Efficacy Of Insecticides Research Articles

Repellency, Toxicity, and Chemical Composition of Plant Essential Oils from Myrtaceae against Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera Liviidae).

Diaphorina citri Kuwayama (D. citri) is one of the major pests in the citrus industry, which spreads Citrus Huanglongbing disease. It has developed resistance to chemical insecticides. Therefore, searching for greener solutions for pest management is critically important. The main aim of this study was to evaluate the repellent and insecticidal efficacy of essential oils (EOs) from four species of Myrtaceae plants: Psidium guajava (PG), Eucalyptus robusta (ER), Eucalyptus tereticornis (ET), and Baeckea frutescens (BF) against D. citri and to analyze their chemical compositions. GC-MS analysis was performed, and the results indicated that the EOs of PG, ER, ET, and BF were rich in terpenoids, ketones, esters, and alcohol compounds. The repellent rate of all four EOs showed that it decreased with exposure time but increased with the concentration of EOs from 80.50% to 100.00% after treating D. citri for 6 h with four EOs at 100% concentration and decreased to 67.71% to 85.49% after 24 h of exposure. Among the compounds from the EOs tested, eucalyptol had the strongest repellent activity, with a 24 h repellency rate of 100%. The contact toxicity bioassay results showed that all EOs have insecticidal toxicity to D. citri; the LC50 for nymphs was 36.47-93.15 mL/L, and for adults, it was 60.72-111.00 mL/L. These results show that when PG is used as the reference material, the ER, ET, and BF EOs have strong biological activity against D. citri, which provides a scientific basis for the further development of plant-derived agrochemicals.

Oebalus pugnax (Hemiptera: Pentatomidae) resistance to lambda-cyhalothrin in Texas and efficacy of 2 alternative insecticides in grain sorghum.

Along the Coastal Bend of Texas, the rice stink bug, Oebalus pugnax (F.), is a major pest of grain sorghum and rice that is primarily managed by insecticide applications. Reports of rice stink bug resistance to pyrethroids in Texas first surfaced in 2015 and continued to spread. To determine the status of pyrethroid resistance, rice stink bug populations across Texas and Louisiana were evaluated from 2021 to 2023. Mortality was assessed through glass vial exposures to eight concentrations (0, 0.03, 0.1, 0.3, 1, 3, 10, and 30 μg/vial) of a pyrethroid, lambda-cyhalothrin. The concentration of lambda-cyhalothrin required to kill 50% (LC50) of each population was estimated by probit analysis. Furthermore, the efficacy of insecticides, including lambda-cyhalothrin, dimethoate, and dinotefuran, were evaluated in field experiments conducted in 2021. Our results indicated that 14 of the 21 rice stink bug populations sampled were resistant to lambda-cyhalothrin, with LC50 values ranging from 42 to 1,600 times higher than a susceptible population. In the field trial, lambda-cyhalothrin did not control rice stink bugs. Dinotefuran provided excellent control of nymphs, but dimethoate provided greater control of adult rice stink bugs. To our knowledge, this is the first study to thoroughly evaluate the extent or geographic range of pyrethroid resistance in Texas for rice stink bugs.

Efficacy of Bioinsecticides, Synthetic Insecticides, Macro and Micronutrients for the Management of Onion Thrips, Thrips tabaci in Onion: a Field Trial

Efficacy of Bioinsecticides, Synthetic Insecticides, Macro and Micronutrients for the Management of Onion Thrips, Thrips tabaci in Onion: a Field Trial

In vitro larvicidal efficacy of Lantanacamara essential oil and its nanoemulsion and enzyme inhibition kinetics against Anophelesculicifacies

Mosquitoes are important vectors for the transmission of several infectious diseases that lead to huge morbidity and mortality. The exhaustive use of synthetic insecticides has led to widespread resistance and environmental pollution. Using essential oils and nano-emulsions as novel insecticides is a promising alternative approach for controlling vector borne diseases. In the current study, Lantana camara EO and NE were evaluated for their larvicidal and pupicidal activities against Anopheles culicifacies. The inhibitory effect of EO and NE on AChE, NSE (α/β), and GST was also evaluated and compared. GC-MS analysis of oil displayed 61 major peaks. The stable nano-emulsion with an observed hydrodynamic diameter of 147.62 nm was formed using the o/w method. The nano-emulsion exhibited good larvicidal (LC50 50.35 ppm and LC90 222.84 ppm) and pupicidal (LC50 54.82 ppm and LC90 174.58 ppm) activities. Biochemical evaluations revealed that LCEO and LCNE inhibited AChE, NSE (α/β), and GST, displaying LCNE to be a potent binder to AChE and NSE enzyme, whereas LCEO showed higher binding potency towards GST. The nano-emulsion provides us with novel opportunities to target different mosquito enzymes with improved insecticidal efficacy. Due to its natural origin, it can be further developed as a safer and more potent larvicide/insecticide capable of combating emerging insecticide resistance.

Improving the insecticidal efficacy of Thuja orientalis essential oil by gamma radiation against Trogodermagranarium

The essential oils isolated by hydrodistillation from Thuja orientalis unripe fruits exposed to gamma radiation at dose levels of 0, 1, 3, and 5 kGy were analyzed by GC–mass spectrometry (MS) and assessed for their insecticidal activities on Trogoderma granarium Everts. The results showed slight changes were observed in the chemical composition of essential oil. The results showed that irradiated oil treatments induced higher toxicity to larvae of T. granarium than unirradiated oil with LD50 values (41.5, 54.2, and 87.1 μl/larva), and LD90 values (122.8, 207.5, and 314.7 μl/larva) for irradiated oil with 5.0, 3.0, and 1.0 kGy, respectively compared with unirradiated oil (LD50 = 153.8 μl/larva) and (LD90 = 622.8 μl/larva) by contact method. The same trend was obtained in the fumigant assay, the irradiated oil treatments with 3.0 and 5.0 kGy increased the toxicity to larvae of T. granarium than unirradiated oil with LC50 values were 280.7 and 183.6 μl/L, and LC90 values were 1171.6 and 687.4 μl/L, respectively compared with unirradiated oil (LC50 = 449.4 μl/L) and (LC90 = 1656.1 μl/L). The results showed also, that at 0.063 and 0.126 μl/cm2, the irradiated T. orientalis with 5.0 kGy, showed strong repellent activity against T. granarium larvae with the percentage repellency 100% (Class V) compared with the unirradiated oil (23.3 and 53.3%) after 2 h treatment. While at 0.252 μl/cm2, all three irradiated T. orientalis essential oil doses caused complete repellence for T. granarium larvae compared with the unirradiated oil (90%) after 2 h treatment. The present findings indicated that gamma radiation improves the insecticidal efficacy of T. orientalis essential oil and could be successfully used for the management of this insect pest.

Field efficacy of newer insecticides against leaf folder (Cnaphalocrocis medinalis Gn.) in rice

Field efficacy of newer insecticides against leaf folder (Cnaphalocrocis medinalis Gn.) in rice

Efficacy of chemical insecticides on percent mortality of mulberry thrips under laboratory condition

Efficacy of chemical insecticides on percent mortality of mulberry thrips under laboratory condition

Efficacy of Certain Insecticides against Shoot and Fruit Borer, Leucinodes orbonalis (Gueenee) on Brinjal Crop Solanum melongena (L)

A field experiment was conducted at the Central Research Farm (CRF), Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, Uttar Pradesh during Kharif season 2023. The experiment was laid in Randomized Block Design with eight treatments replicated thrice along with untreated control plot. Eight treatments viz. Novaluron @ 10% EC 0.5ml/lit, Spinetoram 11.7% SC @0.4g/lit, Emamectin benzoate 5% SG @0.4g/lit, Chlorantraniliprole 18.5SC@0.5ml/lit, Flubendiamide 39.35% SC @0.5 ml/lit, Neem oil 2% @20ml/lit, Beauveria bassiana1x108 CFU @ 2.5g/lit and untreated control were evaluated against shoot and fruit borer. During the investigation, it was revealed that the lowest percent shoot and fruit borer (Leucinodes orbonalis) infestation after 1st and 2nd spray was observed in the treatment Chlorantraniliprole 18.5 % SC i.e. 2.32% and 2.16%, followedby Emamectin benzoate 5% SG (3.21 and 2.97), Spinetoram 11.7% SC (3.81 and (3.30), Novaluron 10% EC (4.62 and 4.05), Flubendiamide 39.35% SC 5.39 and 4.903, Neem oil 2% 5.98 and 5.38 and Beauveria bassiana 1x108 CFU 6.35 and 5.48. The treatment Beauveria bassiana 1x108 CFU 6.35 and 5.48 was found to be least effective among all the treatments against Leucinodes orbonalis. The plot treated with Chlorantraniliprole 18.5% SC (241.75 q/ha, 1:13.14) was found most effective with highest yield and cost benefit ratio among all the treatment followed by Emamectin benzoate 5% SG (190.61 q/ha, 1:10.34), Spinetoram 11.7% SC (150.58 q/ha,1:7.92), Novaluron 10% EC (124.49 q/ha, 1:6.38), Flubendiamide 39.35% SC (104.34 q/ha, 1:4.34), Neem oil 2% @ (85.81 q/ha, 1:3.01) and Beauveria bassiana 1x108 CFU @ (65.83 q/ha1:2.80) as compared to untreated control plot (59.06 q/ha, 1:2.68).

Sgabd-2 plays specific role in immune response against biopesticide Metarhizium anisopliae in Aphis citricola

Metarhizium anisopliae is an effective biopesticide for controlling Aphis citricola, which has developed resistance to many chemical pesticides. However, the powerful immune system of A. citricola has limited the insecticidal efficacy of M. anisopliae. The co-evolution between insects and entomogenous fungi has led to emergence of new antifungal immune genes, which remain incompletely understood. In this study, an important immune gene Sgabd-2 was identified from A. citricola through transcriptome analysis. Sgabd-2 gene showed high expression in the 4th instar nymph and adult stages, and was mainly distributed in the abdominal region of A. citricola. The recombinant protein (rSgabd-2) exhibited no antifungal activity but demonstrated clear agglutination activity towards the conidia of M. anisopliae. RNA interference of Sgabd-2 by dsRNA feeding resulted in decreased phenoloxidase (PO) activity and weakened defense for A. citricola against M. anisopliae. Simultaneous silence of GNBP-1 and Sgabd-2 effectively reduced the immunity of A. citricola against M. anisopliae more than the individual RNAi of GNBP-1 or Sgabd-2. Furthermore, a genetically engineered M. anisopliae expressing double-stranded RNA (dsSgabd-2) targeting Sgabd-2 in A. citricola successfully suppressed the expression of Sgabd-2 and demonstrated increased virulence against A. citricola. Our findings elucidated Sgabd-2 as a critical new antifungal immune gene and proposed a genetic engineering strategy to enhance the insecticidal virulence of entomogenous fungi through RNAi-mediated inhibition of pest immune genes.

Efficacy and Economics of New Insecticides and Botanicals for Jassid Control in Mung Bean (Vigna radiata, L. Wilczek)

Efficacy and Economics of New Insecticides and Botanicals for Jassid Control in Mung Bean (Vigna radiata, L. Wilczek)

Ecofriendly synthesis of copper oxide-chitosan nanocomposites and their efficacy as nano-pesticide and nano-fertilizer

Chemical pesticides and fertilizers are a long time threat to human health and environment. One of the prime risks in pest management is the resistance to insecticide applied. There is demand for formulations which are eco-friendly, effective in small amounts, biodegradable and economically viable. The demand for organic formulations and nanomaterials to control the pests of economically important plants is rising every day. Mealy bugs and fruit flies are the major pests and their control has been a serious issue in pest management. The current research work was conducted to synthesize copper oxide nanoparticles (CuO NPs) from Eucalyptus leaves and nanocomposites comprising chitosan through a green way to evaluate the insecticidal efficacy of prepared nanomaterials. The nanomaterials were characterized by Fourier-transform infrared spectroscopy (FT-IR), UV–Visible spectroscopy, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). CuO NPs showed crystalline monoclinic structure in XRD pattern. Different concentrations of nano-pesticides were tested against mealy bugs and fruit flies to find out % mortality and LC50 values. The LC50 values in mealy bugs for extract, CuO NPs, CuO-Chitosan nanocomposites (NCs) and CuO-Chitosan NCs with Cu layer were found to be 10.45 ppm, 6.96 ppm, 4.58 ppm and 3.29 ppm, respectively. Results showed that mortality enhanced with rising pesticides concentration, so plant extract, CuO NPs, CuO-Chitosan NCs and CuO-Chitosan NCs with Cu layer showed 50 %, 70 %, 80 % and 90 % mortality at the highest concentration (10 ppm). The synthesized nanomaterials significantly improved seeds germination, yield and growth parameters in maize whenever used as nano-fertilizers. The results showed that prepared nanomaterials have good insecticidal effects as well as the best fertilizer properties. So, the products having dual application as nano-pesticides and nano-fertilizers have promising future in agriculture.

Assessing the efficacy of novel systemic insecticides on rice stem borers and their impact on beneficial insect fauna survival

Rice (Oryza sativa L.) is a staple food crop worldwide, but its production is threatened by pests like rice stem borers. Effective pest management strategies are crucial for ensuring high yields and food security. In this study, the effectiveness of various insecticides was evaluated against rice stem borers while considering their impact on the survival of beneficial insect fauna. Five treatments were tested: chlorantraniliprole, chlorantraniliprole + thiamethoxam, fipronil, flubendiamide, and a control group. The efficacy of each treatment was assessed by measuring pre- and post-treatment infestation levels of deadhearts and whiteheads, along with the survival percentage of beneficial insect fauna after one week. Chlorantraniliprole exhibited the highest effectiveness, with post-treatment percent infestation of deadhearts reduced to 2.10% after 72 hours and 1.24% after one week, and an effectiveness rate of 82.53% after 72 hours and 91.17% after one week. Chlorantraniliprole + thiamethoxam showed similar efficacy, with post-treatment percent infestation of deadhearts at 1.00% after 72 hours and 0.67% after one week, and an effectiveness rate of 91.71% after 72 hours and 95.18% after one week. Fipronil and flubendiamide also demonstrated significant effectiveness, albeit slightly lower than chlorantraniliprole-based treatments. The control group exhibited high post-treatment infestation levels and no effectiveness against deadhearts or whiteheads. However, the survival percentage of beneficial insect fauna was remarkably high in the control group. These findings highlight the potential of chlorantraniliprole and its combination with thiamethoxam as effective pest management options for rice cultivation, while emphasizing the importance of integrated approaches to minimize environmental impact. Further research is warranted to validate these results under diverse field conditions and optimize insecticide application protocols for sustainable rice production.

Insecticidal Efficacy of Diatomaceous Earth and Botanical Powders against Pulse Beetle, Callosobruchus analis F. in Stored Mung Bean (Vigna radiata L.)

The pulse beetle is the most damaging insect pest of legumes causing huge economic losses. The experiment was conducted to find out the insecticidal effects of diatomaceous earth (DE) combined with three botanical powders in three different combinations of 25% plant powder with 75% DE, 50% plant powder with 50% DE and 75% plant powder with 25% DE. The results indicated that the least number of adult beetles settled on grains treated with T9 (75% GP + 25% DE and T3 (75% NP + 25% DE) whereas maximum number of adult beetles settled in T4 (25% TP + 75% DE). After 168 hours, all the treatments showed significant mortality (100%) of adult beetles compared to control (43%). All the treatments reduced the number of eggs (3.60 to 6.80 eggs per 20 grains) in comparison to control (17.00). The maximum (28.80) days to adult emergence were documented in T9 whereas; minimum (21.40) days were recorded in untreated grains. Among all the treatments, T9: showed minimum emergence (36.40) of adult beetles whereas; the maximum (125.20) adults emerged in control. The lowest grain damage (5.50%) was observed in T9 as related to the maximum grain damage (28.96%) in the untreated control. The minimum weight loss (3.49%) was recorded in T9. The maximum weight loss (21.08%) was recorded in untreated grains. The use of diatomaceous earth in combination with garlic powder is recommended for the management of pulse beetle under storage conditions.

Recent Research Progress in Oxime Insecticides and Perspectives for the Future.

In recent decades, the unique structural attributes and purported insecticidal properties of oximes have garnered increasing attention. A variety of insecticides, encompassing fluxametamide, fluhexafon, and lepimectin, have been synthesized, all of which incorporate oximes. This review endeavors to encapsulate the insecticidal efficacy, structure-activity correlations, and operative mechanisms of oxime-containing compounds. Furthermore, it delves into the conceptual frameworks underpinning the design of innovative oxime-based insecticides, thereby shedding light on prospective advancements in this field.

Green purification of Acmella oleracea extract by wiped-film short path molecular distillation boosts the insecticidal activity on mosquito larvae

The development of insecticide resistance by mosquito vectors highlighted an urgent need for effective and sustainable botanical insecticides. Acmella oleracea R.K. Jansen (Asteraceae)-derived extracts and the major constituents N-alkylamides have already demonstrated their potential as insecticidal and acaricidal agents. Nowadays, the development of scalable green extraction and purification processes in the manufacture of biopesticides is a topic of great interest. In this context, supercritical fluid extraction and wiped-film short path molecular (WSM) distillation techniques were combined for the first time to obtain an eco-friendly N-alkylamides-enriched fraction (AEF) from A. oleracea. This was characterized by a notably higher content of spilanthol and N-alkylamides than the supercritical fluid extract (SFE), as determined by HPLC-DAD-MS analysis. The AEF also contained free fatty acids (e.g., palmitic, linoleic, and linolenic acids) as revealed by GC-FID analysis. The mosquito larvicidal activity of SFE, AEF, and pure spilanthol was assessed against 3rd instar larvae of Aedes albopictus Skuse, Anopheles stephensi Liston, and An. gambiae Giles. Results showed that AEF exhibited an insecticidal efficacy comparable with that of spilanthol, and higher than that of SFE. These products were tested against human keratinocytes (HaCaT) confirming their dermal safety. The present study paves the way for the utilization of WSM distillation in the agrochemical industry for the manufacture of botanical insecticides. Indeed, this technique allows to avoid the use of organic solvents related to conventional extraction and spilanthol isolation procedures and gives a product devoid of undesired pigments appealing to other industrial application as well.

In-Depth Structural Simplification of Celangulin V: Design, Synthesis, and Biological Activity.

Celangulin V is a novel botanical insecticide with significant bioactivity and a unique molecular target, but its complex polyol ester structure hinders its broader application in agriculture. To discover new analogues of celangulin V with a simpler structure and enhanced biological activities, we initiated a research project aimed at simplifying its structure and assessing insecticidal efficacy. In this study, a series of novel 1-tetralone derivatives were designed via a structure-based rational design approach and synthesized by a facile method. The biological activities of the target compounds were determined against Mythimna separata (M. separata), Plutella xylostella, and Rhopalosiphum padi. The results revealed that most of the synthesized compounds exhibited superior activities compared to celangulin V. Remarkably, the insecticidal activity of compound 6.16 demonstrated 102-fold greater stomach toxicity than celangulin V against M. separata. In addition, certain compounds showed significant contact toxicity against M. separata, a finding not reported previously in the structural optimization studies of celangulin V. Molecular docking analysis illustrated that the binding pocket of compound 6.16 with the H subunit of V-ATPase was the same as celangulin V. This study presents novel insights into the structural optimization of botanical pesticides.

Field efficacy of different insecticides and neem products against fall armyworm [(Spodoptera frugiperda) (J. E. Smith)] in maize (Zea mays L.)

Field efficacy of different insecticides and neem products against fall armyworm [(Spodoptera frugiperda) (J. E. Smith)] in maize (Zea mays L.)

Fabrication of dual responsive microcapsules based on starch with enhanced foliar adhesion and photostability for improving control efficacy and reducing environmental risks

Stimuli-responsive controlled release formulations offer a promising avenue for enhancing effective utilization and mitigating environmental risks of pesticides. Herein, pH and enzyme-responsive pesticide microcapsules (AVE@CPS-Fe-TA) were constructed by encapsulating carboxylated porous starch (CPS) loaded with avermectin (AVE) within tannic acid-iron complexes (Fe-TA) to improve the insecticidal efficacy and reduce toxicity to non-targets of AVE. The results showed that the loading content of AVE in the modified starch-based microcapsules could be precisely adjusted by the enzymatic hydrolysis time of starch. The prepared AVE@CPS-Fe-TA had pH and α-amylase dual responsive release properties and exhibited superior photostability, and its photolysis half-life was extended by 15.57-fold compared to AVE technical. Additionally, the leaf retention rate of AVE@CPS-Fe-TA after being rinsed by simulated rainwater was 6.08 times higher than that of commercial formulation AVE EC. In greenhouse insecticidal activity experiment, AVE@CPS-Fe-TA demonstrated a high control efficacy against Ostrinia furnacalis and had a prolonged effective duration. Moreover, AVE@CPS-Fe-TA significantly reduced the acute toxicity of AVE to zebrafish and promoted the growth of maize seedlings. Therefore, this work would provide eco-friendly stimuli-responsive microcapsules of pesticides for improving the efficiency of utilization and reducing environmental risks.

Using a rainfall simulator thrust type to evaluate the efficacy of insecticides in a apple orchard

A rainfall simulator thrust type was evaluated as a novel tool for studying the efficacy of insecticides against pests in apple orchards, compared to traditional laboratory methods. The simulator was installed and calibrated to simulate rainfalls of 50 mm h-1 on a 7-year-old apple orchard. The results of Grapholita molesta (Lepidoptera: Tortricidae) control in the field differed from those obtained in laboratory. The control efficacy in the orchard was lower than that obtained in laboratory tests. Control percentages varied throughout the simulated rains, with increases at the beginning of rainfall followed by decreases. The use of the push-type rainfall simulator provides advantages to research experiments, as it allows for evaluations under field conditions at different developmental stages of plants in orchards under different management practices, with results closer to field reality than those currently generated by laboratory tests.

Insufficient duration of insecticidal efficacy of Yahe® insecticide-treated nets in Papua New Guinea

BackgroundInsecticide-treated nets (ITNs) are the backbone of anti-malarial vector control in Papua New Guinea (PNG). Over recent years the quality and performance of ITNs delivered to PNG decreased, which has likely contributed to the stagnation in the malaria control effort in the country. The present study reports results from the first 24 months of a durability study with the ITN product Yahe LN® in PNG.MethodsThe durability study was conducted in four villages on the northern coast of PNG, in an area with high malaria parasite transmission, following WHO-recommended methodology adapted to the local scenario. A cohort of n = 500 individually identifiable Yahe® ITNs was distributed by the PNG National Malaria Control Programme from October to December 2021. Insecticidal efficacy of the ITNs was tested using cone bioassays with fully pyrethroid susceptible Anopheles farauti colony mosquitoes at baseline and at 6 months intervals, alongside evaluation of physical integrity and the proportion of ITNs lost to follow-up. A questionnaire was used to collect information on ITN end user behaviour, such as the frequency of use and washing. The observations from the durability study were augmented with simulated laboratory wash assays.ResultsGradual uptake and replacement of previous campaign nets by the communities was observed, such that at 6 months 45% of all newly distributed nets were in use in their designated households. Insecticidal efficacy of the Yahe® nets, expressed as the percent 24 h mortality in cone bioassays decreased from 91 to 45% within the first 6 months of distribution, even though > 90% of study nets had never been washed. Insecticidal efficacy decreased further to < 20% after 24 months. ITNs accumulated physical damage (holes) at a rate similar to previous studies, and 35% were classified as ‘too torn’ by proportional hole index after 24 months. ITNs were lost to follow-up such that 61% of cohort nets were still present after 24 months. Laboratory wash assays indicated a rapid reduction in insecticidal performance with each consecutive wash such that average 24 h mortality was below 20% after 10 washes.ConclusionYahe® ITNs are not performing as per label claim in an area with fully pyrethroid susceptible vectors, and should be investigated more comprehensively and in other settings for compliance with currently recommended durability and efficacy thresholds. The mass distribution of low quality ITN products with variable performance is one of the major ongoing challenges for global malaria control in the last decade.