Important Pest Research Articles

Global Potential Geographic Distribution of Anthonomus eugenii Under Climate Change: A Comprehensive Analysis Based on an Ensemble Modeling Approach.

Climate warming is affecting the ranges and population dynamics of invasive species, including insects, which have become a global problem, causing biodiversity declines and agricultural economic losses. Anthonomus eugenii as an important invasive pest on pepper is now mainly located in the USA and Mexico. However, the global potential geographic distribution (PGD) of A. eugenii with climate change remains unknown, which makes it difficult to monitor and control. In this study, based on the global distribution areas and important environmental variables, we constructed an ensemble model to predict the global PGD of A. eugenii under the current climate and three climate scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) in the 2030s and 2050s. The mean true skill statistics (TSS) and the area under the receiver operating characteristic curve (AUC) of the EM were 0.825 and 0.988, respectively, indicating that the EM was reliable. The mean temperature of the driest (bio9) and wettest (bio8) quarter and precipitation of the coldest quarter (bio19) were the most important environmental variables affecting the PGD of A. eugenii. Under the current climate, the PGD of A. eugenii was mainly concentrated in southern North America and central South America. The suitable areas of A. eugenii could increase significantly, reaching the maximum under SSP5-8.5 in the 2030s, approximately 1911.7 × 104 km2. Moreover, the distribution centroid would shift to higher latitudes with global warming. It also had the potential invasion risk in Russia, China, the Republic of the Congo, and Romania, which should enhance quarantine control and early warning.

Transcriptome and Neuroendocrinome Responses to Environmental Stress in the Model and Pest Insect Spodoptera frugiperda

The fall armyworm, Spodoptera frugiperda, is one of the most notorious pest insects, causing damage to more than 350 plant species, and is feared worldwide as an invasive pest species since it exhibits high adaptivity against environmental stress. Here, we therefore investigated its transcriptome responses to four different types of stresses, namely cold, heat, no water and no food. We used brain samples as our interest was in the neuroendocrine responses, while previous studies used whole bodies of larvae or moths. In general, the responses were complex and encompassed a vast array of neuropeptides (NPs) and biogenic amines (BAs). The NPs were mainly involved in ion homeostasis regulation (ITP and ITPL) and metabolic pathways (AKH, ILP), and this was accompanied by changes in BA (DA, OA) biosynthesis. Cold and no-water stress changed the NP gene expression with the same patterns of expression but clearly separated from each other, and the most divergent pattern of expression was shown after no-food stress. In conclusion, our data provide a foundation in an important model and pest insect with candidate NPs and BAs and other marker candidate genes in response to environmental stress, and also potential new targets to manage pest insects.

The Utilization of Inert Materials for the Control of Stored-Product Mites—A Mini Review

Stored-product mites are important pests of stored products, while their presence in storage and processing facilities has a significant effect on public health. On the other hand, inert materials are promising alternatives to conventional pesticides in stored product protection and have provided very good results against storage insects. These formulations can be applied either directly on the product or on surfaces, as dusts or as slurry formulations. In the current paper, we review the factors that affect the efficacy of inert dusts, emphasizing in diatomaceous earths, against stored-product mites. Hence, we address the different biotic and abiotic factors that affect the acaricidal effect of inert materials against different mite species, but also the complexity of such an application, that often arises from the simultaneous presence of plant-feeding mites with their mite predators. Finally, we provide some insights for further research directions.

Potential global distributions of an important aphid pest, Rhopalosiphum padi: insights from ensemble models with multiple variables.

Species distribution modeling is extensively used for predicting potential distributions of invasive species. However, an ensemble modeling approach has been less frequently used particularly pest species. The bird cherry-oat aphid Rhopalosiphum padi L. is an important pest of wheat (Triticum aestivum L.) worldwide and causes 30% yield losses. Here, we developed a series of ensemble models with multiple variables to predict the habitat suitability of this pest at a global scale. The current suitable habitat for R. padi is mainly distributed in East Asia, South Asia, Europe, southern North America, southern South America, eastern Australia, and New Zealand. The highly suitable regions are primarily distributed in east of China, Japan, most of North America, southeastern South America, most of Europe, and southeastern edge of Australia. In future scenarios, the suitable habitats will undergo a significant contraction overall northward, and no moderately nor highly suitable habitats are predicted for this pest in other areas. Our findings indicate that a high risk of R. padi outbreaks currently exists for the highly suitable regions mentioned above, especially with wheat cultivation, but the capacity of R. padi to cause such outbreaks will weaken in the future. Climate-associated factors are significantly more important than land use, elevation and host-plant factors, and the BIO11 (mean temperature of the coldest quarter), in particular, predominated in shaping projections of R. padi's distribution. The predicted distribution pattern and key ecological factors affecting this pattern identified herein could provide important guidance for developing management policies targeting this economically important pest.

Pest and Disease of Honeybee and their Control Strategies: A Review

Apiculture is an intergral part of agricultural activity practiced to produces hive products such as honey and beeswax. The honeybees are the best pollinator which enhace crop productivity. Common pest and disease that affect honeybee with their controlling mechanism was the main objective of this review. The bees are susceptible to a number of insect pest’s types that will adversely affect the productivity of the bee colony to a significant level. Varroa destructor, Nosema ceranae, Nocema Apis, Acarapis woodi, small wax moths, Bee lice, Ants and Wax moth are the most economically important honeybee pest and disease types. To control pest and diseae different controlling mechanism are are used at different areas of the country. Nonchemical approaches in integrated pest management (IPM), traditional method and biological control are the prevention strategies. This overview forms the basis to realize the importance of pest management in bee husbandry practices, thus affecting the resilience and productivity of honeybee populations.

Phytochemical properties and insecticidal activity of hexane extract of Melia azedarach fruit against Tuta absoluta (Meyrick)

The tomato leaf miner (TLM), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is important pest on tomato, potato and other Solanaceous with a huge economic importance. Management of the pest can be problematic, especially when the infestation pressure is high. Phytochemical and contact toxicity of the hexane extract of Melia azedarach L. (MA) fresh fruit on the developmental stage of egg, the 2nd larval instars and pupae of T. absoluta were evaluated in the laboratory condition, 27 ± 2 °C, 65 ± 5% relative humidity and 16 Light:8 Dark hours photoperiods. The findings showed that the hexane extract of M. azadrach is harmful to T. absoluta at various stages, including larvae and pupae. The major components in the extract were 9,12-Octadecadienoic acid (Z,Z)- methyl ester (69.375%), 9-Octadecenoic acid (Z)- methyl ester (17.231%) and Hexadecanoic acid, methyl ester (7.361%), respectively. Analysis of probit data showed that LC50 for MA extract on egg, 2nd instar larvae, and pupae were found to be 948.93, 346.72 and 1.75 μl/ml, respectively. Sublethal concentrations had significant impact on the nutrition of T. absoluta larvae (p < 0.001). The results showed that the extract controls T. absoluta in open and closed environments and is recommended for protecting the environment and the health of users.

CaCO3-coated indoxacarb deep eutectic solvent complexed with diatomaceous earth improves insecticidal activity against the red imported fire ants.

The red imported fire ants (RIFAs) are a globally important invasive pest that severely affects the ecosystem and human health, and its current control is primarily through chemical pesticides. However, the extensive use of chemical pesticides causes environmental problems, and alternative strategies for controlling this pest are being explored. In our study, we aimed to design a deep eutectic solvent (DES)-CaCO3 system in which RIFAs were used as target insects to increase the lethal activity and behavioural regulation effects on RIFAs via contact and feeding. Indoxacarb (IDC) was made into DESs with three fatty acids, oleic acid (OA), linoleic acid (LA), and linolenic acid (LNA), which showed a significant increase in lethal activity against worker ants compared with IDC. OA@IDC@CaCO3, LA@IDC@CaCO3, and LNA@IDC@CaCO3 nanoparticles were prepared via interfacial precipitation. Characterization of the structures of the three pesticide-carrying nanoparticles revealed that all three fatty acid eutectic solvents formed spherical CaCO3 nanoparticles, with average particle sizes between 0.59 and 0.90 μm, which increased with increasing degree of fatty acid unsaturation. The pesticide loading ranged from 2.13 %⁓3.43 %, and the surfaces were all positively charged and well dispersed. OA@IDC@CaCO3 was relatively more effective and was able to dramatically inhibit the abandonment and foraging behaviours of RIFAs, prolong the time required for these behaviours, and decrease the number of feeding worker ants and the amount of food consumed. OA@IDC@CaCO3 was subsequently compounded with diatomaceous earth (DA), and spiked into baits, which significantly increased the contact and feeding activity of worker ants, inhibited the feeding, digging, and corpse-discarding behaviours of RIFAs. In the field trial, the combined control effect of the DA + OA@IDC@CaCO3 group was 83.38 %, which was greater than the 69.65 % of the commercial agent control group. In this study, IDC bait was co-prepared by using acid as a comelting solvent, CaCO3 as a coating, and DA as a pesticide adjuvant, which improved the activity against RIFAs, prolonged the holding period of IDC, and improved the prevention and control of RIFAs. Therefore, our research provides a simple and feasible approach for designing and constructing novel nanopesticides for RIFAs control.

Control of the weevil with Beauveria sp. in stored corn

The corn weevil (Pagiocerus sp.) is a pest of economic importance stored in corn grains (Zea mays L.). Their control is realized with systemic insecticides, which can cause resistant insects. To search for a biological control method, the entomopathogenic fungus Beauveria was evaluated by spraying stored corn grains attacked by Pagiocerus. The results indicated the pre-insect placement application of the native strain of Beauveria sp. with a dosage of 3 mL-1, it reached 100% insect mortality, while the commercial strain reached 83% mortality. The percentage of damaged grains for the native isolate was 26% and 56% for the commercial isolate with pre-insect placement application of 3 mL-1, unlike the control treatment that reached 80% of damaged grains. The weight loss of grains with the pre-insect placement application of the native isolate with a dosage of 3 mL-1 registered the lowest percentage at 29.9%. In contrast, the commercial isolate registered a weight loss of 56.2%, unlike the control treatment, which registered 85.2%. The study demonstrated that Beauveria applied in suspension with concentrations of 1 x 108 conidia mL-1 can control Pagiocerus for stored corn grains.

Population trends of the sugarcane leaf hopper Pyrilla perpusilla (Walker) (Homoptera: Lophopidae) and its parasitoids in relation to weather factors in the Tarai region of Uttarakhand, India

Abstract Background Pyrilla perpusilla (Walker) is an important pest of sugarcane ecosystem in the Tarai region of Uttarakhand state of India. The study focused on investigating the population dynamics of Pyrilla (sugarcane leaf hopper) and its parasitoids under the natural field conditions. Results During the study, two important parasitoids, viz., Fulgoraecia Melanoleuca, a nymphal/adult parasitoid (Lepidoptera: Epipyropidae), and Cheiloneurus pyrillae, an egg parasitoid (Hymenoptera: Encyrtidae), were found associated with the sugarcane leaf hopper. The peak mean population of ecto-parasitoid, F. melanoleuca cocoon, was observed in November 2022–23 and 2023–24. The morning hour relative humidity showed a negative significant relation with the cocoon population. The maximum parasitization of nymphs and adults Pyrilla was found to be 46.7 and 46.0%, respectively, from September to October during 2022–23 and 2023–24 crop seasons, after that the declining trend in parasitization by F. melanoleuca was observed. An increasing trend was recorded in egg parasitization in July, when the maximum mean population density of Pyrilla egg batches (2.28 /leaf), nymphs (4.75/leaf) and adults (4.58/leaf) was found. Temperature and relative humidity had significant correlations with Pyrilla egg batches. Conclusion Overall, the study outlines the presence of Pyrilla and its naturally occurring parasitoids in the sugarcane ecosystem, along with the effects of weather conditions on Pyrilla’s population density and the parasitization rates of the parasitoids. The peak activity period of pest and its parasitoids was reported from September to November. Weather factors such as temperature ranging from 16 to 37.25 °C and relative humidity (62.7–93.8%) played a significant role in affecting their density and parasitization.

Phenotypic evaluation of Ptb 33 introgressed rice lines for resistance to brown planthopper, Nilaparvata lugens (Stål)

Brown planthopper (BPH), Nilaparvata lugens (Stal) continues its dominantce as an important pest in rice and cause considerable yield loss. Ptb 33 is a well-known source of resistance to BPH. Introgressed lines from Ptb 33 were evaluated against BPH using various parameters of resistant mechanisms. Initial screening was done by protray and modified seedbox screening tests. Eight entries illustrate resistance to BPH in mass screening. Further experiments assessed the mechanisms viz., antibiosis, antixenosis and tolerance in selected resistant entries. Antibiosis studies revealed reduced honeydew excretion, lower nymphal survival rates and prolonged developmental periods in resistant lines compared to the susceptible check. Antixenosis was evaluated through nymphal settling preference tests, with resistant entries showing reduced BPH attraction over time. Tolerance parameters, including Functional Plant Loss Index (FPLI) and Plant Dry Weight Loss Index (PDWLI), indicated varying levels of resistance among the introgressed lines. Among the entries identified as resistant through screening, FSR-3 exhibited strong resistance across all three mechanisms, while X21302-145 showed excellent antibiosis but poor tolerance character. Correlation analysis revealed significant interrelation between various resistance parameters. The study identifies promising BPH-resistant rice lines and elucidates their underlying resistance mechanisms, contributing valuable insights for rice breeding programs in developing durable BPH-resistant cultivars.

SgR1, Encoding a Leucine-Rich Repeat Containing Receptor-like Protein, Is a Major Aphid (Schizaphis graminum) Resistance Gene in Sorghum.

Greenbug, Schizaphis graminum, is one of the important cereal aphid pests of sorghum in the United States and other parts of the world. Sorghum bicolor variety PI 607900 carries the Schizaphis graminum resistance (SgR1) gene that underlies plant resistance to greenbug biotype I (GBI). Now, the SgR1 has been determined as the major gene conferring greenbug resistance based on the strong association of its presence with the resistance phenotype in sorghum. In this study, we have successfully isolated the SgR1 gene using a map-based cloning approach, and subsequent molecular characterization revealed it encodes a leucine-rich repeat containing receptor-like protein (LRR-RLP). According to DNA sequence analysis, the SgR1 gene are conserved among GBI-resistance sorghum accessions but are variable within susceptible lines. Furthermore, an InDel (-965 nt) at its promoter region and a single-nucleotide polymorphism (SNP, 592 nt) in the CDS of the SgR1 were detected and they are well conserved within resistant genotypes. When the SgR1 gene was cloned and transferred into Arabidopsis plants, the SgR1 was activated in the transgenic Arabidopsis plants in response to attack by green peach aphids according to the results of the histochemical assay, and GUS activity was detected in situ in spots around the vasculature of the leaf where the phloem is located, suggesting its biological function in those transgenic Arabidopsis plants. Overall, this study confirms that the SgR1 gene coding for an LRR-RLP is the major resistance gene to greenbug, a destructive pest in sorghum and wheat. This represents the first greenbug resistance gene cloned so far and indicates that the simple-inherited GBI resistance gene can be used for sorghum improvement with genetic resistance to GBI via molecular breeding or cross-based conventional breeding technologies.

The effect of synergists on the inhibition of detoxification enzyme activities and acaricide sensitivity in Rhizoglyphus robini.

The saffron bulb mite, Rhizoglyphus robini Claparede (Acari: Acaridae), is the most important pest of the saffron crop in Iran. This pest attacks and feeds on saffron corms. For this reason, the corms are treated with acaricides before planting. The high activity of detoxification enzymes in arthropods may reduce their pesticide sensitivity. Diethyl maleate (DEM) is an inhibitor of glutathione S-transferases (GSTs), piperonyl butoxide (PBO) is an inhibitor of cytochrome P450 monooxygenases, and triphenyl phosphate (TPP) is an inhibitor of esterase activity. A filter paper method was used to determine the efficiency of these synergists in inhibiting the activity of detoxifying enzymes of R. robini. Adult mites were treated with these three synergists for 6, 12, 24, and 48 h, respectively. The activity of each detoxifying enzyme was measured and compared to the control treatment, and the inhibition percentage was calculated each time. The results showed that DEM reduced GST activity by 59.9% after 48 h, PBO inhibited cytochrome P450 activity by 30%, and TPP suppressed esterase activity by 38.5%. The most statistically significant inhibition occurred 24 h after pretreatment with each synergist. Bioassays with 24 h pretreatment showed that the sensitivity of R. robini to propargite increased by 1.6 times with PBO, 1.7 times with TPP, and 2.5 times with DEM. In conclusion, synergists and efficient inhibition of detoxifying enzymes can play a significant role in increasing the sensitivity of agricultural pests to pesticides and can be considered in managing pesticide resistance.

Bio-Efficacy of Cloves &lt;i&gt;Syzygium aromaticum&lt;/i&gt; against Pulse Beetle &lt;i&gt;Callosobruchus chinensis&lt;/i&gt;

The pulse beetle Callosobruchus chinensis (Coleoptera: Bruchidae), is a significant pest of stored grains, particularly pulses, poses health and economic risks. The efficacy of botanical insecticides specifically clove against pulse beetles, reared on stored grains, was evaluated in this study. Laboratory bioassays were conducted to assess the effect of clove on % infestation of whole moong seeds, eclosion of adults, and the sex ratio. It was observed that though there was no significant difference in the % infestation in ‘control’ and ‘test’ conditions, there was a significant difference in the ratio of males to females that emerged in the two conditions. The mean sex ratio was 0.77:1 in ‘control’ and 1.05:1 in ‘test’ conditions. It indicates that it would consequently lead to significant reduction in the population buildup of pulse beetles owing to the lesser number of females that emerged in the test condition in which a clove was kept along with whole moong seeds. The results of this preliminary study are quite encouraging and indicate the potential of clove as a ready-to-use condiment in the management of pulse beetles in an effective, economical and eco-friendly manner. Further studies are in progress to evaluate the effect of clove in different forms on the various behavioural responses of this economically important pest of stored grains, which could help in its management in an integrated manner.

A new species in the mealybug genus Pseudococcus Westwood (Hemiptera: Coccomorpha: Pseudococcidae) from Indonesia

The mealybug genus Pseudococcus Westwood (Hemiptera: Coccomorpha: Pseudococcidae) contains several important agricultural and/or horticultural pests in southern Asia, where information on species diversity and distributions is still incomplete. While studying the mealybug fauna in southern Sumatra, Indonesia in 2022, an undescribed species of Pseudococcus on Piper aduncum L. (Piperaceae) was collected. The species is described as Pseudococcus iffahae Zarkani &amp; Kaydan sp. nov.; it has similarities with P. philippinicus Williams, P. longispinus (Targioni Tozzetti) and P. odermatti Miller &amp; Williams, with which it is compared. Photomicrographs and a taxonomic illustration of P. iffahae, and an identification key to species of Pseudococcus recorded in Indonesia, Southeast and southern Asia, are provided.

Sustainable management of potato tuber moth in storages using entomopathogenic fungi and an ectoparasitic mite.

The potato tuber moth (PTM), Phthorimaea operculella, is an economically important pest of potato crops worldwide. So far, the application of chemical pesticides is the major measure to manage PTM, but it induces serious deleterious impacts on the environment and human health. Here, we screened the entomopathogenic fungi that are lethal to PTM, and tested their sublethal impacts on PTM development, mortality, and reproduction as well as that of ectoparasitic mite Pyemotes zhonghuajia, a natural enemy of PTM. Among 13 tested entomopathogenic fungal strains in three genera, Beauveria Vuillemin, Cordyceps Fries, and Talaromyces Benjamin, Cordyceps fumosorosea (strain KY1136) and Beauveria bassiana (strain KY1115) caused a significantly higher mortality in PTM eggs, larvae, and pupae. Median lethal concentration (LC50) of both strains prolonged PTM immature development, shortened adult longevity, and reduced fecundity and life table parameters in terms of intrinsic rate of increase (rm), net reproductive rate (R0), and finite rate of increase (λ). The LC50 value of KY1136 (1.9 × 106 spores/mL) was lower than that of KY1115 (9.0 × 106 spores/mL), indicating the greater potential for biological control of PTM by KY1136. Both strains had no significant impact on P. zhonghuajia survival and reproduction. Increasing P. zhonghuajia density reduced PTM feeding and pupation rate, while the combined application of P. zhonghuajia and entomopathogenic fungi had no additional effect in inhabiting PTM feeding and pupation. Entomopathogenic fungal strains Cordyceps fumosorosea KY1136 and Beauveria bassiana KY1115 are the potential biological control agents of PTM, but do not impose a negative impact on the natural enemy. Our study provides insights into the integrated pest management of PTM by combining the entomopathogenic fungi and an ectoparasitic mite. © 2024 Society of Chemical Industry.

First Activity of Aspergillus flavus as Entomopathogen Infecting Diaphania indica and Control Efficacy Across Different Developmental Stages

Diaphania indica (Lepidoptera: Crambidae) is one of the most important pests infesting many cucurbitaceous vegetables. During the rearing of insect eggs, we observed a fungal infection in these insect eggs which causes the death of pests. Therefore, this work aimed to isolate and identify this fungus by amplifying the internal transcribed spacer (ITS) region of the rDNA, as well as evaluating the efficiency of this fungus in control. Aspergillus flavus, ‘PP125556’, showcased robust pathogenicity against a range of D. indica pests. The results showed that colonies of ‘PP125556’ cultivated on potato dextrose agar (PDA) exhibited distinctive morphological characteristics, transitioning from pristine white to verdant green. Bioassays demonstrated concentration-dependent mortality rates of D. indica larvae and adults when exposed to varying concentrations of ‘PP125556’ conidia, with the highest concentration (1 × 109 conidia/mL) inducing significant death, with the highest mortality (53.06% for eggs, 70.57% for larvae, and 86.65% for adults). Furthermore, examination under a stereomicroscope revealed conspicuous external symptoms in infected larvae, including reduced mobility, darkened body pigmentation, and the emergence of white hyphae, indicative of mortality. Additionally, infected eggs exhibited inhibited hatching and the emergence of green hyphae, while infected adults displayed mortality and white hyphae colonization, underscoring the potent biocontrol efficacy of A. flavus ‘PP125556’ against D. indica across diverse developmental stages.

Invasion History and Dispersion Dynamics of the Mediterranean Fruit Fly in the Balkan Peninsula.

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann 1824; Diptera, Tephritidae), is considered one of the most important pests, infesting more than 300 species of fresh fruit and vegetables worldwide. The medfly is an important invasive species, which has spread from the eastern part of sub-Saharan Africa to all of the world's continents in recent centuries. Currently, the medfly is expanding its geographical range to cooler, temperate areas of the world, including northern areas of Mediterranean countries and continental areas of Central Europe. We collected and analysed all the available information, including in historical records, on the phenology of the medfly in the Balkan Peninsula, to map and understand the path of invasion and spread dynamics on the northern Mediterranean coast and in Central Europe. The medfly was first recorded in the Balkan Peninsula in 1915, in the Aegean area on the island of Aigina, followed by a few records on its presence in the Peloponnese in the early 1930s and throughout the Adriatic coastal area in the 1950s; it was first detected on the Croatian coast in 1947. By 2010, the medfly had been detected along the entire Ionian coast, while the first record of its presence on the Balkan coast of the Black Sea was made in 2005. Since 2000 to date, there has been a significant increase in the frequency of medfly detections in the interior of the Balkan Peninsula, including occasional detections in areas with unfavourable climatic conditions for overwintering, which seems to be favourable for reproduction during the summer and lead to significant infestation of late ripening fruits (late summer and autumn). In the last 20 years, the medfly has spread to more northerly areas (43 to 45 degrees latitude) and has been detected at higher altitudes (>200 to 600 m). Along the Balkan Peninsula, the infestation of fruits from 25 host plant species, from 14 genera and 10 plant families, has been reported. Considering the extremely high invasiveness of the medfly and its wide distribution in several Balkan regions with different climatic conditions, we can assume that it is adapting to new climatic conditions and infesting new host plants.

Contact toxicity and feeding deterrent activity of Dennettia tripetala Bak. and Jatropha curcas L. leaf extracts against Spodoptera frugiperda J. E. Smith

BackgroundMaize (Zea mays L.) is an important annual cereal crop with nutritional benefits, but its production is constrained by activities of insect pests. The fall armyworm (Spodoptera frugiperda) is one of the important economic pests that limits the production of maize, causing several damages on maize fields. Synthetic insecticides are commonly used to manage fall armyworm, but they have undesirable side effects on human and the environment. This study aimed to evaluate the contact toxicity and feeding deterrent activities of ethyl acetate and methanol leaf extracts of Dennettia tripetala and Jatropha curcas against fall armyworm.ResultsIn the contact toxicity of Dennettia tripetala and Jatropha curcas extracts, larval mortality increased with an increase in exposure time and concentrations. The extracts possessed significant contact insecticidal effects that ranged between 20.00 ± 13.94% and 100.00 ± 0.00%. Also, in the feeding deterrent activity test, extracts revealed significant differences (p < 0.05) in larva mortality and duration. Larva duration ranged from 56.67 ± 14.91% to 100.00 ± 0.00%. The larval stages of S. fruiperda that were artificially treated with the concentrations of the extract were shorter than those that were exposed to the control treatments. The methanol leaves extracts of Dennettia tripetala and Jatropha curcas showed no significant difference (p > 0.05) in the pupal mortality and pupal weight among the treatments. Jatropha curcas ethyl acetate and Jatropha curcas methanol extracts had high flavonoid content, and tannin and phenol content was higher in Dennettia tripetala ethyl and methanol extracts.ConclusionsFrom this study, ethyl acetate and methanol leaf extracts (75% and 100% v/v concentrations) are effective as contact and stomach poisons against fall armyworm and suitable replacements for synthetic pesticides.

Assessing the Impact of Tephritid Fruit Flies on Diverse Fruit and Vegetable Crops in West Bengal's Terai Agro-ecological Region

The flies belong to the family Tephritidae of the Insect order Diptera and are referred to as Fruit flies because they infest various fruits and vegetables. Globally, Dacinae fruit flies of the genus Bactrocera Macquart are one of the most important pests of fruits and vegetables. A study was conducted during 2021, to assess the association of tephritids with different fruits and vegetables like Ber, Citrus, Guava, Mango, Bottle gourd, Cucumber and Pumpkin. A total of nine species were collected by installing traps comprising of sex attractants such as Cue-lure, Methyl Eugenol and by rearing from Infested fruits. Among nine, six species were collected through cue-lure traps namely Zeugodacus tau (Walker), Zeugodacus cucurbitae (Coq.), Bactrocera rubigina (Wang and Zhao), Zeugodacus caudatus (Fabricus), Bactrocera divenderi (Maneesh, Hancock and Prabhakar) and Dacus longicornis (Wiedemann). Two species were collected through methyl eugenol traps namely Bactrocera dorsalis (Hendel) and Bactrocera zonata (Saunders). Four species namely Zeugodacus tau (Walker), Zeugodacus cucurbitae (Coq.), Bactrocera dorsalis (Hendel) and Bactrocera minax (Enderlein) were recovered from infested fruits of ber, citrus, bottle gourd, cucumber and pumpkin. Species richness in different fields was maximum in citrus and from the recovery of infested fruits maximum in ber. Species composition of Z.tau was maximum in pumpkin, and bottle gourd and B. dorsalis were maximum in mango, guava, ber and citrus. Species composition of Z. tau were recovered maximum from infested pumpkin and cucumber, Z. cucurbitae were recovered maximum from infested bottle gourd and B. dorsalis were recovered maximum from infested ber and citrus fruits. Relative abundance of Z. tau was recorded maximum in pumpkin and bottle gourd and B. dorsalis was recorded maximum in mango, guava, ber and citrus. A relative abundance of Z. tau was recovered maximum in pumpkin and cucumber-infested fruits, Z. cucurbitae were recovered maximum from bottle gourd-infested fruits and B. dorsalis were recovered maximum from ber and citrus-infested fruits. In different fields, species evenness was observed maximum in citrus and from recovery of infested fruits maximum in ber.

Two detoxification enzyme genes, CYP6DA2 and CarFE4, mediate the susceptibility to afidopyropen in Semiaphis heraclei.

Semiaphis heraclei is an important economic pest affecting Caprifoliaceae and Apiaceae plants, and chemical control is still the main effective control method in the field. Afidopyropen is a new type of pyridine cyclopropyl insecticide, which can effectively control piercing-sucking mouthparts pests and is suitable for pest resistance management. However, the detoxification mechanism of S. heraclei to afidopyropen is still poorly cleared. The insecticidal activity of afidopyropen against S. heraclei and the enzyme activity assay and synergism bioassay were evaluated. The detoxification enzyme genes were obtained by transcriptome and validated by quantitative real-time PCR (RT-qPCR). Furthermore, RNA interference was used to study the functions of detoxification enzyme genes. The activities of cytochrome P450 monooxygenases (P450s) and carboxylesterases (CarEs) were significantly increased under afidopyropen treatment. The toxicity of afidopyropen against S. heraclei was significantly increased after application the inhibitors of piperonyl butoxide and triphenyl phosphate. Sixteen P450 genes and three CarE genes were identified in the transcriptome of S. heraclei. The RT-qPCR results showed that eleven P450 genes and two CarE genes were significantly upregulated under afidopyropen treatment, and the expression of CYP6DA2 and CarFE4 was upregulated by more than 2.5 times. The expression pattern of CYP6DA2 and CarFE4 was further analyzed in different developmental stages of S. heraclei and knockdown of CYP6DA2 and CarFE4 significantly increased the susceptibility of S. heraclei to afidopyropen. The results of this study uncover the key functions of CYP6DA2 and CarFE4 in the detoxification mechanism of S. heraclei to afidopyropen, and provide a theoretical basis for the scientific use of afidopyropen in the field.