Insecticide Treatments Research Articles

Economic Assessment aganist Shoot and Fruit Borer (Lepidoptera: Noctuidae) on Okra at Uttar Pradesh, India

The field trail was conducted during Kharif 2022 to evaluate the cost benefit ratio by using different insecticidal applications viz., NSKE 10% T1 @ 10gm/L, Beauveria bassiana 1.15% WP (1x108 CFU/gm) T2 @ 5gm/L, Spinosad 45 SC T3 # 0.5ml/L, Metarhizium anisopliae 4% WSP (1x108 CFU/gm) T4 @ 5ml/L, Imidacloprid 17.8 SL T5 @ 0.3 ml/L, Nisco sixer plus T6 @ 1.5ml/L, Neem oil 5% T7 @ 5ml/L and untreated control T8 in three replications against shoot and fruit borer, Earias vittella (Lepidoptera: Noctuidae), management on okra. Obsevations were taken on percent infestation of shoot and fruit on day before, 7DAS and 14DAS after two sprays Results revealed that highest yield is recorded in Spinosad 45 SC (101.4 q/ha), followed by nisco sixer plus (82.2 q/ha), Imidacloprid 17.8 SL (72.5 q/ha). Insecticidal treatment with Spinosad 45 SC with 1:5.66 had the highest cost benefit ratio, followed by Nisco sixer plus (1:4.99).

Residual effect of dinotefuran and nitenpyram against adult <i>Liothrips wasabiae</i> (Thysanoptera: Phlaeothripidae)

Liothrips wasabiae (Thysanoptera: Phlaeothripidae) is an important insect pest of water wasabi (Eutrema japonicum). The area infested by L. wasabiae becomes black-spotted. Water wasabi requires a long cultivation period of approximately 1.5–2 years. However, chemical insecticides to control L. wasabiae can only be applied a maximum of three times according to the pesticide regulation. Therefore, two insecticides, dinotefuran and nitenpyram, that have been demonstrated to be highly effective, were investigated for their residual effect against L. wasabiae. Results showed that when adult L. wasabiae were released 28 days after insecticide treatment, dinotefuran caused a mortality of 56% compared to 10% with nitenpyram.

Effect of Seed Fungicide Treatment, Microelement Fertilizer and Mepiquat Chloride Applications on Yield and Yield Components of Peanut

Seed treatment against soil pests and soil-borne pathogenic fungi, foliar application of microelement and mepiquat chloride at flowering and after flowering periods promise to increase peanut (Arachis hypogaea L.) yield. A two-year field study was conducted to test this hypothesis by seed fungicide and insecticide treatment, foliar micronutrient and mepiquat chloride (Pix) applications at different combinations and different growth stages of peanut in the eastern Mediterranean region. The treatments were different combinations of Vitavax (200 g/L Carboxin + 200 g/L Thiram) 400 g/L 100 kg seed, Gaucho (600 g/L Imidacloprid) 800 g/L 100 kg seed, Fertilon Combi (Fe, Zn, B, Mn, Cu, Mn and Mo) 1000 g /ha and Pix (150 cc /ha mepiquat chloride). Peanut seeds were treated with fungicide and insecticide before planting. Microelement fertilizer and Pix combinations were applied at the beginning of flowering, after flowering and at the beginning of flowering + after flowering. The best results for seed kernel ratio, 100 seed weight and pod yield were obtained from Pix + Fertilon Combin treatment after flowering. This treatment was followed by Goucho + Vitavax seed treatment before planting + Pix application after flowering. In this study, it was observed that Goucho + Vitavax seed treatment and Pix, Fertilon Combi and Pix + Fertilon Combi applications at flowering, after flowering and at flowering + after flowering applications generally contributed pod yield increases.

Effect of several reduced-risk insecticides on the population of Bemisia tabaci Genn. and incidence of pepper yellow leaf curl Indonesia virus (PepYLCIV) on chili plants

Tobacco whitefly, Bemisia tabaci Genn. can directly, and indirectly damage chili plants by sucking the plant sap and transmitting Pepper yellow leaf curl Indonesia virus (PepYLCIV), respectively. Farmers control PepYLCIV by using synthetic insecticides with 2-3 applications a week to suppress the vector population. The intensive use of insecticide raises concern about potential detrimental effects on the environment and non-target organisms. An alternative control measure for B. tabaci is the use of reduced-risk insecticides that are effective but safer. Thus, the study aimed to determine the effectiveness of various reduced-risk insecticides in reducing the whitefly population and PepYLCIV incidence. This experiment consisted of 12 treatments using insecticides of abamectin, azadiractin, imidacloprid, deltamethrin, spinosad, and water (control), applied once and twice a week. The results showed that the low-risk insecticides had no significant effect on the numbers of adults and nymphs of B. tabaci and the PepYLCIV incidence. Imidacloprid had significantly lower egg number and PepYLCIV incidence than the control and the other insecticide treatments. Our results also showed that B. tabaci populations were low throughout the season but the incidences of PepYLCIV were relatively high. This indicated a possibility that PepYLCIV is seed-borne.

Residual insecticide surface treatment for preventing malaria: a systematic review protocol

IntroductionMalaria presents a significant global public health burden, although substantial progress has been made, with vector control initiatives such as indoor residual surface spraying with insecticides and insecticide-treated nets. There now exists many different approaches to apply residual insecticide to indoor and outdoor surfaces in malaria-endemic settings, although no comprehensive systematic reviews exist evaluating these interventions. This manuscript outlines the protocol for a systematic review which aims to synthesise the best available evidence regarding full or partial indoor or outdoor residual insecticide surface treatment for preventing malaria.Methods and analysisThis review will comprehensively search the literature (both published and unpublished) for any studies investigating the effectiveness of residual insecticide surface treatment for malaria. Studies will be screened to meet the inclusion criteria by a minimum of two authors, followed by assessment of risk of bias (using appropriate risk-of-bias tools for randomised and non-randomised studies) and extraction of relevant information using structured forms by two independent authors. Meta-analysis will be carried out where possible for epidemiological outcomes such as malaria, anaemia, malaria-related mortality, all-cause mortality and adverse effects. Certainty in the evidence will be established with GRADE assessments.Ethics and disseminationA full review report will be submitted to the Vector Control & Insecticide Resistance Unit, Global Malaria Program, WHO. A version of this report will be submitted for publication in an open access peer-reviewed journal. The report will inform the development of WHO recommendations regarding residual insecticide treatment for malaria. This systematic review does not require ethics approval as it is a review of primary studies.Systematic review registrationPROSPERO 293194.

Transcriptomic Responses Underlying the High Virulence of Black Queen Cell Virus and Sacbrood Virus following a Change in Their Mode of Transmission in Honey Bees (Apis mellifera).

Over the last two decades, honey bees (Apis mellifera) have suffered high rates of colony losses that have been attributed to a variety of factors, chief among which are viral pathogens, such as deformed wing virus (DWV), whose virulence has increased because of vector-based transmission by the invasive, ectoparasitic varroa mite (Varroa destructor). A shift in the experimental mode of transmission of the black queen cell virus (BQCV) and sacbrood virus (SBV) from fecal/food-oral (direct horizontal) to vector-mediated (indirect horizontal) transmission also results in high virulence and viral titers in pupal and adult honey bees. Agricultural pesticides represent another factor that acts independently or in interaction with pathogens, and they are also thought to cause colony loss. Understanding the molecular mechanisms underlying the higher virulence following a vector-based mode of transmission provides deeper insight into honey bee colony losses, as does determining whether or not host-pathogen interactions are modulated by exposure to pesticides. Through an experimental design with controlled laboratory, we investigated the effects of the modes of transmission of BQCV and SBV (feeding vs. vector-mediated via injection) alone or in combination with chronic exposure to sublethal and field-realistic concentrations of flupyradifurone (FPF), a novel agricultural insecticide, on honey bee survival and transcription responses by using high-throughput RNA sequencing (RNA-seq) analysis. Co-exposure to viruses via feeding (VF) or injection (VI) and FPF insecticide had no statistically significant interactive effect on their survival compared to, respectively, VF or VI treatments alone. Transcriptomic analysis revealed a distinct difference in the gene expression profiles of bees inoculated with viruses via injection (VI) and exposed to FPF insecticide (VI+FPF). The number of differentially expressed genes (DEGs) at log2 (fold-change) > 2.0 in VI bees (136 genes) or/and VI+FPF insecticide (282 genes) was very high compared to that of VF bees (8 genes) or the VF+FPF insecticide treatment (15 genes). Of these DEGs, the expression in VI and VI+FPF bees of some immune-related genes, such as those for antimicrobial peptides, Ago2, and Dicer, was induced. In short, several genes encoding odorant binding proteins, chemosensory proteins, odor receptors, honey bee venom peptides, and vitellogenin were downregulated in VI and VI+FPF bees. Given the importance of these suppressed genes in honey bees' innate immunity, eicosanoid biosynthesis, and olfactory associative function, their inhibition because of the change in the mode of infection with BQCV and SBV to vector-mediated transmission (injection into haemocoel) could explain the high virulence observed in these viruses when they were experimentally injected into hosts. These changes may help explain why other viruses, such as DWV, represent such a threat to colony survival when transmitted by varroa mites.

Comparative efficacy of some botanical insecticides in the control of eggplant fruit and shoot borer (leucinodes orbonalis guenee)

An Experiment was conducted from December, 2021 to April, 2022 in an open field of the Teaching and Research Farm of Akwa Ibom State University, Obio Akpa Campused to evaluate the efficacy of botanical insecticides in the control of eggplant (Solanum melongena L.) fruit and shoot borer (EFSB) Leucinodes orbonalis Guenne), Four week-old eggplant seedlings (ARJANI FI) were transplanted to bags filled with 30kg top soil, each. There were nine insecticide treatments (T0 = Control (No insecticide), T1 = Scent leaf extract (SLE 10% w/v), T2 = Pawpaw leaf extract (PLE 10% w/v), T3 = Neem leaf extract (NLE 5% w/v), T4 = Neem oil (N.O 3% v/v), T5 = Neem oil (N.O 5% v/v), T6 = Garlic bulb extract (GBE 3% v/v), T7 = Emamectin Benzoate (EB 1.33g/L) and T8 = Neemsol (0.2% v/v). Plants were sprayed three times: four weeks after transplanting (4WAT), 6WAT and 8WAT. The experiment was laid out in a completely randomized design. Data obtained were subjected to analysis of variance and means compared at 5% probability level using Student-Newman-Keuls Test. The results obtained showed that the insecticide treated plants significantly (P< 0.05) had lower percentage of fruit and shoot infestation by EFSB relative to the untreated plants. The unsprayed plant significantly (P< 0.05) had the highest percentage of Fruit infestation by both number and weight basis. Fruits from the untreated plants had significantly (P< 0.05) more number of bored holes and larvae than the insecticide treated plants. Among the insecticide treatments, EB and N.O 5% had plants with significantly lower shoot infestation (10.42 and 12.50%), fruit infestation by weight (17.07 and 25.60%), number of larvae/fruit (0.33 and 1.00), respectively. The botanicals tested in this work could be incorporated into integrated pest management programme of eggplant fruit and shoot borer. Therefore, Emamectin Benzoate was observed to be the best and hence recommended treatment based on parameters measured.

Comparative Analysis of the Effect of Different Insecticide Treatments on Nagpur Mandarin in Biomass Accumulation

The Comparative Analysis of the Effect of Different Insecticide Treatments in Nagpur Mandarin on Biomass Accumulation was conducted during the Ambia bahar of 2009-10. The experiment was carried out on an eight-year-old Nagpur mandarin orchard with a spacing of 6.0 m x 6.0 m at Futala farm, College of Agriculture, Nagpur. The study aimed to assess the impact of different insecticide treatments on Citrus psylla management. A trial comprising of eleven treatments was set in the Randomized Block Design (RBD), replicated thrice, with each treatment plot having four plants. Four branches were selected from each plant at random and tagged. The population of citrus psylla (both nymph and adult) was counted on the twigs of 5 cm fresh growth of the shoot from all the four sides of the plant during Ambia bahar of 2009-2010. The study found that imidacloprid 0.25 ml/l, acetamiprid 0.1 g/l, and quinalphos 1 ml/l + karanj oil (pongamia oil) 10 ml/l were the most effective treatments based on biomass accumulation (wet weight basis). Meanwhile, treatments with lower efficacy were Verticillium lecani 4 g/l + mineral oil 5 ml/l, azadirachtin 2 ml/l, mineral oil 5 ml/l, and Verticillium lecani 4 g/l. Furthermore, the application of imidacloprid 0.25 ml/l, acetamiprid 0.1 g/l, thiomethoxam 0.1 g/l, and quinalphos 1 ml/l + karanj oil (pongamia oil) 10 ml/l were found to be the most effective treatments based on biomass accumulation on a dry weight basis. The results indicated that treatments with imidacloprid, acetamiprid, thiomethoxam, and quinalphos with karanj oil were the most effective in promoting higher growth of new flush, bearing (buds, flowers and fruit), and biomass accumulation on both wet weight and dry weight basis. Among them, the treatment with imidacloprid at 0.25 ml/l was found to be the most effective.

Spatial scale of non-target effects of cotton insecticides.

Plot size is of practical importance in any integrated pest management (IPM) study that has a field component. Such studies need to be conducted at a scale relevant to species dynamics because their abundance and distribution in plots might vary according to plot size. An adequate plot size is especially important for researchers, technology providers and regulatory agencies in understanding effects of various insect control technologies on non-target arthropods. Plots that are too small might fail to detect potential harmful effects of these technologies due to arthropod movement and redistribution among plots, or from untreated areas and outside sources. The Arizona cotton system is heavily dependent on technologies for arthropod control, thus we conducted a 2-year replicated field experiment to estimate the optimal plot size for non-target arthropod studies in our system. Experimental treatments consisted of three square plot sizes and three insecticides in a full factorial. We established three plot sizes that measured 144 m2, 324 m2 and 576 m2. For insecticide treatments, we established an untreated check, a positive control insecticide with known negative effects on the arthropod community and a selective insecticide. We investigated how plot size impacts the estimation of treatment effects relative to community structure (27 taxa), community diversity, individual abundance, effect sizes, biological control function of arthropod taxa with a wide range of mobility, including Collops spp., Orius tristicolor, Geocoris spp., Misumenops celer, Drapetis nr. divergens and Chrysoperla carnea s.l.. Square 144 m2 plots supported similar results for all parameters compared with larger plots, and are thus sufficiently large to measure insecticidal effects on non-target arthropods in cotton. Our results are applicable to cotton systems with related pests, predators or other fauna with similar dispersal characteristics. Moreover, these results also might be generalizable to other crop systems with similar fauna.

Management of Capsule Borer Conogethes punctiferalis (Guenee) on Castor Ricinus communis L. Using Some Plants Oil

The insecticides were tested under field conditions on the basis of percentage of capsule bore Conogethes punctiferalis (Guenee) infestation noticed under field condition. The capsule borer C. punctiferalis (Guenee) damage goes on decreasing among the chemical and plant based insecticidal treatments at first and second week after spraying. Among the eight treatments, the lowest capsule borer damage/plant recorded by T5 Mahua oil 2% with 43.55% reduction over control followed by T6 neem oil 2% recorded 36.05% reduction over control recorded during 1st week after spray. The percentage of capsule borer C. punctiferalis (Guenee) damage per plant was highest recorded by T1 treatment it was mainly due to, this treatment did not receive any insecticidal spray either chemical or plant based insecticides throughout the experimental period. Same trend was noticed after 2nd week after spray. During 2nd week after spray highest percent of reduction over control recorded by T6 neem oil 2% recorded 80.27% reduction over control followed by T7 pongamia oil 2% recorded 79.09% reduction over control. Lowest percentage of castor capsule borer C. punctiferalis (Guenee) per plant recorded by T6 neem oil 2%, T7 pongamia oil 2% and T5 mahua oil 2% which were statistically at par with throughout the observation. The T6 neem oil 2% and T7 pongamia oil 2% recorded as best treatments over rest of the treatments. The grain yield in the treatment significantly highest grain yield @3730.00 kg and 3627.63 kg recorded by T6 Neem oil 2% and T7 Pongamia oil 2% followed by T5 Mahuva oil recorded yield @ 3283.30kg. However, the chemical treatments viz., T3 Profenophos 50 EC @0.03% and T4 quinolphos 25 EC @ 0.05% recorded yield @ 2956.66 and 2936.00 kg/ha both at par with each other. Whereas untreated control recorded the lowest yield @2426.03 kg/ha.

Sub-Lethal Effects of Pirimiphos-Methyl Are Expressed to Different Levels in Wings of Three Stored-Product Coleopterans: A Geometric Morphometrics Investigation

Tenebrio molitor L. (Coleoptera: Tenebrionidae), Prostephanus truncatus (Horn), and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) are noxious insect pests of grains in storages. Pirimiphos-methyl is widely used to protect grains at the post-harvest stage. However, the sub-lethal impact of this active ingredient on the offspring of all three coleopterans remains unknown. Thus, mated females of each species were exposed separately to pirimiphos-methyl at short exposures (30 min, 3, 5, 8, 16, 24, and 36 h), where the elytra and hindwings of the adult progeny were analyzed with the geometric morphometrics method. Males and females of all species were incorporated into the analysis. The results revealed variability among species. Tenebrio molitor was the most sensitive among three species, displaying significant deformations in the elytra and hindwings. Males had more conspicuous morphological changes than females. Prostephanus truncatus hindwings exhibited deformities after 36 h of exposure to pirimiphos-methyl. In contrast, R. dominica offspring were not affected by pirimiphos-methyl. In light of our findings, organophosphorus insecticides may cause variable sub-lethal effects to stored-product insects. This issue may lead to different insecticidal treatments according to the targeted stored-product species.

Population dynamics of the leafhopper Jacobiasca lybica (Hemiptera: Cicadellidae) within vineyards and citrus orchards of Morocco

The population dynamics of Jacobiasca lybica were monitored in different grapevines cultivars, citrus trees, and windbreak trees and the planning of insecticide treatments based on the recorded degree days (DD) was investigated. The study was conducted in Berkane province of Morocco during 2019, 2020 and 2021, using five yellow sticky traps for each experimental unit that were collected weekly for identification and counting of leafhopper adults. The leafhopper population fluctuated within vineyards, citrus trees and windbreak trees according to temperature recorded where three to seven overlapping peaks of adult flight were observed until September in 2019 and 2021, while a total of ten generations were predicted according to DD until December in 2020. The incidence started to appear clearly on Carignan during July of each year, but on Syrah it appeared only at August to reach 100% of incidence. These periods coincide with the nymph peaks that were higher on Carignan than Syrah. The leafhopper preference to Acacia trees over Cypress trees was observed for all years. Finally, the leafhopper population was decreased after the insecticides applications that were planned mostly after the week following the achieved DD. This technique is discussed as a promising technique to apply the control measures at the correct time.

The Pampa del Indio project: District-wide quasi-elimination of Triatoma infestans after a 9-year intervention program in the Argentine Chaco.

The elimination of Triatoma infestans, the main domestic vector of Trypanosoma cruzi, is lagging behind expectations in the Gran Chaco region. We implemented an insecticide-based intervention program and assessed its long-term effects on house infestation and bug abundance in a resource-constrained municipality (Pampa del Indio, northeastern Argentina) inhabited by creole and the Qom indigenous people (2007-2016). Key questions were whether district-wide data integration revealed patterns concealed at lower spatial levels; to what extent preintervention infestation and pyrethroid resistance challenged the effectiveness of insecticide-based control efforts, and how much control effort was needed to meet defined targets. Supervised vector control teams i) georeferenced every housing unit at baseline (1,546); ii) evaluated house infestation using timed-manual searches with a dislodging aerosol across four rural areas designated for district-wide scaling up; iii) sprayed with pyrethroid insecticide 92.7% of all houses; iv) periodically monitored infestation and promoted householder-based surveillance, and v) selectively sprayed the infested houses, totaling 1,823 insecticide treatments throughout the program. Baseline house infestation (mean, 26.8%; range, 14.4-41.4%) and bug abundance plummeted over the first year postintervention (YPI). Timed searches at baseline detected 61.4-88.0% of apparent infestations revealed by any of the methods used. Housing dynamics varied widely among areas and between Qom and creole households. Preintervention triatomine abundance and the cumulative frequency of insecticide treatments were spatially aggregated in three large clusters overlapping with pyrethroid resistance, which ranged from susceptible to high. Persistent foci were suppressed with malathion. Aggregation occurred mainly at house compound or village levels. Preintervention domestic infestation and abundance were much greater in Qom than in creole households, whereas the reverse was recorded in peridomestic habitats. House infestation, rare (1.9-3.7%) over 2-6 YPI, averaged 0.66% (95% confidence interval, 0.28-1.29%) at endpoint. Upscale integration revealed multiple coupled heterogeneities (spatial, sociodemographic and biological) that reflect large inequalities, hamper control efforts, and provide opportunities for targeted, sustainable disease control. High-coverage, professional insecticide spraying combined with systematic surveillance-and-response were essential ingredients to achieve the quasi-elimination of T. infestans within 5 YPI and concomitant transmission blockage despite various structural threats and constraints.

Integrated approach using insecticides in combination with reflective plastic mulch for the management of pepper weevil, Anthonomus eugenii (Coleoptera: Curculionidae).

Pepper weevil, Anthonomus eugenii Cano, is a serious pest of peppers (Capsicum annuum) in the United States and worldwide. This study evaluated the combined effect of insecticides (thiamethoxam and oxamyl) and reflective mulches (reflective silver on white and reflective silver on black) on pepper weevil suppression and yield increase. This study was conducted under field conditions in Homestead, FL, during the fall 2020, spring 2021, and 2022 growing seasons. The study consists of 2 mulch treatments as the main plots (reflective "silver on white," "white on black") and a bare ground with "no mulch" treatment in fall 2020 and spring 2021, and in spring 2022 with an additional treatment of reflective "silver on black" mulch. We hypothesized that jalapeño pepper grown on either reflective "silver on black" or "silver on white" plastic mulches would have fewer pepper weevil adults, fewer pepper weevil infested fruits, and higher yield than those grown on "white on black" plastic mulch or bare soil. Overall, the number of pepper weevil adults on plants and infested fruits was lower in the fall season compared to the spring season. In the fall 2020 season, the number of adults was not significantly different regardless of insecticide treatment and mulch type. However, infested fruits were higher on the untreated control plots than the treated plots in Fall 2020. Marketable yield was not significantly different among insecticide treatment on the "white on black" and reflective "silver on white" mulches. However, thiamethoxam treated plots had significantly higher yield than on the rest of the treatment on the bare soil with "no mulch." The number of adults was higher in the untreated control plot than the treated plots in spring 2021. The number of infested fallen fruits was not significantly different. However, marketable yield was significantly different among treatments on the "white on black" and reflective "silver on white" mulches in 2021. The treated plots on the reflective "silver on white" mulch produced significantly higher yield than the untreated control plots in 2022. The result of this study suggests that growing jalapeño peppers on reflective plastic mulch ("silver on white") in integration with thiamethoxam or oxamyl has the potential in reducing pepper weevil adult population and increasing yield of jalapeño pepper.

Identification and validation of reference genes for normalization of gene expression analysis using qRT-PCR in Megalurothrips usitatus (thysanoptera: thripidae).

Introduction: Gene expression analysis by reverse transcription quantitative polymerase chain reaction (qRT-PCR) has been widely used in research including insects. The selection of appropriate reference genes is the key to obtaining accurate and reliable results from qRT-PCR. However, studies on the expression stability of reference genes in Megalurothrips usitatus remain lacking. Methods: In this study, qRT-PCR was used to analyze the expression stability of candidate reference genes in M. usitatus. The expression levels of six candidate reference gene transcription of M. usitatus were analyzed. GeNorm, NormFinder, BestKeeper, and ΔCt were used to analyze the expression stability of M. usitatus treated with biological factors (developmental period treatment) and abiotic factors (light, temperature, insecticide treatment, respectively). Comprehensive stability ranking of candidate reference genes was recommended by RefFinder. Results and Discussion: Results showed that ribosomal protein S (RPS) was the most suitable expression in insecticide treatment. Ribosomal protein L (RPL) was the most suitable expression at developmental stage and light treatment, whereas elongation factor was the most suitable expression in temperature treatment. RefFinder was used to comprehensively analyze the above four treatments, and the results showed that RPL and actin (ACT) showed high stability in each treatment. Therefore, this study identified these two genes as reference genes in the qRT-PCR analysis of different treatment conditions of M. usitatus. Ourfindings will be beneficial for improving the accuracy of qRT-PCR analysis for future functional analysis of the target gene expression in M. usitatus.

Curative efficacy of entomopathogenic nematodes against white grubs in honeysuckle fields

Root-feeding white grubs are one of the most serious pests of honeysuckle trees (Lonicera japonica) in China, directly damaging their roots and facilitating infection by soil pathogens. Entomopathogenic nematodes (EPNs) are considered as potential control agents against soil-dwelling insect pests. This study aimed to identify effective EPN species against white grubs through bioassay and field experiments. Among the EPN species screened against Holotrichia oblita under laboratory conditions, Steinernema feltiae and Heterorhabditis indica had low virulence, while S. longicaudum, S. glaseri, and H. bacteriophora applied at a rate of 400 IJs/larva caused a higher corrected mortality (80.00 ± 5.77%), which screened them as good candidates for future applications. The field experiments showed that both S. longicaudum and H. bacteriophora were approximately as effective in reducing white grubs as the insecticide phoxim, whereas S. glaseri caused a significantly lower reduction compared with these two EPNs and phoxim. Plant mortalities obtained from S. longicaudum, H. bacteriophora and the insecticide treatment plots were significantly lower than those observed in the water-treated control plots. All EPNs examined could establish well in the treated honeysuckle fields for 42 d, confirmed by Tenebrio molitar larvae baiting technique. Our findings suggest that EPNs could provide curative efficacy against white grubs and significantly reduce plant death in honeysuckle fields.

Insecticidal Potential of Homemade Neem Extract Against Jassid <i>Amrasca biguttula biguttula</i> (Ishida) Infesting Okra

Field experiments were conducted during 2020 and 2021 to evaluate the efficacy of homemade neem extract @ 3000, 4000 and 5000 ml along with standard insecticide imidacloprid 17.8 SL @ 100 ml (standard check)/ ha against jassid Amrasca biguttula biguttula in okra at the Punjab Agricultural University Regional Research Station, Gurdaspur and farmer’s field at Marianwala (Batala), Punjab. The results revealed that all insecticidal treatments were very effective. Imidacloprid 17.8SL proved superior and gave maximum fruit yield followed by higher and median dose of homemade neem extract. The highest cost benefit ratio (Rs. 1: 75.74) was achieved with highest dose of homemade neem extract and closely followed by imidacloprid 17.8 SL (Rs. 1: 50.74). These were also found very safe towards predators (spider and coccinellid)

Evaluating Efficacy and Chemical Concentrations of Commonly Used Insecticides Targeting Tarnished Plant Bug in Mid-South Cotton

Studies were conducted from 2017 to 2021 at nine locations across Arkansas, Louisiana, Mississippi, and Tennessee to evaluate efficacy, residual control, and effective chemical concentrations of commonly used insecticides targeting tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), nymphs in Mid-South cotton. Foliar applications of imidacloprid, flonicamid, thiamethoxam, oxamyl, dicrotophos, acephate, novaluron, and sulfoxaflor were applied at locally recommended rates. Plots were sampled for nymphs at 4, 7, and 10 d after treatments (DAT), and leaves were analyzed for concentration of active ingredients from plots located in one site in 2021 at 4, 7, 10, and 14 DAT. Across all sampling dates, insecticide treatments reduced nymph infestations compared to untreated control, except for imidacloprid at 10 DAT. All insecticide treatments resulted in higher lint yields compared to untreated control. Overall, sulfoxaflor, novaluron, and acephate offered the best control of nymphs and provided the greatest yield protection among treatments. Moderate control was achieved with thiamethoxam, oxamyl, and dicrotophos. Imidacloprid and flonicamid resulted in less control. Concentrations of flonicamid, thiamethoxam, dicrotophos, acephate, and novaluron persisted up to 14 DAT in leaves. Imidacloprid and oxamyl were not detected at 7, 10, or 14 DAT, and sulfoxaflor was not detected at 14 DAT in leaves. In these studies, control of tarnished plant bug nymphs never exceeded 75% regardless of insecticide or sampling date. The moderate efficacy and short residual control shown in these studies explain why multiple insecticide applications within short intervals are needed to manage heavy tarnished plant bug populations

Efficacy of four systemic insecticides for reducing Nantucket pine tip moth (Rhyaciona frustrana) (Lepidoptera: Tortricidae) infestation levels and improving growth metrics in loblolly pines.

The Nantucket pine tip moth (NPTM) (Rhyacionia frustrana Comstock) is a native, regeneration pest of young loblolly pines (Pinus taeda L.), causing shoot dieback, tree deformity, and growth and volume declines. Soil applications of systemic insecticides may be an effective strategy to suppress NPTM populations. The study objective was to assess the efficacy of four systemic insecticide treatments (chlorantraniliprole, dinotefuran, fipronil, and imidacloprid) for two growing seasons in outplanted bareroot and containerized seedling trials. Response variables included NPTM infestation rates, along with tree height, groundline diameter, volume index, and stem form. Infestation rates significantly decreased for each systemic insecticide treatment during the first year compared to controls, although dinotefuran and imidacloprid provided season-long control in one trial. Chlorantraniliprole reduced NPTM infestation rates for two growing seasons in both trials. While imidacloprid treatments did not alter growth metrics except for one comparison, fipronil and dinotefuran treatments improved several growth metrics. Chlorantraniliprole consistently improved growth metrics throughout the study.

Can Insects Assess Environmental Risk? Movement Responses and Nymph Emergence in Response to Insecticides

In natural habitats, there is a strong evolutionary selection pressure on herbivorous insects to avoid danger and choose suitable host plants. Similar selection pressures may drive movement and choices of oviposition hosts by herbivorous insects living in agricultural cropping systems, in which insecticides are often used. In this study, we quantified movement responses and nymph emergence (collectively referred to as bio-responses) of western-tarnished plant bug (Lygus hesperus Knight (Hemiptera: Miridae)) individuals when exposed to environments associated with a perceived “risk” (experimental insecticide treatments and their corresponding controls). We introduce a novel analytical approach in which treatments (risk environments) are ranked in ascending order based on bio-responses (movement or nymph emergence). Consequently, linear regression coefficients were generated and used to interpret bio-responses of Lygus individuals in different life stages to risk environments. Initially, we predicted movement by Lygus individuals to be positively associated with environmental risk and nymph emergence to be negatively associated with environmental risk. Overall, based on a comprehensive combination of no- and two-choice bioassays, we found that: (1) In no-choice bioassays, movement parameters (both total distance moved and movement percentage) by all three life stages were lowest in low-risk environments and highest when Lygus individuals were exposed to either malathion or Grandevo. Accordingly, environments involving malathion or Grandevo were considered high-risk. (2) No-choice movement bioassays also revealed that Lygus males moved significantly more (based on comparison of regression intercepts) than other life stages, and that they responded significantly more (based on comparison of regression slopes) than conspecific females and nymphs. (3) In two-choice movement bioassays, neem elicited the most consistent movement responses by Lygus individuals, and adult life stages showed the strongest response. Two-choice movement bioassays also revealed that Lygus adults, compared to nymphs, were more likely to spend time in low-risk areas of the test arenas. (4) Nymph emergence was markedly lower in no-choice compared to two-choice bioassays, and in two-choice bioassays, Grandevo and malathion elicited especially biased nymph emergence from low-risk beans. To our knowledge, this is the first study in which movement bioassays have been used to quantify and characterize behavioral responses by Lygus life stages to environments associated with varying degrees of risk. The novel analytical approach presented in this study provides a high degree of complementarity to more traditional performance-testing methods used to evaluate responses to insecticides. Furthermore, we believe that this analytical approach can be of considerable relevance to studies of animal phenomics and behavioral studies of animals more broadly, in which adaptation and fitness parameters are examined in response to environmental risk and heterogeneity.