Insecticide Tests Research Articles

Assessing the Compatibility of Streptomyces saraceticus With Pesticides and the Efficacy in Controlling Root‐Knot Nematode

ABSTRACTStreptomyces saraceticus strain 31 (SS31) exhibits antagonistic activities against a variety of phytopathogenic bacteria, fungi and nematodes. In our effort to integrate SS31 into an effective pest management programme for controlling plant pathogens, we assessed the toxicities of 74 pesticides commonly employed in agricultural production on SS31 using paper disc assays. Most of the test insecticides, acaricides, nematicides and plant growth regulators showed no antagonistic effects towards SS31. However, all six tested herbicides, glyphosate, paraquat, glufosinate‐ammonium, quizalofop‐ethyl, pendimthalin and butralin exerted strong inhibitory effects on SS31. Among the 42 tested fungicides, half of them, including acid amides, strobilurins, carbamates, antibiotics and morphine displayed no detrimental effects on SS31. Notably, copper‐based fungicides demonstrated high toxicity to SS31. Although chlorothalonil and thiophanate methyl + streptomycin displayed inhibitory effects on SS31, applying these pesticides with SS31 in pot tests resulted in a lower Meloidogyne incognita galling index compared with the mock control under greenhouse conditions. Additionally, applying SS31 with carbofuran or ethoprop effectively controlled M. incognita. These findings can provide strategies to refine application timing and enhance the beneficial effects of SS31.

Essential oil of endemic Centaurea paphlagonica: chemical composition, insecticidal, enzyme inhibitory activities and molecular docking approach

The key objective of this study was to determine the chemical composition, insecticidal and butyrylcholinesterase (BChE) inhibitory activities of crude essential oils (CEO) extracted from the stem-leaf parts of the endemic Centaurea paphlagonica plant via steam distillation, as well as its chromatography-based fractions for the first time. According to GC-MS analysis, eighty-five compounds were identified representing 98.49% of the total essential oil. β-Eudesmol (15.17%), phytol (8.69%), and spathulenol (8.03%) were determined as the main components. The CEO demonstrated a remarkably insecticidal activity against S. granarius and R. dominica insects, ranging from 98.35% to 100%, while achieving a 50% against T. confusum at a 10% concentration. The silica gel-based fractionation of CEO resulted in four qualitatively different fractions (CEO-F1 to F4). The CEO-F2, predominantly comprised of β-eudesmol and spathulenol, exhibited superior activity compared to CEO across all tested insects. In addition, the inhibitory activity of BChE, which causes death in insects by altering nervous system activities, was assessed. BChE inhibition activity of CEO and CEO-F2 was determined as IC50=346.57 μg/mL and 96.02 μg/mL, respectively, supporting the insecticidal activity tests and molecular docking studies. The volatile oil obtained from C. paphlagonica can be considered a potential natural source to combat storage product pests, with its significant natural volatile compounds.

Oriented synthesis and insecticidal activities of novel meta‐diamide scaffolds incorporating with 1,2,4‐triazole moiety

AbstractIn an effort to discover a new insecticide, we designed and synthesized a series of novel meta‐diamide compounds containing 1,2,4‐triazole with cyproflanilide as a lead compound. All the compounds were characterized by 1H NMR, 13C NMR, and HR‐MS. Both Plutella xylostella and Mythimna separata were tested for their insecticidal activity at 200 mg/L (P. xylostella: 0%–100%; M. separata: 0%–100%), 20 mg/L (P. xylostella: 0%–97%; M. separata: 0%–100%), and 2 mg/L (P. xylostella: 0%–97%; M. separata: 0%–100%), while Aphis craccivora was tested for its insecticidal activity at 400 mg/L (A. craccivora: 0%–36%). Further studies are needed to investigate the insecticidal activity of A. craccivora. Preliminary bioactivity results showed that most of the compounds had good insecticidal activity at 200 mg/L against P. xylostella and M. separata. Especially, the compound 7p, N‐(cyclopropylmethyl)‐N‐(5‐((2,6‐dibromo‐4‐(perfluoropropan‐2‐yl)phenyl) carbamoyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)‐6‐(trifluoromethyl)nicotinamide (7p), showed good insecticidal activity at even lower doses of 2 mg/L (P. xylostella: 97%; M. separata: 100%), which was equivalent to that of the lead compound cyproflanilide (P. xylostella: 100%; M. separata: 100%), as well as significantly better than the two known compounds Ia (P. xylostella: 97%; M. separata: 0%) and Ib (P. xylostella: 60%; M. separata: 0%). Preliminary structure–activity relationship was also discussed based on insecticidal tests. The results indicate that meta‐diamide compounds containing 1,2,4‐triazole can be developed as novel insecticides.

Activities and Kinetic Parameters of Carboxylesterases in Model Insects depending on a Substrate of the Enzyme

House flies Musca domestica L. (Diptera: Muscidae) serve as a common model organism for testing of insecticides and research of insecticidal resistance mechanisms in insects. One of important stages is to assess of detoxifying enzyme activities including carboxylesterase activities (CarE). In this study, we compared specific activities and kinetic parameters (Vmax and Km) of CarE in adults M. domestica of two laboratory strains (TY, UF) depending on the enzymatic substrate used. The specific CarE activities towards α- and β-naphthyl acetate (α-NA and β-NA) were similar in both males and females of the TY strain. In males of the UF strain, the value of the specific and the maximal velocity (Vmax) of β-NA hydrolysis was 1.90- and 1.57-fold respectively less than that of α-NA; this difference was not observed in females of the same strain. Some characteristics of CarE varied depending on sex of insects when p-nitrophenyl acetate was used as an enzymatic substrate. In particular, the specific activity was 1.62-fold less in males of the UF strain compared to this value in females. The activity and main kinetic parameters of CarE towards α-NA not differed statistically significant depending on sex and the strains. Based on the results obtained we suggest that α-naphthyl acetate is the preferred substrate to evaluate the CarE enzymatic activity in the model insect M. domestica of different strains.

Evaluation f the Insecticidal Activity of Nerium Oleander and Artemisia Campestris Powder and Extract on Wheat Insect Pests

Objective: The study aimed to evaluate the insecticidal potential of powders and methanolic extracts of two plants of the Lamiaceae and Apocynaceae families spontaneously growing in the region of Tiaret. Method: Insecticide tests were carried out in the laboratory using the Direct Contact Method. Results and Discussion: The obtained results showed that Nerium oleander and Artemisia campestris powders have remarkable insecticidal properties. N oleander powders induced 100% mortality in adults and up to 80% mortality in Tribolium castaneum larvae at a dose of 0.5g, after 7 days of exposure. Adults of Tribolium confusum showed some resistance to the powders of both plants, with an optimum mortality rate equal to 50% for adults. Larvae of both species were found to be sensitive to N. oleander powder with a mortality rate ranging from80to 90%. As for the powder of A. campestris, adults of T. castaneum were more sensitive than those of T.confusum, with adults’mortality rate equal to 100%. The methanolic extracts of both plants showed a very remarkable efficacy against the larvae of both species as well as the adults of T. castaneum with a mortality rate equal to 100%, after 7 days of treatment at different concentrations. Research Implications: Algeria has an abundance and diversity of flora that could provide new sources of compounds of plant origin with phytopharmaceutical properties, these results allow us to affirm that powders and methanolic extracts, of the studied plants, can be used for industrial application in the production of bio-insecticides. Originality/Value: This work could provide alternative or complementary solutions to the use of synthetic organic pesticides to protect stored beans. The development of bio-insecticides derived from plant extracts and the selection of varieties resistant to this pest are part of sustainable agriculture and development.

A Comparative Study on the Antioxidant and Insecticidal Activities of <i>Eucalyptus camaldulensis </i>Essential Oil and Hydrosol

The study investigates the hydrosol of <i>Eucalyptus camaldulensis</i> to assess its value and potential applications within the essential oil (EO) industry. Following steam distillation of <i>E. camaldulensis</i> leaves to extract essential oil, the resulting hydrosol underwent liquid-liquid extraction to yield a secondary essential oil (SEO). Comparative chemical analysis was performed using GC/MS. Comparative chemical analysis of the SEO and EO revealed distinct compositions, with 24 compounds identified in the SEO compared to 41 in the EO. Oxygenated compounds predominated in the SEO while non-oxygenated compounds were the most abundant in the EO (63.61%). Eucalyptol emerged as the primary constituent in both, with higher concentrations observed in the SEO (60.41%) than in the EO (28.53%). Additionally, antioxidant activity assessed using the DPPH assay demonstrated significant radical reduction in the SEO compared to the EO. In insecticidal tests targeting Callosobruchus maculatus, the SEO exhibited pronounced toxicity, with an IC<sub>50</sub> value lower than that of the EO. This study showed the abundance of oxygenated compounds in <i>E. camaldulensis</i> hydrosol compared to pure essential oil, suggesting its potential as an antioxidant agent and for integrated pest management in agriculture. The research highlights the value of hydrosols in the EO industry and their potential applications in natural product formulations and pest control strategies.

Morphological, Molecular Identification and Virulence of Entomopathogenic Fungi Isolated From Dendroctonus micans (Kugelann,1794) (Coleoptera: Curculionidae)

In this study, to determine an effective fungal agent against Dendroctonus micans (Kugelann, 1794) (Coleoptera: Curculionidae), which causes significant economic losses in forested areas, Picea orientalis (L.) Link in Artvin between 2021-2022. Dendroctonus micans larvae and adults were collected from the trees, and 18 fungi were isolated from larvae and adult insects. Morphological (infection type, colony morphology, spore form) and molecular (ITS1-5.8S ITS2 gene region) characterization determined that the isolates were Metarhizium anisopliae (Metschn.) Sorokin, 1883 (Hypocreales: Clavicipitaceae), M. robertsii, M. pinghaense and Clonostachys rosea Samuels & Rossman, 1999 (Hypocreales: Bionectriaceae). Isolates M. robertsii (OZM4) and M. pinhaense (OZM9) have been isolated from this pest for the first time. As a result of insecticidal activity tests performed on D. micans larvae and adults of 1x107spore/ml spore suspension, the larvae, M. anisopliae (OZM2), showed a mortality rate of 92% within 7 days and adults mortality was determined 100% at the end of the experiment, and mycosis rates were found to be consistent with mortality rates. These results show that isolates with high virulence are promising in microbial and integrated control applications against important forest pests.

Larvicidal activity of Acacia nilotica extracts against Culex pipiens and their suggested mode of action by molecular simulation docking

Mosquitoes are one of the deadliest and most hazardous animals on Earth, where they transmit several diseases that kill millions of people annually. There is an ongoing search almost everywhere in the world for more effective and contemporary ways to control mosquitoes other than pesticides. Phytochemicals are affordable, biodegradable biological agents that specialize in eliminating pests that represent a risk to public health. The effectiveness of Acacia nilotica methanol and aqueous leaf extracts against 4th instar larvae was evaluated. The results revealed that the methanol extract of A. nilotica had a noticeable influence on the mortality rate of mosquito larvae, especially at high concentrations. Not only did the mortality rate rise significantly, but the hatching of the mosquito eggs was potentially suppressed.Terpenes, fatty acids, esters, glycosides, pyrrolidine alkane, piperazine, and phenols were the most prevalent components in the methanol extract, while the aqueous extract of A. nilotica exclusively showed the presence of fatty acids. The insecticidal susceptibility tests of both aqueous and alcoholic extract of A. nilotica confirmed that the Acacia plant could serves as a secure and efficient substitute for chemical pesticides because of its promising effect on killing larvae and egg hatching delaying addition to their safety as one of the natural pesticides. Molecular docking study was performed using one of the crucial and life-controlling protein targets, fatty acid binding protein (FABP) and the most active ingredients as testing ligands to describe their binding ability. Most of the structurally related compounds to the co-crystallized ligand, OLA, like hexadecanoic acid furnished high binding affinity to the target protein with very strong and stable intermolecular hydrogen bonding and this is quite similar to OLA itself. Some other structural non-related compounds revealed extraordinarily strong binding abilities like Methoxy phenyl piperazine. Most of the binding reactivities of the majortested structures are due to high structure similarity between the positive control, OLA, and tested compounds. Such structure similarity reinforced with the binding abilities of some detected compounds in the A. nilotica extract could present a reasonable interpretation for its insecticidal activity via deactivating the FABP protein. The FABP4 enzyme inhibition activity was assessed for of both methanolic and aqueous of acacia plant extract and the inhibition results of methanol extract depicted noticeable potency if compared to orlistat, with half-maximal inhibitory concentration (IC50) of 0.681, and 0.535 µg/ml, respectively.

Bio-efficacy of essential oils of <i>Eryngium foetidum</i> L. and <i>Plectranthus amboinicus</i> (Lour.) Spreng against <i>Anopheles gambiae</i> Giles


 Malaria and lymphatic filariasis transmitted by female Anopheles mosquitoes remain health challenges in tropical Africa. Resistance by vectors to synthetic insecticides limits control efforts. This study evaluated efficacy of essential oils of Eryngium foetidum and Plectranthus amboinicus against Anopheles gambiae. Test oils were obtained by hydro-distillation using Clevenger apparatus. From 1 mL stock solution, 31.25, 62.50, 125 and 250 and 500 μL/mL concentrations of E. foetidum and P. amboinicus oils were prepared using serial-dilution with tween 80 as diluent. Each concentration had eighty adult mosquitoes exposed. Results of knockdown and insecticidal tests after 30 and 60 minutes respectively revealed higher susceptibility of An. gambiae to E. foetidum. Eryngium foetidum (250μL/mL) elicited 100% knockdown after 20 minutes. In the insecticidal test, the same concentration resulted in 100% mortality at 40 minutes. Same effect was observed for 500 μL/mL of P. amboinicus oil at 25 and 60 minutes. From Probit analysis, KD50 values were 66.793 and 251.350 μL/mL for E. foetidum and P. amboinicus respectively. Values for LC50 were 85.818 and 428.663 μL/mL for E. foetidum and P. amboinicus respectively. Results demonstrate that E. foetidum oil holds promise as control agent against An. gambiae. Plectranthus amboinicus oil did not demonstrate appreciable efficacy.

Photocatalytically active Ag-doped TiO2 coatings developed by plasma electrolytic oxidation in the presence of colloidal Ag nanoparticles

The plasma electrolytic oxidation process of Ti foil in the presence of a colloidal solution of Ag nanoparticles was used for the synthesis of exceptionally photocatalytically active Ag-doped TiO2 coatings. UV–Vis absorption spectroscopy was applied to follow the changes in the surface plasmon resonance band of the Ag nanoparticles as a function of the Ag:PO43− ratio in a phosphate-based electrolyte solution. Transmission electron microscopy revealed the size of the Ag nanoparticles in the range of 3–12 nm. The XRD patterns of the Ag-doped TiO2 coatings confirmed the crystalline anatase TiO2 phase regardless of the dopant concentration and without metallic Ag or crystalline Ag oxide forms. The typical porous morphology of the Ag–TiO2 coatings was observed by scanning electron microscopy. A significantly improved photocatalytic activity of the Ag–TiO2 coatings in the degradation process of the insecticide lindane (gamma isomer of benzene hexachloride) and test molecule methyl orange compared to pure TiO2 was determined using the GC technique. The degradation efficiency of Ag-doped TiO2 coatings is higher for lindane than for methyl orange.

Impact of a spatial repellent intervention on Anopheles kdr insecticide resistance allele in Sumba, Indonesia

BackgroundThe emergence of insecticide resistance and outdoor transmission in malaria-endemic areas underlines the urgent need to develop innovative tools, such as spatial repellents (SR), that may circumvent this residual transmission. With limited options for effective insecticides, regular resistance monitoring is warranted for selecting and using appropriate tools. This study evaluates the pyrethroid knockdown resistance (kdr) allele before and after implementing a transfluthrin-based spatial repellent (SR) intervention in placebo-treated clusters.MethodsThis study looks at the frequency distribution of the kdr allele in Sumba Island from June 2015 to August 2018. Insecticide susceptibility tests were carried out on female Anopheles sp. aged 3–5 days against permethrin 21.5 μg/ml, deltamethrin 12.5 μg/ml, and transfluthrin 10 μg/ml using CDC bottle assay. PCR sequencing of representative samples from adult mosquito collections and insecticide tests revealed the presence of kdr mutations (L1014F and L1014S) in the VGSC gene.ResultsA total of 12 Anopheles species, Anopheles tesselatus, Anopheles. aconitus, Anopheles barbirostris, Anopheles kochi, Anopheles annularis, Anopheles maculatus, Anopheles sundaicus, Anopheles flavirostris, Anopheles balabacensis, Anopheles indefinitus, Anopheles subpictus, and Anopheles vagus were analysed. Anopheles vagus and An. sundaicus predominated in the larval populations. Susceptibility assays for all insecticides identified fully susceptible phenotypes in all species examined. Anopheles increasing frequency of kdr mutant alleles during the 3 year SR deployment was observed in both SR-treated and placebo areas, a statistically significant increase occurred in each arm. However, it is unclear how significant SR is in causing the increase in mutant alleles. The L1014S, knockdown resistance east type (kdr-e) allele was detected for the first time among the mosquito samples in this study. The L1014F, knockdown resistance west type (kdr-w) allele and heteroduplex form (wild-type—mutant) were found in almost all Anopheles species examined, including An. vagus, An. aconitus, An. subpictus, An. tesselatus, An. annularis, An. flavirostris and An. sundaicus.ConclusionThe presence of fully susceptible phenotypes over time, along with an increase in the frequency distribution of the L1014F/S mutations post-intervention, suggest drivers of resistance external to the study, including pyrethroid use in agriculture and long-lasting insecticidal nets (LLINs). However, this does not negate possible SR impacts that support resistance. More studies that enable the comprehension of possible SR-based drivers of resistance in mosquitoes need to be conducted.

Mosquito Control Strategies and Insecticide Resistance of the Malaria Vector in Urbanized Land Use Types in Suame Municipality, Ghana.

Modified landscapes could create breeding habitats for mosquitoes and affect their community structure and susceptibility with implications for their management. Hence, in this study, household mosquito control methods in two urbanized landscapes; industrial and residential human settlements, in Ghana and insecticide susceptibility of the inhabiting Anopheles populations were assessed. Household knowledge and usage pattern of mosquito control methods in the modified landscapes were obtained using a questionnaire. Female adult Anopheles mosquitoes were also subjected to susceptibility tests using mosquito coils (0.08% meperfluthrin, 0.03% dimefluthrin, and 0.3% transfluthrin) and World Health Organization (WHO) insecticide test papers (0.05% deltamethrin, 4% DDT, 0.1% bendiocarb, 0.25% pirimiphos-methyl, and 5% malathion). Although insecticide-treated nets and aerosols were used for mosquito control, mosquito coils were the most common and widely preferred household method. The Anopheles mosquitoes were resistant to all the insecticides (mosquito coils and WHO test papers) except pirimiphos-methyl. Land use type did not affect insecticide resistance, but the insecticide type did. The findings indicate the effect of household insecticide usage practices on local mosquito populations and their implications for effective vector management and disease control in modified landscapes.

Chemical Composition and Toxic Effect of Plant Essential Oil Against Sitophilus Oryzae(L) (Insecta: Coleoptera:Curculionidae)

The aerial parts of Ruta montana were collected from two different locations in Algeria (Berrouaghia and HamamMelouane). A hydrodistillation was conducted and the resulting volatile oil was analyzed by Gas chromatography coupled with Mass Spectrometry (GC/MS). The results showed that the best yield in essential oil was obtained in full bloom (0.98%) from the region of Berrouaghia which was higher than the yield of the ecotype gathered in Hammam Melouane (0.82 %). The main predominant component of R.montana collected from Berroughia and HamamMelouane is 2-Undecanone (C11H22O); (59.34%) and (49.39%) respectively. The insecticidal test by in vitro contact assay showed a significant mortality of Sitophilus oryzae traited by R. Montana essential oil (EO). The results of this study showed that the toxicity of the R. montana oil vary with increasing concentration of applied doses on one hand, and a relatively gradual efficiency versus time, which results in improved efficiency on the other hand.

CONTROL OF THE OF MAIN PESTS OF WINTER OILSEED RAPE IN THE CONDITIONS OF VINNYTSIA REGION

This article highlights the issue of improved and substantiated elements of the winter oilseed rape protection system against main pests in the Vinnitsa region, which is based on clarification of the species composition of phytophagy in winter oilseed rape, their harmfulness and limiting their numbers when applying seed treatment with insecticides and poisoners. spraying crops with drugs during the growing season of the crop. The species composition of the harmful entomofauna of winter oilseed rape was clarified and 22 species of insects belonging to 6 orders and 16 families were identified. The largest species diversity is characterized by the number of Coleoptera, the share of species of which was 60,2% of the total. The effectiveness of modern insecticides of poisoners against pests of winter oilseed rape and optimized methods of their application were evaluated. It has been established that the highest technical efficiency of insecticide poisoners is noted in versions with poisoners with mixtures of Force 200 SC + Cruiser 350 FS, consumption rate of 1,0+2,0 l/t. and Cruiser 350 FS, w.s.c. at the full consumption rate of 4,0 l/t is a highly effective method of controlling the number of cruciferous fleas. Initial efficiency during the first three days after emergence was 92,0% and 90,5%. During the growing season of winter rape during the testing of insecticides, the highest technical efficiency – 93,3% for spraying rape seedlings against cruciferous fleas was shown by Confidor 20%, w.s.c. Confidor, 20% of the national capital, it provided technical efficiency at the level of 95,3%. This ensured a yield of 3.46 t/ha, and the yield increase was conventionally 0,53 t/ha of the crop.

Analysis of Potential Hazards Using the HIRADC Approach and Methods Job Safety Analysis on The Practical Process at The Department of Environmental Health

The Physics, Industrial Sanitation, and Occupational Safety Laboratory, also known to be the Health Department's Workshop Environment at the Ministry of Health Jakarta II Health Polytechnic, is part of the laboratory standards established through the Decree of the Minister of Health Number: HK.03.05/IV/14354.I/2010 concerning Health Personnel Education Laboratory Standards. To keep up with service standards or Standard Operating Procedures (SOP) in a laboratory and follow the Occupational Health and Safety management system following PP No. 50 of 2012 concerning the Implementation of Occupational Safety and Health Management Systems, the supporting facilities and infrastructure therefore require more effective and efficient attention. The objective of this study is to implement the Job Safety Analysis (JSA) and the HIRADC method to evaluate potential health and safety hazards at the Jakarta II Health Polytechnic Workshop. The result based on analysis and discussion using the JSA approach of the risk level research at the Department of Environmental Health workshop showed that 11% had a high-risk level, 28% had a medium-risk level, and 61% had a low-risk level. The highest risk is in the practical work of making slabs and testing insecticides for open joints using fogging and insecticides. The control provided is based on a control hierarchy, and it entails providing enough complete PPE in accordance with the risk of hazard and supervising the use of PPE during preparation and until the practicum process is complete.

Efficacy Testing of Different Microbial and Insecticides against Armyworm in Dhading, Nepal

Available with the full text.

Residue dynamics and dietary risk assessment of new formulation of novaluron and lambda cyhalothrin on tomato.

Presence of residues on food commodities is major bottleneck of insecticide use under good agricultural practices (GAPs). The use of less persistent with two different mode of action insecticide is novel approach of getting maximum insect control without developing insecticide resistance. Novaluron, an insect growth disruptor and lambda cyhalothrin, a nerve poison has been used widely for the management of lepidopteran pests. Dissipation and consumer risk analysis studies were carried out on a new combination product of novaluron and lambda cyhalothrin are used for control insects of tomato at recommended standard dose of 71 + 14 g/ha and double dose of 142 + 28 g/ha of active ingredients. Extraction and cleanup of sample residues was done using QuEChERS technique and analyzed in GC-ECD. The residues of novaluron were dissipated within 10 to 15 days, and the residues of lambda cyhalothrin were at 7 to 10 days, both at the standard and double the standard dose, following a first order reaction kinetics. Analysis of risk and hazard quotient revealed that the test insecticides do not pose any dietary risk to consumer as TMDI < MPI and HQ < 1.

Insecticidal and repellent activities of Azadirachta indica A. (Juss) oil against fifth instar larvae and adults of Sahlbergella singularis (Hemiptera:Miridae)

Sahlbergella singularis is one of the insects that causes the most damage to cocoa trees in Togo. The management of this pest is mainly based on chemical control, with its negative consequences for human health and the environment. In order to find an alternative to the use of synthetic pesticides, the insecticidal and repellent activities of neem oil were tested in vitro on fifth instar larvae and adults of S. singularis. Larvae were collected from a cocoa plot. The fifth instar larvae were separated from the other stages. Some of the larvae were reared in the laboratory until adult emergence. The concentrations of neem oil used were 0.5, 1, 1.5, 2 and 2.5 µl.ml-1. Insecticidal tests were carried out by spraying the solutions directly onto the insects. The repellency test was carried out using the preferential zone method on filter paper. The results showed an increasing mortality rate with increasing concentrations of neem oil for both fifth instar larvae and adults. The calculated LC50’s for larvae and adults were 0.89 and 0.98 µl.ml-1 respectively. Neem oil had a weak repellent effect on both fifth instar larvae and adults, with average repellency rates of 23.60% and 28.8% respectively. These results show that neem oil can be an alternative to the use of synthetic pesticides in the control of S. singularis.

Insecticidal Resistance in &lt;i&gt;Helicoverpa armigera&lt;/i&gt; (Hubner) Infesting Chickpea

A laboratory experiment was conducted at Post Graduate Laboratory, Department of Agricultural Entomology, College of Agriculture, Latur, Maharashtra, India during 2017-18. Resistance to five test insecticides viz., chlorantraniliprole, cyantraniliprole, emamectin benzoate, indoxacarb and spinosad was investigated against H. armigera infesting chickpea from different locations of Western Maharashtra (Ahmednagar, Kolhapur, Nashik, Pune, Sangali, Satara and Solapur). Results revealed that, H. armigera infesting chickpea of Solapur recorded 7.00-fold resistance to indoxacarb 15.8% EC which was higher than other field populations H. armigera. The resistance ratios varied greatly among the populations and high resistance factor of indoxacarb 15.8% EC against all field populations of H. armigera infesting chickpea from all 7 locations revealed that development of decreased susceptibility to low level resistance against this insecticide whereas chlorantraniliprole 18.5% SC, cyantraniliprole 10.26% OD, emamectin benzoate 5% SG and spinosad 45% SC found to be toxic.

The Amphibian Short-Term Assay: Evaluation of a New Ecotoxicological Method for Amphibians Using Two Organophosphate Pesticides Commonly Found in Nature-Assessment of Behavioral Traits.

Neurotoxic pesticides are used worldwide to protect crops from insects; they are recognized to impact nontarget organisms that live in areas surrounded by treated crops. Many biochemical and cell-based solutions have been developed for testing insecticide neurotoxicity. Nevertheless, such solutions provide a partial assessment of the impact of neurotoxicity, neglecting important phenotypic components such as behavior. Behavior is the apical endpoint altered by neurotoxicity, and scientists are increasingly recommending including behavioral endpoints in available tests or developing new methods for assessing contaminant-induced behavioral changes. In the present study, we extended an existing protocol (the amphibian short-term assay) with a behavioral test. To this purpose, we developed a homemade device along with an open-source computing solution for tracking trajectories of Xenopus laevis tadpoles exposed to two organophosphates insecticides (OPIs), diazinon (DZN) and chlorpyrifos (CPF). The data resulting from the tracking were then analyzed, and the impact of exposure to DZN and CPF was tested on speed- and direction-related components. Our results demonstrate weak impacts of DZN on the behavioral components, while CPF demonstrated strong effects, notably on speed-related components. Our results also suggest a time-dependent alteration of behavior by CPF, with the highest impacts at day 6 and an absence of impact at day 8. Although only two OPIs were tested, we argue that our solution coupled with biochemical biomarkers is promising for testing the neurotoxicity of this pesticide group on amphibians. Environ Toxicol Chem 2023;00:1-12. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.