Chemical Insecticides Research Articles

Efficacy of New Chemistry Insecticides against Brinjal Shoot and Fruit Borer (Leucinodes orbonalis)

Solanum melongena, or brinjal, a vital vegetable crop in Pakistan, faces significant damage from the primary pest, brinjal shoot and fruit borer (BSFB), Leucinodes orbonalis , highlighting the urgent need for new chemistry insecticides. The present study investigated the impact of various insecticides on the infestation of BSFB). All insecticides demonstrated a significant reduction in infestation compared to the control, with varying levels of effectiveness. Emamectin benzoate and chlorantraniliprole emerged as the most effective, achieving a 13.33% infestation reduction at 15 days after spray (DAS). Lambda cyhalothrins exhibited similar infestation levels at 15 DAS but with a higher cumulative mean infestation of 13.33%. Imidacloprid and nitenpyram were the least effective, with infestation levels of 26.66% and 20.66% at 15 DAS, respectively. Intermediate efficacy was observed with other insecticides, with infestation levels ranging from 16.66% to 20.66% at 15 DAS. Following subsequent insecticide applications, a consistent reduction in infestation was observed for all treatments compared to the untreated control. Chlorantraniliprole demonstrated the highest efficacy, reducing infestation to 6.66% at 15 DAS, while imidacloprid exhibited the least effectiveness with infestation levels of 23.33% and 20% at 3 and 15 DAS, respectively. Emamectin benzoate remained the most efficacious insecticide in the third spray, achieving a notable reduction to 10% at 15 DAS. The study highlights the temporal decrease in infestation for most treatments over time, contrasting with the steady increase observed in the untreated control group. The findings emphasize the varying efficacy of insecticides in managing BSFB infestation and provide valuable insights for pest control strategies in brinjal cultivation.

Effect of Entomopathogenic Fungi to Eggs and Nymphs Survival of Halyomorpha halys (Hemiptera: Pentatomidae) Under Laboratory Conditions.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is becoming a major pest of Greece's agricultural production, including tree fruit. Until now, the control of this pest has been based on conventional methods, with the application of chemical insecticides being the primary option. However, the wide distribution of H. halys, in combination with the large area of tree fruit production in Greece, raise the need for alternative control methods. In this study, we investigated the possibility of implementing microbial control agents for managing H. halys. Eggs and nymphs of H. halys were treated with 15 native entomopathogenic fungal isolates and their virulence was evaluated in the laboratory. After treatment, egg hatching time was recorded for 7days and ranged from 4.5 to 7.0days. Nymphal survival was recorded daily for 7days following application and ranged from 2.1 to 6.6days for second instar nymphs and 3.7 to 6.8days for fourth instar ones. Beauveria varroae isolate displayed the highest toxicity to all H. halys stages that were tested and could be considered a promising biocontrol agent of this insect. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.οκ.

Comparison of bio-efficacy of some plant extracts and new chemistry insecticides against Bemisia tabaci (Gennadius) and Water Productivity of Cotton Varieties under High Efficiency Irrigation System

Cotton is an important cash crop in Pakistan. But insect pests attack and emerging water scarcity glitches are alarming the crop yield on sustainable basis. Hence, the present research trial was executed to probe out the toxic effects of plant extracts and some insecticides against cotton whitefly, Bemisia tabaci. Different concentrations of the plant extracts and insecticides were applied. Results showed that highest mean incidence (10.6 adults/plant) of whitefly population was observed in case of BS-15 variety, was under double Lateral+30 cm P×P distance while in case of NIAB-878, the value was 13.1 adults/plant. Results to toxicity bioassays showed that maximum population reduction (79.10%) was recorded in case of pyriproxyfen while comparative less reduction (51.17%) was observed in case of dine to furon after exposure period of 72 (h.). . The values were after 48 and 24 h. In case of plant extracts, highest mortality (51.46%) was noted in case of A. indica whereas comparatively low mortality (46.32%) was recorded in case of M. oleifera extract at 30% concentration of plant extracts after exposure period of 72 (h.). 20 and 10% concentrations of the tested plant extracts showed relatively lower mortality values. Data of morphological growth showed that plant height got increased by increasing planting distance from 30 to 40 cm in case of the both varieties. Number of leaves and boll size did not increase with increasing planting distance in case of BS-15 variety whileincreased in case of NIAB-878 variety and the values were 105.1 (number of leaves), 44.4 (number of bolls) and 10.2 cm2 (boll size). Crop water productivity of variety BS-15 was higher (0.51 kg m-3) as compared to NIAB-878 (0.49 kg m-3). It is concluded that the variety BS-15 performed better under single lateral system while variety NIAB-878 performed better under double lateral system. Plant to plant distance of 30 cm was found better than 40 cm distance. Keywords: Cotton varieties, morphogical characteristics, drip irrigation, Planting geometry.

Combination effect of azadirachtin and chlorantraniliprole with three synergists against a serious invasive agricultural pest Spodoptera frugiperda (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda, is a newly invading polyphagous pest that affects crops such as maize, sorghum, and corn in India. The pest has developed resistance to various chemical insecticides, including Bt toxins and insect growth regulators. Therefore, there is an urgent need for alternative methods to manage this pest. The present study aimed to investigate the effect of three synergists in combination with pesticides. The results showed a high resistance ratio to chlorantraniliprole (RR-52.7) and low resistance to azadirachtin (RR-3.8) in the HSR field population compared to the susceptible population (Sus). In vitro enzyme inhibition experiments with PBO and TPP synergists revealed that resistance to chlorantraniliprole was mediated by esterase, GST and MFO. However less resistance to azadirachtin was mediated by esterase enzyme. The field population exhibited a 2.0-fold higher esterase activity (20 μmol/min/mg protein) in response to chlorantraniliprole, followed by MFO activity (30–32 μmol/min/mg protein). Gene expression analysis revealed four genes (CYP321A7, CYP321B1, CYP4C71, and CYP4G74) were differentially expressed in the HSR population (4.0–6.0-fold) in chlorantraniliprole treatment and no expressions were seen in azadirachtin treatment. Overall the study concludes that, possible mechanism of chlorantraniliprole resistance in S. frugiperda mediated by P450s, esterases and GST and less resistance to azadirachtin by esterase suggesting that combination of synergists with azadirachtin could be useful for management of Spodoptera frugiperda.

Larvicidal activity of cloves as an alternative to chemical control in mosquito vectors in the Amazonia under laboratory conditions

Mosquito-borne diseases continue to be the main causes of death in many tropical countries. Among the infectious diseases transmitted by mosquitoes, malaria and dengue fever remain a major public health concern. Chemical control is the most widely used method for controlling and preventing mosquito-borne diseases. However, there are reports in the literature about resistance in populations due to the continuous use of chemical insecticides. In this sense, products of plant origin, such as plant extracts, essential oils and plant derivatives, have emerged as a promising alternative. In this study, bioassays were carried out to evaluate the activity of the aqueous and methanolic extracts of cloves (Syzigium aromaticum) in laboratory conditions against Anopheles darlingi and Aedes aegypti larvae. The bioassays carried out with An. darlingi showed CL50 values of 6.41 µg/mL for the methanolic extract and CL50 values of 5.65 µg/mL for the aqueous extract. Considering the bioassays with Ae. aegypti larvae (aqueous extract), the CL50 value was 78.81 µg/mL and the methanolic extract showed a CL50 value of 131.10 µg/mL. The larvicidal activity of the methanolic extract (CL50 131.10 µg/mL) against Ae. aegypti larvae was much lower than that obtained with An. darlingi. Comparing the two mosquito species, An. darlingi was more susceptible to the aqueous and methanolic extracts. However, when comparing the activity of the extracts against An. darlingi, it was found that the aqueous and methanolic extracts were active. With regard to Ae. aegypti larvae, they were more susceptible to the aqueous extract.

Synthesis, characterization and insecticidal activity of Mentha spicata essential oil loaded polymeric nanoparticles

Chemical insecticides are often employed to manage stored grain pests. However, their use could have severe consequences for consumers and the environment. Thus, nanotechnology could present intriguing answers to issues related to agricultural and the food sectors. In the present investigation, Mentha spicata essential oil (MsEO) loaded chitosan nanoparticles (MsEO/CSNPs) were synthesized and characterized using FTIR, SEM, TEM, DLS and XRD. It was observed that the average size of the nanoparticles ranged between 50 and 200 nm with 0.428 and 0.222 PDI for the MsEO loaded chitosan nanoparticles (MsEO/CSNPs1) and MsEO loaded chitosan nanoparticles (MsEO/CSNPs2), respectively. SEM and TEM studies revealed spherical nature of the nanoparticles. Loading Capacity (LC) was found to be 6.62–4.19% and encapsulation efficiency (EE) ranged from 79.5 to 82.5% in MsEO/CSNPs1 and MsEO/CSNPs2. Further, MsEO-loaded chitosan nanoparticles (MsEO/CSNPs1 and MsEO/CSNPs2) demonstrated excellent antioxidant activity with IC50 values of 24.2 μg/mL and 30.9 μg/mL, suggesting that MsEO/CSNPs might be employed for an effective natural antioxidant agent. The synthesized MsEO/CSNPs showed strong insecticidal efficacy when used for Callosobruchus maculates (LC50 56 μL/L) and Sitophilus granaries (LC50 47 μL/L) in toxicity tests. These nanoparticles were also tested for cytotoxicity on the Vero cell line, and the results revealed that they were nontoxic. The findings demonstrate that Mentha spicata essential oil (MsEO) loaded chitosan nanoparticles (MsEO/CSNPs) is an innovative development that might be used in a food storage pest control strategy for Callosobruchus maculatus and Sitophilus granaries.

Efficacy of Chemical and Biological formulations, and Plant extracts on the mortality of the third larval stage of tomato leaf moth Tuta absoluta (Meyrick 1917) (Lepidoptera: Gelechiidae) in vitro

Tomato in Iraq and most Middle East areas can be infected by tomato leave moth which contributes to reducing the total yield. Utilization of pesticides may lead to resistance problem in most of treated pests, which make the control of this difficult. In addition, chemical pesticides can cause climate pollution, and high cost if use continuously. Thus, this study investigates the efficacy of some of chemical and biological formulations and two plant extracts and its combinations in killing of the third larval stage of the insect. Three concentrations (field dose -50%, field dose and field dose +50%) for each of chemical insecticides (Coragen, Simpleo, and Acetamprid) and bioformulation of (Bacillus thuringiensis), and the mixture of oil extraction of garlic and Neem. Result showed that there is a significant variation between the concentration of treatments, third concentration (field recommended dose + 50%) gave the higher mortality. Treatment with Acetamprid insecticide showed a significant efficacy after 72 hours which achieved 83.33%, then Coragen insecticide by 56.66%. While, Sumipleo insecticide gave the lower mortality 36.66% of the third larval stage. The combination of evaluated factors and time exposure showed the superiority of (Bt + Coragen + Mixture of neem and Garlic oils) integrated treatment by achieving mortality of 86.66% after 72 hours of treatment, followed by mixture of garlic and neem oils 76.66% and treatment of (Bt + mixture of neem and Garlic oils) by 71.65%, while the treatment of (Bt+ Sumipleo + mixture of garlic and neem oils) gave the t mortality of 45.00% only.

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.

Comparative effectiveness of biorational pesticides for management of Phenacoccus solenopsis Tinsley and Paracoccus marginatus Williams & Granara de Willink in Gymnema sylvestre (Retz.) R.Br. ex Sm

The cotton mealybug, Phenacoccus solenopsis Tinsley and papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) are becoming major threats to the production of Gymnema sylvestre R. Br. (Asclepiadaceae) in India. Management mainly depends on chemical insecticides which cause a serious problem of pesticide residue and insecticide resistance. The use of biorational insecticides such as biopesticides, botanicals, insect growth regulators, and microbial insecticides is important components of an Integrated Pest Management (IPM) program for successful management. We evaluated the bio-efficacy of twelve biorational insecticides, including entomopathogenic fungi (EPF), using the leaf spray method in laboratory conditions at 25 ± 1 °C, 70 % ± 5 % RH. The results revealed that the highest percent mortality was recorded by acetamiprid 20 % SP (100.00 %), followed by azadirachtin (98.27 %), Lecanicillium muscarium (2 × 109 spores/mL) (85.70 %) and Ocimum sanctum leaf extract (76.87 %) at 120 h after treatment (HAT) in P. solenopsis. In P. marginatus, 100.00 %, 96.39 % and 85.67 % and 74.90 % mortalities were achieved by acetamiprid 20 % SP, azadirachtin, L. muscarium (2 × 109 spores/mL) and O. sanctum leaf extract, respectively, at 120 HAT during the first spray. Various biorational insecticides showed a more or less similar trend of percent mortality in both species during the second spray. In both species, the lowest percent mortality was recorded by Andrographis paniculata leaf extract (46.29, 44.54) and (41.03, 46.39) at 120 Hours after treatment in the first and second spray, respectively. It was concluded that all the prescribed treatments are more effective than the control. Overall, azadirachtin recorded the highest percent mortality after acetamiprid and had the shortest LT50 (12.52 h) and (13.87 h) values in P. solenopsis and P. marginatus, respectively. Our study emphasizes that biopesticides like Azadirachtin 1 % EC (10000 ppm), L. muscarium (2 × 109 spores/mL) (5 mL/L) and O. sanctum leaf extract (5 %) may be recommended as alternatives to synthetic insecticides. Botanicals and EPF would be the most effective approach for sustainable integrated management of P. solenopsis and P. marginatus in the G. sylvestre ecosystem.

Evaluation of Some Botanical Extracts and Chemical Insecticides against Cabbage Aphids, Brevicoryne brassicae L. (Hemiptera: Aphididae) on Cabbage (Brassicae oleracea) in West Shoa of Oromia, Ethiopia

Cabbage is Ethiopia's second most significant vegetable crop after red pepper (Capsicum spp), although its yield and yield components are influenced by a variety of factors, including cabbage aphids, which are a major pests in most of Ethiopia's cabbage-growing areas. This study was conducted to evaluate a newly introduced chemical insecticide (Kanthion 50% E.C), and locally available botanicals. Each treatment was replicated three times and the entire setup was arranged in a randomized complete block design (RCBD) under field conditions. In the field, among the botanicals tested, N. tabacum, A. sativum, and lemon extract resulted in the highest percentage of nymphs and adult mortality greater than 65% within three days after application. In the field, non-treated control plants showed low yield as compared to the chemical, and botanical insecticide. The highest fresh weight (3.01 kg) was obtained from plants treated with Kanthion 50% E.C. This study indicates that Kanthion 50% E.C, N. tabacum, A. sativum, and Citrus limon could be recommended as an alternative management option against Brevicoryne brassicae (L) under field conditions.

Plant‐Based Products as Control Agents of Stored Product Insect Pests: Prospects, Applications and Challenges

Stored product insect pests pose a significant threat to global food security and economic stability, as they cause substantial damage to stored grains and other food commodities. Traditional pest control methods often rely on chemical insecticides, which can have adverse effects on the environment, human health, and food safety. In light of these concerns, there is growing interest in exploring sustainable and eco-friendly alternatives for managing stored product insect pests. This abstract highlights the potential of plant-based products as a viable and environmentally friendly approach to control stored product insect pests. Plant-based products, such as botanical extracts and essential oils, are derived from various plant sources and have shown promise in repelling, deterring, and even killing insect pests. These products offer several advantages, including biodegradability, reduced chemical residues, and minimal harm to non-target organisms. This review summarizes recent research on the efficacy of plant-based products against a range of stored product insect pests, including but not limited to beetles, weevils, and moths. It discusses the mechanisms through which these products exert their pest control effects, such as disrupting insect behavior, affecting their reproduction, or inducing mortality. Moreover, the potential synergistic effects of combining plant-based products with other pest management strategies, like hermetic storage and modified atmospheres, are explored. In addition, this abstract examines the challenges and limitations associated with the use of plant-based products in pest management, including issues related to formulation, stability, and the need for further research to standardize application protocols. The economic feasibility and scalability of plant-based pest control methods are also considered. The findings presented in this abstract emphasize the importance of incorporating plant-based products into integrated pest management strategies for stored product insect pests. These products have the potential to contribute to a more sustainable and environmentally friendly approach to safeguarding global food reserves, while minimizing the risks associated with chemical pesticides. Further research and collaboration between the scientific community, agricultural industry, and policymakers are essential to harness the full potential of plant-based products in the fight against stored product insect pests.

A Study of the Toxic Effect of Plant Extracts against Philaenus spumarius (Hemiptera: Aphrophoridae).

The meadow spittlebug Philaenus spumarius (Hemiptera: Aphrophoridae) is distributed in several habitats worldwide and has been recently recognized as the main vector of Xylella fastidiosa subsp. pauca. This bacterium has been associated with olive quick decline syndrome (OQDS) in the Salento Peninsula (Italy) and is responsible for extensive desiccation and die-off of olive trees. Current OQDS management strategies include the control of P. spumarius populations, mainly through the removal of weed hosts and insecticide treatments. In addition to the mandatory phytosanitary measures, the demand for new strategies compatible with integrated pest management is increasing. In this study, laboratory biological assays were performed to assess the potential toxic effect of vegetal formulations against P. spumarius adults. Two formulations were tested at different concentrations: Form A, an emulsion of 10% hot pepper-infused oil (Capsicum annuum subspecies Cayenna in olive oil) and Arabic gum in an aqueous solution of extracts of Salvia guaranitica, and Form B, an aqueous solution of extracts of Taxus baccata. Both Form A and B showed to be toxic against P. spumarius compared to the water control. The mean percentage of spittlebug mortality obtained with Form A one hour after treatments was dose-dependent; the lethal dose values were 0.13% (LD25), 0.36% (LD50), and 0.85% (LD75). At the same time, no significant differences in mortality rate were observed between the 0.75% treatment and the treatments with deltamethrin (about 90%). The mean percentage of spittlebug mortality obtained with Form B ranged from 21% to 53% one hour after treatment, but these values were significantly lower than those obtained with deltamethrin. The effectiveness of Form A on the P. spumarius population was also evaluated in the field. The averages of captures in the three experimental blocks were 1.8/trap for treated and 7.7/trap for untreated plots, and the spittlebug populations significantly decreased after treatments. Based on these results and the literature data, we hypothesize that the effectiveness of Form A is the result of the synergistic effect of all its components. No symptoms of phytotoxicity were recorded on olive trees treated with Form A, and the number of P. spumarius specimens collected on these plants was much lower than on untreated plants. These results suggest the potential use of Form A in the protection of olive trees. This vegetal formulation can thus be considered as a valid alternative to chemical insecticides for the control of the main vector of X. fastidiosa and could be integrated into a sustainable management system for OQDS.

β-tubulin functions in spermatogenesis in Lygus hesperus Knight

Lygus hesperus Knight is an important insect pest of crops across western North America, with field management heavily reliant on the use of chemical insecticides. Because of the evolution of resistance to these insecticides, effective and environmentally benign pest management strategies are needed. Traditional sterile insect technique (SIT) has been successfully employed to manage or eradicate some insect pests but involves introducing irradiated insects with random mutations into field populations. New genetically-driven SIT techniques are a safer alternative, causing fixed mutations that manipulate individual genes in target pests to produce sterile individuals for release. Here, we identified seven β-tubulin coding genes from L. hesperus and show that Lhβtub2 is critical in male sperm production and fertility. Lhβtub2 is expressed primarily in the male testes and targeting of this gene by RNA interference or gene editing leads to male sterility.

Intercropped Flemingia macrophylla successfully traps tea aphid (Toxoptera aurantia) and alters associated networks to enhance tea quality.

The tea aphid, Toxoptera aurantia is a destructive pest causing severe damage to the quality and yield of tea, Camellia sinensis. Relying on chemical insecticides to control this pest causes adverse ecological and economic consequences. Trap plants are an eco-friendly alternative strategy to mitigate pest damage on focal plants by attracting target insects and natural enemies. Yet, the utilization of trap plants in tea plantations remains limited. Besides, the effects of the trap plant on the tea aphid-ant-predator community and tea quality and yield are unknown. Intercropped Flemingia macrophylla successfully trapped tea aphids and enhanced the complexity of aphid-ant-predator networks over three consecutive years compared to monoculture management. Moreover, F. macrophylla significantly increased the abundance of natural predators by 3100% and species richness by 57%. The increasing predators suppressed the aphid population and hampered its spillover to neighbouring tea plants. Consequently, F. macrophylla improved tea quality by an 8% increase in soluble sugar and a 26% reduction in polyphenols to amino acids ratio. The study illustrated that F. macrophylla is a suitable trap crop for tea aphid control in tea plantations. This legume increases species nodes and strengthens multiple connections in aphid-associated communities through its cascade effects, improving tea quality. These findings shed light on the potential application of trap plants in tea plantations as an efficient integrated pest management (IPM) strategy. © 2023 Society of Chemical Industry.

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.

Evaluation of augmentative biological control options against fruit and shoot borer, Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) in guava in India

BackgroundConogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) has emerged as one of the important pests of guava in Punjab, India. Chemical insecticides have been used for its management, which could have serious implications on environmental and human health. As an alternative to chemical insecticides, biocontrol is the most appropriate alternative for its eco-friendly management. Two field experiments were therefore, conducted to evaluate efficacy of two biocontrol agents, Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) (egg parasitoid) and Chelonus blackburni Cameroon (Hymenoptera: Braconidae) (egg-larval parasitoid) against the borer during rainy season, 2020 and winter season, 2020–21.ResultsFour releases of both parasitoids at various dosages were carried out at weekly intervals starting from first week of July in rainy season and first week of October in winter season. Trichogramma chilonis @ 2000 parasitized eggs per tree was the best in reducing the fruit damage and increasing yield and net income over check in both rainy as well as winter season crops. There was 73.6% reduction in damage over control, 1.70 Metric tons (MT) increase in yield over control and 258.36 US $ per acre increase in net income over control in rainy season crop. During winter season, there was 62.5% reduction in damage, 1.98 MT increase in yield and 488.23 US $ per acre increase in net income over control.ConclusionFour augmentative releases of T. chilonis @ 2000 parasitized eggs per tree successfully controlled the fruit and shoot borer incidence in guava during rainy and winter season.

Comparative Study of Cat’s Whiskers Leaves (Orthosiphon stamineus) and Mint Leaves (Mentha arvensis) as Repellent For Houseflies

House flies (Musca domestica) are one of the challenging pests that are difficult to overcome and control. Common control methods usually involve the use of chemical insecticides, but a more environmentally friendly alternative is to use plant-based insecticides with repellent properties. Medicinal plants from the Lamiaceae family are famous for their distinctive aroma and are effective in treating pest problems. This research aims to evaluate the potential of cat's whisker leaves and mint leaves as housefly repellent. The repellency test used cotton impregnated with extract concentrations of 2,000 ppm, 4,000 ppm, 6,000 ppm, 8,000 ppm and 10,000 ppm. Exposure time was 30 minutes and carried out 3 times. The repellency percentage is then calculated. The results of the research showed that at concentrations of 2,000 ppm and 4,000 ppm there were still some flies landing, but at concentrations of 6,000 ppm, 8,000 ppm and 10,000 ppm no flies landed. Strong repulsion was observed at concentrations of 2,000 ppm (86.7% for cat's whisker leaf extract and 82.7% for mint leaf extract) and 4,000 ppm (96% for cat's whisker leaf extract and 88% for mint leaf extract). Both extracts showed very strong repulsion (100%) at concentrations of 6,000, 8,000 and 10,000 ppm. These results show that the higher the concentration, the stronger the repellent effect produced. In conclusion, cat's whiskers and mint leaves have potential as active mosquito repellent ingredients, and this research can be the basis for further development as a pest control method, especially against houseflies.

Spinosad‐infused biodegradable hydrogel beads as a potential organic approach for argentine ant, Linepithema humile (Mayr) (hymenoptera: Formicidae), management in California citrus orchards

AbstractArgentine ant, Linepithema humile (Mayr), disrupts biological control services in California citrus orchards, leading to economically damaging densities of honeydew‐producing hemipteran pests. With the elimination of chlorpyrifos, the sole registered insecticide for L. humile control in California citrus, the development of effective alternatives is necessary. One alternative is aqueous sugar baits laced with minute concentrations (0.0001%) of insecticide. Field trials were conducted to assess the efficacy of spinosad and thiamethoxam‐infused alginate hydrogel beads (HGBs) for L. humile control. Thiamethoxam‐infused HGBs have previously shown high efficacy against L. humile in citrus. Spinosad is approved for organic use, while thiamethoxam, a neonicotinoid, along with other neonicotinoid insecticides, might soon face deregistration in California, underscoring the need for alternative insecticide chemistries for ant control. Therefore, this study aimed to optimize spinosad‐loaded HGBs by identifying efficacious concentrations, application rates, and deployment frequency, and to compare with thiamethoxam‐infused HGBs, the standard reference treatment. Results showed that spinosad‐infused HGBs significantly reduced high‐density L. humile populations in citrus orchards. Notably, the highest spinosad concentration tested (0.01%) demonstrated comparable control to both 0.0001% and 0.01% thiamethoxam concentrations. A tri‐weekly application schedule for spinosad‐infused HGBs provided best control. Trees treated with 125 or 250 g of hydrogels infused with 0.01% spinosad at weeks 0, 3, and 6 displayed significantly reduced ant activities compared to plots treated solely during weeks 0 and 6, as well as control plots lacking HGB applications. Spinosad‐infused HGBs may offer an effective alternative to thiamethoxam‐infused HGBs for control of L. humile in California citrus orchards.

Effects of repeated afidopyropen treatment on the structure and function of the soil microbial community

Chemical insecticides are the most effective pest control agents. Afidopyropen is a novel insecticide used against sap-sucking insects, such as aphids. However, the effects of repeated afidopyropen application on the structure and function of soil microorganisms remain unknown. In this study, the changes in the enzyme activities, community structure and function, and relative abundance of antibiotic resistance ontology (ARO) of soil microorganisms were investigated during three repeated afidopyropen applications under laboratory conditions at the maximum recommended dosage (M1) and 10 times the M1 (M10). The neutral phosphatase (NPA) and catalase (CAT) activities in the soil were significantly suppressed after afidopyropen treatment. The Simpson diversity index (1/D) and Shannon–Wiener diversity index (H) also decreased in both the M1 and M10 afidopyropen-treated soils, indicating a remarkable decrease in soil microorganism diversity. The average well color development (AWCD) first increased and subsequently recovered to normal levels after the third application of the insecticide, suggesting that afidopyropen application could increase the metabolic activity of soil microorganisms. Metagenomic analysis showed that repeated afidopyropen application in both the M1 and M10 treatment groups altered the community structure of soil microorganisms, albeit in different ways. Furthermore, repeated afidopyropen application significantly increased the relative ARO abundance, especially in the M10 treatment, with the most dominant AROs being adeF, baeS, and IND-6. These findings reveal the effects of excessive afidopyropen application on soil microorganisms and lay an important foundation for the comprehensive evaluation of the impact of this insecticide on the environment.

Modeling the effects of baculovirus to control insect population in agricultural fields

Baculoviruses are special kind of pathogens that attack insects and thus have a potential to reduce the density of insect population in agricultural fields and may be an alternate to chemical insecticides. In this work, we present a model consisting of non-linear differential equations to assess the effects of baculovirus as a bio-insecticide on insect population and thus crop production. In the modeling phenomenon, we consider one-time spray per season. It is shown that under certain conditions, one-time spray is sufficient to form self-sustained cycle of baculovirus replication in the agriculture fields. For the formulated model, the equilibrium solutions are obtained and their stability behavior is discussed. It is observed that parameters related to virus infection rate and virus replication rate are important to reduce the density of insects and increasing crop production. This study reveals that in the case of one-time spray, to achieve the stability of interior equilibrium solution, the infection rate must lie within its two threshold values. The effect of some other parameters on the dynamics of insect population and crop production is also shown by means of numerical simulation.