selection efforts to establish three strains of, respectively, univoltine (with obligate diapause), multivoltine (with facultative diapause), and non-diapausing ACB under various temperature and photoperiod environments. The univoltine (Lu) strain has evolved a stable univoltinism under a diapause suppressing condition (16 h daylength at 28 °C), with the diapause incidence constantly over 80% after three generations of selection. The multivoltine strain (Lm) under the high temperature (28 °C) was shown to have a typical facultative diapause induced by a range of short-day lengths (11-13.5 h). Diapause incidence was constantly <2.6% under the long day length (16 h) when the temperature was from 18 to 28 °C, i.e., low temperature could not enhance the diapause response in the Lm strain. However, the development was prolonged from 14.2 ± 0.3 d to 46.0 ± 0.8 d when the temperature was reduced from 28 °C to 18 °C. The majority (94.4%) of the developed Ln strain still maintained the non-diapausing nature under a diapause enhancing condition, i.e., a short (13 h) daylength at a low temperature (22 °C). Lm and Ln were able to complete their second generation in Heihe (50°14' N) if the first-generation moth oviposits before 18 June. The study suggests that ACB has evolutionary intra-population variation in voltinism. Under the climate change scenario warmer spring and summer might affect the proportion of sympatric voltine biotype populations that evolve toward being multivoltine.

Using insecticides for the protection of maize plants against the Asian corn borer

Maize is a global leader among grain crops in terms of planting area. Its uniqueness is related to a high potential yield and versatility. There are a great number of pest species that significantly damage maize plants reducing the yield by 30-50 % sometimes and drastically decreasing grain quality. One of the most dangerous pests in Russia and overseas is the corn borer. The paper presents the research data on five insecticides with the following active ingredients (a.i.): emamectin benzoate (50 g/l), aversectin C (50 g/l), thiacloprid (100 g/l) + deltamethrin (10 g/l), imidacloprid (700 g/l) + alpha-cypermethrin (120 g/l), and lambda-cyhalothrin (50 g/l) + chlorantraniliprole (100 g/l). Maize plants differed in the degree of damage to cobs and stalks depending on the product employed.Our research goal was to study the effectiveness of insecticides against the Asian corn borer (Ostrinia furnacalis Guenee). The research showed that the insecticides containing imidacloprid (700 g/l) + alpha-cypermethrin (120 g/l) and lambda-cyhalothrin (50 g/l) + chlorantraniliprole (100 g/l) were the most effective against the Asian corn borer. No damage to maize ears, peduncles, and stalks was detected if these insecticides were applied. A high percentage of damaged ears and stalks was observed in the control variant (without pesticide application).

Current understandings of olfactory molecular events in the Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae).

The Asian corn borer Ostrinia furnacalis (Lepidoptera: Crambidae) is a serious corn pest with widespread distribution in East Asia. Its olfactory mechanism is a focus of scientific study, aiming to find good ways to control this pest. Molecular events are considered to be important in olfactory mechanism. Current understandings of olfactory molecular events in O. furnacalis, mainly involving sex pheromones and olfactory proteins, were summarized to provide a reference for further studies. O. furnacalis sex pheromone contains two components E-12-tetradecenyl acetate and Z-12-tetradecenyl acetate, which may be recognized and bound by the pheromone binding proteins OfurPBP3 and OfurPBP2, and then transported to the odorant receptors (ORs)OfurOR4 and OfurOR6 to activate them. The ORs OfurOR8, OfurOR7 and OfurOR5b mainly respond to the sex pheromone components of other Ostrinia species, E-11-tetradecenyl acetate, Z-11-tetradecenyl acetate and Z-9-tetradecenyl acetate. The OROfurOR27 responds strongly to plant odorants nonanal, octanal and 1-octanol. Much work remains to be done to fully understand odorants with olfactory activity to O. furnacalis and the functions of its olfactory proteins. These studies will help to reveal olfactory mechanism in O. furnacalis, with the aim of regulating its behaviors to control this pest.

Asian corn borer (Ostrinia furnacalis Gn., Lepidoptera: Crambidae): Attraction to a bisexual lure and comparison of performance with synthetic sex pheromone

AbstractHost plant-derived semiochemicals are becoming the most promising attractants to lure corn borers to traps in the field. Following success with the European corn borer (Ostrinia nubilalis), a two-component blend bisexual lure (phenylacetaldehyde and 2-(4-methoxyphenyl)ethanol) of the host plant odor was tested in wind tunnel and field trapping experiments on the Asian corn borer (Ostrinia furnacalis) (ACB). To be able to compare the lure's performance with synthetic pheromone, a new route for the sex pheromone components (Z)-12-tetradecenyl acetate and (E)-12-tetradecenyl acetate was also developed, and the biological activity of the products was confirmed. The bisexual lure attracted both males and females of ACB in laboratory wind tunnel, and also in the field. Field trapping results indicated that traps with the bisexual lure attracted somewhat more ACB (both sexes) than pheromone baited traps, but this indication needs further confirmation. Traps baited with the bisexual lure may offer a new tool for monitoring ACB for practical purposes.

Neuropeptide F regulates feeding via the juvenile hormone pathway in Ostrinia furnacalis larvae.

Feeding by pests is one of the most important reasons for reductions in agricultural crop yield. This study aimed to reveal how juvenile hormone (JH) participates in larval feeding regulation of the Asian corn borer Ostrinia furnacalis. Larvae of O.furnacalis exhibit a daily circadian feeding rhythm, with a peak at ZT18 and a trough at ZT6 under both photoperiod (LD) and constant dark (DD) conditions, which may be eliminated by application of fenoxycarb, a JH active analogue. JH negatively regulates larval feeding as a downstream factor of neuropeptide F (NPF), in which knocking down JH increases larval feeding amount along with body weight and length. The production of JH in the brain-corpora cardiaca-corpora allata (brain-CC-CA) is regulated by brain NPF rather than gut NPF, which was demonstrated in Drosophila larvae through GAL4/UAS genetic analysis. In addition, feeding regulation of JH is closely related to energy homeostasis in the fat body by inhibiting energy storage and promoting degradation. The JH analogue fenoxycarb is an effective pesticide against O.furnacalis, controlling feeding and metabolism. The brain NPF system regulates JH, with functions in food consumption, feeding rhythms, energy homeostasis and body size. This study provides an important basis for understanding the feeding mechanism and potential pest control of O.furnacalis. © 2022 Society of Chemical Industry.

Hemocyte response to treatment of susceptible and resistant Asian corn borer (Ostrinia furnacalis) larvae with Cry1F toxin from Bacillus thuringiensis

Midgut receptors have been recognized as the major mechanism of resistance to Cry proteins in lepidopteran larvae, while there is a dearth of data on the role of hemocyte's response to Cry intoxication and resistance development. We aimed at investigating the role of circulating hemocytes in the intoxication of Cry1F toxin in larvae from susceptible (ACB-BtS) and resistant (ACB-FR) strains of the Asian corn borer (ACB), Ostrinia furnacalis. Transcriptome and proteome profiling identified genes and proteins involved in immune-related (tetraspanin and C-type lectins) and detoxification pathways as significantly up-regulated in the hemocytes of Cry1F treated ACB-FR. High-throughput in vitro assays revealed the binding affinity of Cry1F with the tetraspanin and C-type lectin family proteins. We found significant activation of MAPKinase (ERK 1/2, p38α, and JNK 1/2) in the hemocytes of Cry1F treated ACB-FR. In testing plausible crosstalk between a tetraspanin (CD63) and downstream MAPK signaling, we knocked down CD63 expression by RNAi and detected an alteration in JNK 1/2 level but a significant increase in susceptibility of ACB-FR larvae to Cry1F toxin. Information from this study advances a change in knowledge on the cellular immune response to Cry intoxication and its potential role in resistance in a lepidopteran pest.