Insecticide Applications Research Articles

Integrated control strategies for dengue, Zika, and Chikungunya virus infections.

Arboviruses are a major threat to public health in tropical regions, encompassing over 534 distinct species, with 134 capable of causing diseases in humans. These viruses are transmitted through arthropod vectors that cause symptoms such as fever, headache, joint pains, and rash, in addition to more serious cases that can lead to death. Among the arboviruses, dengue virus stands out as the most prevalent, annually affecting approximately 16.2 million individuals solely in the Americas. Furthermore, the re-emergence of the Zika virus and the recurrent outbreaks of chikungunya in Africa, Asia, Europe, and the Americas, with one million cases reported annually, underscore the urgency of addressing this public health challenge. In this manuscript we discuss the epidemiology, viral structure, pathogenicity and integrated control strategies to combat arboviruses, and the most used tools, such as vaccines, monoclonal antibodies, treatment, etc., in addition to presenting future perspectives for the control of arboviruses. Currently, specific medications for treating arbovirus infections are lacking, and symptom management remains the primary approach. However, promising advancements have been made in certain treatments, such as Chloroquine, Niclosamide, and Isatin derivatives, which have demonstrated notable antiviral properties against these arboviruses in vitro and in vivo experiments. Additionally, various strategies within vector control approaches have shown significant promise in reducing arbovirus transmission rates. These encompass public education initiatives, targeted insecticide applications, and innovative approaches like manipulating mosquito bacterial symbionts, such as Wolbachia. In conclusion, combatting the global threat of arbovirus diseases needs a comprehensive approach integrating antiviral research, vaccination, and vector control. The continued efforts of research communities, alongside collaborative partnerships with public health authorities, are imperative to effectively address and mitigate the impact of these arboviral infections on public health worldwide.

Influence of Grapevine Cultivar on Population Levels of Lobesia botrana (Lepidoptera: Tortricidae) and Effectiveness of Insecticides in Controlling This Pest

The European grapevine moth, Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae), is the most critical pest of vineyards. In the present study, pheromone-baited traps were applied in 2021 and 2022 to monitor the moth population dynamics and to determine the number of L. botrana generations. The number of eggs and larvae was also counted in four vineyards with Askari, Yaghooti, Keshmeshi, and Fakhri cultivars. Moreover, the morphological properties of clusters were evaluated in different grape cultivars to find out the susceptible cultivar to L. botrana. In 2022, different insecticides were used in the Askari cultivar vineyard, and larval damage level was assessed. Three generations were recorded in all vineyards each year. The population of males was not affected by the cultivar. In contrast, the population density of eggs and larvae was significantly higher in Yaghooti than in other tested cultivars. It could be attributed to the cluster compactness and thin skin of berries in Yaghooti, which makes it more susceptible to L. botrana infestations. In contrast, the lowest eggs and larval population density was reported in the Fakhri cultivar indicating the tolerance of this cultivar compared to the other tested cultivars. The field trial showed that the application of insecticides in the second and third generations reduced the damage level of L. botrana. The rotation of insecticides with different modes of action in consecutive generations of L. botrana can be used to reduce damage levels.

The Insect Pest Management Strategies and Their Influence on The Emergence Rate of Elaeidobius kamerunicus Faust (Coleoptera: Curculionidae) From The Post-Anthesising Male Inflorescence of Oil Palm, Elaeis guineensis

Elaeidobius kamerunicus is the main pollinating insect of oil palm, Elaeis guineensis in Malaysia. Elaiedobius kamerunicus feeds and breeds on the oil palms' male inflorescences. The weevil presence is vital for the successful pollination of oil palm, thus ensuring satisfactory fruit bunch production. MPOB recently reported that the declining quality of oil palm fruit bunch, mainly due to insufficient pollination, had affected the national average oil extraction rate. In part, this scenario was caused by the declining pollinator population. As such, the factors affecting the pollinators' population need to be investigated. One of the critical criteria in estimating the population of E. kamerunicus in the field is to measure the emergence rate of the new adult E. kamerunicus from the post-anthesis male inflorescence (PAMI). The study to investigate the rate of E. kamerunicus adult emergence and their sex ratio was conducted for four months at nine oil palm estates in Malaysia by using PAMI samples that were brought to the laboratory and observed for two weeks. The results have shown that the number of adult weevils that emerged from PAMI was about 36-47 individuals, and the female-to-male ratio for the emerged progenies was 2.33-4.46: 1. Indiscriminate application of broad-spectrum pyrethroid insecticide, cypermethrin has negatively influenced the weevil emergence rate in the field. Whereas, minimal impact on the emergence rate was observed in areas applied with biopesticide. This study showed that the application of cypermethrin could threaten the future population of the pollinating weevil in the field. As such, the excessive application of such insecticides in the field is discouraged and should be replaced by biopesticides to complement other Integrated Pest Management (IPM) strategies. In addition, further investigation is needed to understand how the gender ratio of the progeny could affect the future population of E. kamerunicus.

Environmental problems of insecticides application in agriculture to combat blood-sucking dipterous insects

This article discusses scientific studies that indicate the negative factors that arise when using insecticides to combat blood-sucking diptera insects. Diptera insects are carriers of viral diseases of humans and animals, such as anthrax, tularemia, diphtheria, anaplasmosis and others. They also contribute to the transmission of invasive diseases, which further increases their harmfulness. To reduce the economic damage caused by insects, various preventive and extermination measures are used, where the main method is the use of insecticides. However, more and more studies point to the negative impact of chemical insecticides on the environment and non-target organisms, including humans. This may indicate that the scale of the use of insecticidal drugs is far ahead of the study of the consequences associated with their use. Therefore, the current situation requires a reassessment of this approach to pest control. To collect information, a search was made for scientific papers in Russian and foreign sources on the negative consequences of the use of insecticides and alternative approaches to pest control. Research in this area is necessary to develop effective and environmentally friendly pest control strategies and minimize losses in animal husbandry. To overcome the environmental problems associated with the use of insecticides in animal husbandry, an integrated approach is considered, which includes a variety of tactics based on alternative methods of disinsection and combining mechanical, cultural, biological and chemical methods of pest control while minimizing the use of insecticides.

Assessment of factor productivity and individual input effect on yield and economics of soybean [Glycine max (L.) Merrill

In India, the area under soybean is steadily increasing, while production and productivity is comparably low to the world average. To bridge this gap, production factors deciding per-unit production plays a vital role. In the present study, soybean grown with full package (2371 kg/ha) gave significantly higher yield over omission of weed management (1873 kg/ha) and insecticide application (1993 kg/ha). Increase in seed yield with full package over omission of weed management was (21.00%) and omission of insecticide application was (15.94%). The yield gap was higher with weed management (498 kg/ha) and insecticide application (378 kg/ha). Economic gain due to full package was maximum (Net Returns: Rs. 88226/ ha) compared to omission of individual factors.

Efficacy of Four Insecticides Applied to Fortified Rice with Basil against Major Stored-Product Insect Species

Rice is one of the most important foods since it is grown in many countries and consumed by the majority of the population. Ensuring food security through the protection of stored-product commodities has become one of the most important priorities worldwide. In this study, the effects of three insecticidal formulations and an available diatomaceous earth formulation on basil-fortified rice against the major stored-product insects were evaluated. The label dose of each insecticidal formulation was used. Insect mortality was determined after 1, 3, 7, 14 and 21 days for each species. The entire experiment was repeated three times by preparing different lots of treated and untreated rice for each treatment. The results of the diatomaceous earth treatments showed that the most susceptible individuals were Sitophilus oryzae adults and Oryzaephilus surinamensis larvae, while the least susceptible individuals were Rhyzopertha dominica and Tribolium castaneum adults. The tested insecticides were effective against S. oryzae, as mortality was 100%. Between the two pyrethroids, deltamethrin was more effective than cypermethrin in the tested insecticides. Our findings indicate that there are available insecticides on the market which can be obtained successfully for the durable protection of agricultural commodities after the harvest stage.

Protection of soybean plants from phytophages under conditions of the Primorsky Territory

The effectiveness of pre-sowing treatment of soybean seeds and application of biorational insecticides in reducing the number of major pests of soybean in the conditions of the Primorsky Territory have been studied. The results of using insecticides and biopreparations to regulate the number of dominant pests of soybean have been presented. The studies were conducted in 2020 and 2021. The efficiency of insecticidal protectants Imidor Pro, SC (2 l/t) and Tabu, WSC (1.0 l/t), bioinsecticides Fitoverm, EC (0, 16 l/ha), Proclaim, WSG (0.3 kg/ha), Batsikol, L (15 l/ha), Biosleep BW, L (2 l/ha), Biosleep BT, P (2 kg/ha) against two-striped leaf beetle (Medythia nigrobilineatus Motsch.) and soybean pod borer (Leguminivora glycinivorella Mats.) were studied. Pre-sowing seed treatment with insecticides Imidor Pro and Tabu reduced damage of soybean plants in the sprouting phase by Medythia nigrobilineatus beetles compared to the control by 94.0–98.2%. Seed dressing with imidacloprid-based preparations provided effective protection of crops against the pest in the sprouting – branching phase. Biorational insecticides based on avermectin C and Bacillus thuringiensis showed high biological efficacy (71.1–98.8%) on the 5–10th day after treatment against the two-striped leaf beetle. Soybean seed damage when bioinsecticides were used against Leguminivora glycinivorella was 1.9–3.0% compared to 5.6% in the control. The conducted studies testify to the prospect of using the preparations of biological origin to control the number of dominant pests in soybean crops.

Frequent insecticide applications in cotton fields offset the positive impact of surrounding semi-natural habitats on in-field ladybeetle abundance

Frequent insecticide applications in cotton fields offset the positive impact of surrounding semi-natural habitats on in-field ladybeetle abundance

Field efficacy of botanicals and beneficial microbes to control banana mealybug (Pseudococcus elisae Borchsenius) (Hemiptera: Pseudococcidae)

The banana mealybug (Pseudococcus elisae Borchsenius) causes significant economic losses to banana production. Prior to the 2019 ban of the organophosphate chlorpyrifos use in commercial banana production systems due to high chlorpyrifos residue levels on banana fruits, chlorpyrifos-treated exclusion bags were commonly used to mitigate mealybug infestation on banana bunches and fingers. Short- and long-term effects of 2 beneficial microbes (Beauveria bassiana and Kosakonia radicincitans), 2 neem-based botanicals (Orgamix and Rata®), 3 chemical insecticides Pyriforce® (Chlorpyriphos-ethyl), Calixine Super® (Acetamipride and Bifenthrin), and Parastar EC40® (Imidachlorpride and Lambda-cyhalothrin), and tap water (Control) were evaluated on mealybug in a newly established and 5-year-old banana farms. Mealybug sampling was conducted for three months after each insecticide application and their population dynamics was calculated using Mann-Kendall trend statistics (S). For the 5-year-old banana farm, except the control, all treatments caused significant (P < 0.05) short-term reduction in mealybug population from pre-treatment application to 5 days in March, July and November samplings. Mealybug population reduction in March was greater than 90% for Calixine Super®, Orgamix and Beauveria, and between 80% and 90% for Kosakonia, Rata and Parastar EC40® (P < 0.05). A similar trend was recorded in July and November, with a higher reduction for Beauveria (52.08%) in July. An increasing linear mealybug trend was observed between March and June (S was positive, P > 0.05) across all treatments, while Orgamix and Rata® caused downward trend between July and October. A downward mealybug trend occurred for Parastar EC40® (S = −1), Rata® (S = −3), Beauveria (S = −6) and Kosakonia (S = −3) between November and January. Biorationals effectively reduced mealybug populations better than chlorpyrifos, while beneficial microbes and neem-based botanicals demonstrated long-term potency on mealybug.

Transgenerational hormesis and sublethal effects of five key insecticides for controlling Spodoptera frugiperda on its endoparasitoid Cotesia marginiventris.

The endoparasitoid Cotesia marginiventris (Cresson) is a promising biological control agent of the fall armyworm (FAW) Spodoptera frugiperda (Smith). Because the application of insecticides is one of the prime choices in pest management, we evaluated the sublethal and transgenerational effects of the five key insecticides-chlorantraniliprole, emamectin benzoate, spinetoram, Bacillus thuringiensis (Bt), and Mamestra brassicae nucleopolyhedrovirus (MbNPV)-on the parasitoid. Exposure to five insecticides at a concentration causing 10% mortality (LC10 ) caused hormetic effects in the parent generation (F0 ) by increasing the parasitism and reducing the immature duration. Interestingly, the hormetic response was also observed in the offspring generation indirectly exposed to the insecticides. Furthermore, insecticides increased the parasitism rate by 6.32-14.73% in the F1 generation, which was similar to that of the F0 generation (3.96-11.81%) compared with the control. No significant adverse effect was observed on the number of emerged parasitoids of the F1 and F2 generations. However, insecticides had a detrimental impact on body size and fecundity in the F1 and F2 generations, which showed a small body size with shorter hind tibiae and a significant reduction in the female ratio compared with the control; the exception was that chlorantraniliprole significantly improved the female ratio in the F2 generation. Five insecticides at LC10 induced transgenerational hormetic and sublethal effects on C. marginiventris. Our results provide a scientific basis for a better understanding of the long-term impacts of insecticides at sublethal doses on parasitoids, facilitating the development of improved integrated pest management programs for FAW control. © 2023 Society of Chemical Industry.

Electrical signalling and plant response to herbivory: A short review

ABSTRACTFor a long time, electrical signaling was neglected at the expense of signaling studies in plants being concentrated with chemical and hydraulic signals. Studies conducted in recent years have revealed that plants are capable of emitting, processing, and transmitting bioelectrical signals to regulate a wide variety of physiological functions. Many important biological and physiological phenomena are accompanied by these cellular electrical manifestations, which supports the hypothesis about the importance of bioelectricity as a fundamental ‘model’ for response the stresses environmental and for activities regeneration of these organisms. Electrical signals have also been characterized and discriminated against in genetically modified plants under stress mediated by sucking insects and/or by the application of systemic insecticides. Such results can guide future studies that aim to elucidate the factors involved in the processes of resistance to stress and plant defense, thus aiding in the development of successful strategies in integrated pest management. Therefore, this mini review includes the results of studies aimed at electrical signaling in response to biotic stress. We also demonstrated how the generation and propagation of electrical signals takes place and included a description of how these electrical potentials are measured.

Biological control of sesame moth and tobacco whitefly in Antalya sesame fields

Sesame moth and tobacco whitefly cause significant damage to sesame plants, especially in the second-period sesame cultivation areas, if early intervention is not implemented. This greatly reduces efficiency. Chemical control is generally preferred for these pests in Türkiye. Today, the use of chemical control creates many harmful results. Therefore, in our study, the aim is to use biological control agents and preparations as an alternative to chemical control. In this study, applications of Nostalgist Bl biological insecticide containing 1.5% Beauveria bassiana strain Bb-1 1x108 CFU mil-1 spores, Nimbecidine biological insecticide containing 0.3 g L-1 Azadirachtin active ingredient, and Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) an egg parasitoid and activities were determined. The application area (2 da) was divided into 3 blocks; each block was named with the letters A, B, and C. Each block was divided into four parcels. The above applicatios and biological insecticides were applied separately in each parcel, including the control parcels in each block. In the counts made according to the application results, there was a significant decrease in whitefly eggs and nymphs on the leaf surface. A very significant decrease was observed in the populations per plant in the sesame moth larvae counts. The highest efficiency was obtained with Nimbecidine and Nostalgist applications. The yield was moderate in the plots with parasitoid application.

Targeted indoor residual insecticide applications shift Aedes aegypti age structure and arbovirus transmission potential

While residual insecticide applications have the potential to decrease pathogen transmission by reducing the density of vectors and shifting the age structure of the adult mosquito population towards younger stages of development, this double entomological impact has not been documented for Aedes aegypti. Aedes collected from households enrolled in a cluster-randomized trial evaluating the epidemiological impact of targeted indoor residual spraying (TIRS) in Merida, Mexico, were dissected and their age structure characterized by the Polovodova combined with Christopher’s ovariole growth methods. In total, 813 females were dissected to characterize age structure at 1, 3, 6, and 9 months post-TIRS. Significant differences in the proportion of nulliparous Ae. aegypti females between the treatment groups was found at one-month post-TIRS (control: 35% vs. intervention: 59%), three months (20% vs. 49%) but not at six or nine months post-TIRS. TIRS significantly shiftted Ae. aegypti age structure towards younger stages and led to a non-linear reduction in survivorship compared to the control arm. Reduced survivorship also reduced the number of arbovirus transmitting females (those who survived the extrinsic incubation period). Our findings provide strong evidence of the full entomological impact of TIRS, with important implications for quantifying the epidemiological impact of vector control methods.

English

Dusky cotton bug (DCB), Oxycarenus hyalinipennis, a serious economic sucking insect pest of cotton, is a cosmopolitan polyphagous pest with the potency to develop resistance against insecticides. The resistance was evaluated against insecticides of different chemical nature against DCB population from three cotton fields i.e., unsprayed population (Un-sp), field exposed to sucking sprays (SSp) and field exposed to bollworms sprays (BSp) using semi-opened bolls dip method.The DCB population showed differential range of resistance level against tested insecticides. These RR ratios were among susceptibility (1 fold) and tolerance to low resistance (2–10 fold) for all tested insecticides except for deltamethrin with moderate resistance (11–30 fold) for the populations of both sprayed fields. In the order of resistance for the SSp population, deltamethrin (24.4 fold) was followed by imidacloprid (6.4 fold), profenofos (4.0 fold), cypermethrin (3.2), endosulfan (2.8 fold), chlorfenapyr (2.7 fold) and chlothianidin (2.5 fold). For BSp population, RR ratios from high to low were: deltamethrin (21.2 fold) followed by imidacloprid (4.9 fold), chlothianidin (3.7 fold), cypermethrin (2.8 fold), endosulfan (2.7 fold), triazophos (2.4 fold) and profenofos (2.2 fold). Acephate was highly effective with least LC50 followed by spinosad and dimethoate, whereas, lambdacyhalothrin was least effective. Relative toxicity (RT) order from high to low for SSp population was acephate (1.00) followed by spinosad (1.33), chlorfenapyr (2.69), acetamiprid (2.77) and dimethoate (2.85). For BSp population, RT were sequenced as acephate (1.00) followed by spinosad (1.46), chlorfenapyr (1.67) and dimethoate (3.32). In control unsprayed population, RT were in order as acephate &lt; deltamethrin &lt; spinosad &lt; chlorfenapyr (1.0, 1.20, 1.28 and 1.58, respectively). Lambdacyhalothrin was the least toxic against DCB population of all tested fields. From results, it can be suggested that regular insecticide resistance monitoring is crucial to avoid incidence(s) in O. hyalinipennis, and to adopt the rotational application of appropriate insecticides.

Effects of Insecticide Drench Application against Immatures of Systena frontalis in Container-grown Hydrangea paniculata

Systena frontalis (F.) (Coleoptera: Chrysomelidae), commonly referred to as the redheaded flea beetle, is a serious pest in container nurseries, as adult feeding defoliates nursery crops and affects plant salability. Because the foliar application of insecticides provides inconsistent efficacy, additional and alternative control tactics are sought to target immatures of this pest in growing media. Thus, the objective was to determine the effects of non-neonicotinoid insecticides applied as a drench to growing media on immatures of S. frontalis. In 2021 and 2022, nine active ingredients were evaluated in four trials in a Georgia nursery and at a Virginia research and extension center. If available, the maximum label rates for flea beetles or other coleopteran pests were applied once to Hydrangea paniculata Siebold containers (11.4 L, 3 gal) as a drench application. The emergence of S. frontalis adults from treated growing media and foliar feeding damage was lower for the tetraniliprole (TetrinoTM) and spinetoram + sulfoxaflor (XXpire®) treatments than for nontreated plants. Cyclaniliprole (SarisaTM) and chlorantraniliprole (Acelepryn®) suppressed S. frontalis adult eclosion with less feeding damage than the nontreated plants. Tetraniliprole, spinetoram + sulfoxaflor, and cyclaniliprole are not labeled for drench application. Dinotefuran (Safari®) effectively reduced adult emergence and feeding damage. Species used in this study: Redheaded flea beetle, Systena frontalis (F.); panicled hydrangea, Hydrangea paniculata Siebold. Chemicals used in this study: Cyantraniliprole (Mainspring®GNL), chlorantraniliprole (Acelepryn®), tetraniliprole (TetrinoTM), cyclaniliprole (SarisaTM), Spinetoram + Sulfoxaflor (XXpire®), tolfenpyrad (Apta®), Chromobacterium (Grandevo®CG), flupyradifurone (AltusTM), dinotefuran (Zylam® Liquid, Safari® 20G), and polyterpenes pinene (NuFilm® P).

Palmer Amaranth (Amaranthus palmeri) Control in Dicamba-Tolerant Cotton (Gossypium hirsutum) when Applied with Various Dicamba + Insecticide Tank-Mixtures

Postemergence herbicide application timings for Palmer amaranth (Amaranthus palmeri) often coincide with foliar insecticide applications in cotton (Gossypium hirsutum). Combining multiple pesticides into a single application increases efficiency while reducing overall application cost. Multiple foliar insecticides are now labeled for dicamba tank-mixes. However, there is limited literature with respect to efficacy of dicamba on Palmer amaranth control when applied with insecticides. Field experiments were conducted from 2018 to 2020 to evaluate the effect of carrier volume and insecticide on the efficacy of dicamba (XtendiMaxTM with VaporGripTM) to control Palmer amaranth in XtendFlex™ cotton production systems. Dicamba was tank-mixed with acephate and dimethoate to four-leaf cotton and with thiamethoxam and sulfoxaflor just prior to bloom. Applications were made at carrier volumes of 140 and 280 L ha-1 and with a single spray droplet size of 800 µm. Palmer amaranth control 7 d after treatment was negatively impacted when applications included dimethoate; however, no corresponding response in seedcotton yield was observed relative to dicamba applied alone. However, when pooled over carrier volume, applications containing dicamba + acephate resulted in higher seedcotton yield than applications of dicamba + dimethoate. Additionally, pre-bloom applications of dicamba + thiamethoxam or sulfoxaflor increased Palmer amaranth efficacy relative to dicamba applied alone. Although certain insecticides are known to increase herbicidal crop response, the impact of insecticides on herbicide efficacy to control specific weed species is largely unknown. Therefore, we conclude that multiple dicamba + acephate, thiamethoxam, or sulfoxaflor tank-mixtures provide similar control of Palmer amaranth compared to dicamba alone.

The Lethal and Sublethal Effects of Lambda-Cyhalothrin and Emamectin Benzoate on the Soybean Pest Riptortus pedestris (Fabricius).

Riptortus pedestris (Fabricius, 1775) (Hemiptera: Alydidae) is a major soybean pest in East Asia that can cause soybean staygreen syndrome. To date, no insecticides have been registered for the control of R. pedestris in China, and these insects are primarily controlled in the field through the application of broad-spectrum insecticides including lambda-cyhalothrin (LCT) and emamectin benzoate (EMB). Here, the lethal and sublethal effects of LCT and EMB on R. pedestris were comprehensively evaluated. LCT and EMB were both found to exhibit high levels of toxicity and concentration-dependent repellent effects for R. pedestris. The exposure of third instar nymphs from the F0 generation to LC30 concentrations of LCT and EMB resulted in a significant increase in the duration of nymph development and adult pre-oviposition period (APOP), together with reductions in fifth instar nymph and adult body weight, longevity, oviposition days, fecundity, vitellarium length, lateral oviduct diameter, and vitellogenin (Vg) gene expression as compared to control treatment. Strikingly, these suppressive effects were transmitted to the F1 generation, which similarly experienced the prolongation of preadult development and the preoviposition period (TPOP). Relative to control-treated populations, the F1 generation for these insecticide-treated groups also exhibited significant decreases in population parameter values. Overall, these data offer new insight into the impact that LCT and EMB treatment can have on R. pedestris, providing a valuable foundation for the application of these pesticides in the context of integrated pest management strategies aimed at soybean crop preservation.

Effect of α-cypermethrin and pirimiphos-methyl on wing morphology of Tribolium castaneum (Herbst) and T. confusum Jacquelin du Val: a comparative study

Tribolium castaneum (Herbst) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) are widespread and serious pests of stored products. Various insecticides are applied aiming to effectively manage both species. Here, two insecticides are tested, the pyrethroid α-cypermethrin and the organophosphate pirimiphos-methyl, hypothesizing that they can lead to morphological changes in the certain body parts of the adult offspring of treated T. castaneum and T. confusum parental female adults. For this purpose, the geometric morphometric method to the elytra and hindwings was applied. Both males and females were included in the analysis. The results showed that adult individuals of T. confusum showed higher tolerance to both insecticides compared to T. castaneum adults. This finding is reflected in analyses of both pairs of wings in T. confusum where changes in shape were negligible. The hindwings of T. castaneum experienced deformations to both insecticides. More significant changes in wing shape were observed in the α-cypermethrin treatment compared to pirimiphos-methyl. In the case of T. castaneum, even the shortest exposure to insecticides (5 min) is enough to provoke shape changes in the hindwings. Deformities in offspring, caused after treatment of their parents with insecticides, could moderate the frequency of insecticidal applications in storages.

Impacts of cultivar and management practices on the diversity and population dynamics of mites in soybean crops.

The objective of this study was to evaluate the diversity and population dynamics of mites in soybean crops with different cultivars and management practices. The study was conducted in two soybean production fields in the municipalities of Mato Queimado (L1) and Três de Maio (L2), Rio Grande do Sul state, Brazil. Two transgenic cultivars were used, and insecticide applications varied among treatments. Sampling began at the V2 stage, with 60 leaves/area/collection that were sorted, mites were collected and identified using dichotomous keys. A total of 18,100 mites belonging to 12 species were found. Among the species, Tetranychus urticae Koch, Mononychellus planki (McGregor), and Tetranychus ludeni Zacher (Tetranychidae) were the most abundant, whereas the most abundant predatory mites were the phytoseiids Neoseiulus californicus McGregor and Neoseiulus idaeus Denmark and Muma, with N. idaeus being more abundant and present in all areas. The acarofauna was influenced by environmental conditions and management practices. Neoseiulus idaeus was commonly associated with populations of M. planki, T. ludeni, and T. urticae. Neoseiulus californicus tolerated pesticide use but was affected by severe water stress, whereas N. idaeus tolerated periods of low relative humidity and high temperatures.

Isolation, characterization and docking analysis of insecticidal compound from Ocimum canum methanolic leaf extracts and its potential against three mosquito vectors

Vector management is an important challenge and burden to developing countries. Frequent and indiscriminate application of chemical insecticides for vector control has resulted in the development of resistance and undesirable effects on beneficial organisms. Hence an alternative approach is needed for the mosquito control programme. The present study investigated the insecticidal activity and spectral analysis of Ocimum canum methanol leaf extract against three mosquito species. One out of four fractions (F1-F4), the 4th fraction, revealed showed good insecticidal activity in larva and adult Cx. quinquefasciatus, Ae. aegypti and An. stephensi (0.114, 0.325 and 0.173 ppm) and (1.798, 1.061 and 0.871 ppm). The mortality was found to be dosage dependant. Spectral analysis of 1H NMR and 13C NMR indicates the presence of 6 protons at δH value of 7.45 (s) and 3 protons at δH value of 7.85 (s) ppm. FT-IR identified the possible band near the capping region at 3417.16 cm-1. LC-MS confirmed the eugenol compound with 99.79% purity at the molecular weight of 164. Further, eugenol docking analysis revealed high homology similarity with insect odorant binding protein 3OGN and AchE protein 2BG9. Overall, the result suggests that isolated eugenol compounds were found to be effective for the eco-friendly management of mosquito vectors. These findings could be useful for designing an efficient mosquitocidal compound in the future.