Insecticide Susceptibility and Toxicity against Pink Bollworm (Pectinophora gossypiella Saunders) Populations in Cotton

Status of insecticide resistance and detoxification enzymes activity in pink bollworm, Pectinophora gossypiella (Saunders) populations from India

Insecticide bioassays conducted across major cotton-growing regions of India revealed a notable increase in LC50 values in field populations compared to the laboratory-susceptible strain, confirming reduced susceptibility and development of resistance.

Comparative laboratory efficacy of three commercial organophosphate insecticides against fall armyworm (Spodoptera frugiperda) larvae

Fall armyworm, Spodoptera frugiperda, is a maize pest whose management remains dependent on synthetic insecticides. This study compared three organophosphate insecticides against third-instar S. frugiperda larvae. Chlorpyrifos, profenofos, and diazinon were evaluated at 5%, 20%, 50%, 75%, and 95% of the maximum label dose using a factorial completely randomized design with three replications of six larvae. Mortality was recorded for 168 h and corrected using Abbott’s formula based on pooled control mortality. Insecticide formulation significantly affected mortality (F₂,₃₀ = 39.06, P < 0.001), whereas concentration (F₄,₃₀ = 0.57, P = 0.687) and the insecticide × concentration interaction (F₈,₃₀ = 1.62, P = 0.162) were not significant. Across concentrations, profenofos and diazinon caused mean mortalities of 90.4% and 93.2%, respectively, and both were more effective than chlorpyrifos, which caused 32.2% mortality. Exploratory probit analysis estimated LC₅₀ values of 2.01% for profenofos and 0.71% for diazinon, but both were below the lowest concentration and had wide confidence intervals. Chlorpyrifos LC values were not estimable because its concentration–mortality slope was negative and non-significant. At 95% of the label dose, profenofos reached 50% corrected mortality within 24 h and diazinon within 48 h, whereas chlorpyrifos did not reach this threshold within 168 h. Profenofos and diazinon showed comparably high efficacy and outperformed chlorpyrifos.

Efficacy of botanical and biological inseccides against Spodoptera frugiperda in corn

Stage-specific Toxicity and Efficacy of Different Insecticides in the Management of White Grub (Brahmina coriacea)

Brahmina coriacea (Hope) is a prominent white grub species and a serious soil-dwelling pest, causing considerable damage to various agricultural and horticultural crops in the northwestern Himalayan region of India. The present study assessed the toxicity of selected insecticides against third-instar grubs, adults, and eggs of B. coriacea under laboratory conditions. Among the tested insecticides, chlorantraniliprole was the most effective across all life stages, recording the lowest LD50 values in grubs (1.41 μg per grub) and adults (0.23 μg per beetle), and the highest egg mortality (53.14%). Bifenthrin showed comparable toxicity to chlorantraniliprole in grubs, while carbofuran and chlorpyriphos exhibited moderate effectiveness; fipronil was consistently the least toxic. Adults were more susceptible than grubs, as indicated by lower LD50 values. Egg mortality increased significantly with exposure period, i.e. 18.43% at 3 days to 49.44% at 14 days after treatment, demonstrating a clear time-dependent effect. Overall, chlorantraniliprole emerged as the most potent insecticide against B. coriacea. The findings highlight the importance of considering life-stage differences in insecticide efficacy and provide a scientific basis for optimising pest management strategies targeting B. coriacea.

Assessment of insecticides and biopesticides against Myzus persicae (Sulzer) on Spinacia oleracea L.

The green peach aphid is one of the most destructive sucking insect pests infesting spinach. Field experiments were conducted at the Vegetable Research Farm, Rahuri, during the Rabi seasons of2020 and 2021 to assess the comparative evaluation of selected insecticides and biopesticides against this pest. Among the treatments evaluated, imidacloprid @ 30 g ai. ha -1 , thiamethoxam @ 25 g ai. ha -1 , dimethoate @ 300 g ai. ha -1 , and azadirachtin 1% @ 2 ml L -1 proved to be the most effective in suppressing green peach aphid populations. The highest spinach yields were recorded in plots treated with imidacloprid (16.11 t ha -1 ), followed by thiamethoxam (15.22 t ha -1 ). Similarly, the maximum incremental cost-benefit ratio was obtained with imidacloprid (1:76.49), followed by thiamethoxam (1:61.91).

Comparative toxicity of chlorantraniliprole and spinetoram against Spodoptera litura (Fabricius) under laboratory conditions

Spodoptera litura (Fabricius) is a destructive polyphagous pest of pulse crops, including green gram (Vigna radiata (L.) R.Wilczek), causing severe defoliation and significant yield losses. Identifying insecticides with high toxicity and rapid action is essential for effective management of this pest. The present study evaluated the comparative toxicity of chlorantraniliprole and spinetoram against 11 day old larvae of S. litura under laboratory conditions. Larval bioassays were conducted using the leaf-dip method and mortality was recorded at 12, 24, 48 and 72 hr after treatment (HAT). Probit analysis was performed to estimate lethal concentrations (LC) and compare the relative toxicity of the two insecticides. The toxicity of both insecticides increased with exposure time, as indicated by a progressive decline in LC₅₀ values. Chlorantraniliprole consistently exhibited greater toxicity than spinetoram throughout the study. At 24 HAT, chlorantraniliprole exhibited a substantially lower LC (0.008 %) than spinetoram (0.064 %), indicating approximately 8-fold greater toxicity. The difference in toxicity gradually decreased with prolonged exposure and both insecticides exhibited an identical LC₅₀ value (0.002 %) at 72 HAT, resulting in high larval mortality. Overall, both insecticides were effective against S. litura larvae. However, chlorantraniliprole produced faster and greater toxic effects than spinetoram. These findings support the use of chlorantraniliprole as a rapid-acting insecticide and highlight the potential of both molecules for the integrated pest management (IPM) of S. litura in green gram.