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

Comparative Evaluation of Biopesticides for the Management of Leucinodes orbonalis Infesting Brinjal

Brinjal shoot and fruit borer, Leucinodes orbonalis, is a major pest of brinjal that causes serious damage to shoots and fruits. This field study evaluated the relative efficacy of selected biopesticides and biorational insecticides against L. orbonalis during the Kharif season of 2023 at the College of Agriculture, Hassan. The experiment was laid out in a randomised block design with eight treatments and three replications. The treatments comprised Metarhizium rileyi, Beauveria bassiana, azadirachtin 1,500 ppm, Metarhizium anisopliae, azadirachtin 10,000 ppm, spinosad 45% SC, chlorantraniliprole 18.5% SC as the standard check, and an untreated control. Two sprays were applied: the first at the initiation of infestation and the second 15 days later. Shoot infestation was recorded 3, 7, and 14 days after each spray, whereas fruit infestation was recorded at harvest. Chlorantraniliprole recorded the lowest pooled shoot infestation (2.78%) and fruit infestation (17.26%). Among the tested biopesticide and biorational treatments, spinosad recorded the lowest pooled shoot infestation (3.72%) and fruit infestation (19.06%), followed by azadirachtin 10,000 ppm. Entomopathogenic fungi were less effective than spinosad and azadirachtin but performed better than the untreated control. The findings indicate that spinosad and azadirachtin may be useful components of an integrated management programme for L. orbonalis.

INSECTICIDAL ACTIVITY OF Mentha × piperita L. (LAMIACEAE) ESSENTIAL OIL ON THE DEVELOPMENT OF THE COTTON STAINER BUG DYSDERCUS PERUVIANUS HEMIPTERO (PYRRHOCORIDAE)

Cotton (Gossypium hirsutum L.) is a crop of high economic importance; however, it is severely affected by insect pests, particularly Dysdercus peruvianus (Hemiptera: Pyrrhocoridae). The reliance on synthetic insecticides highlights the need for safer and more sustainable alternatives. This study evaluated the insecticidal potential of Mentha × piperita L. essential oil against biological parameters of D. peruvianus. Fourth-instar nymphs were subjected to contact and topical treatments at different concentrations and monitored for up to 28 days to assess mortality, development, adult emergence, reproductive performance, and morphological alterations. The essential oil showed concentration-dependent toxicity in both exposure routes. In the contact treatment, pure oil and 156.2 µg/cm² caused complete mortality within 48 h, whereas 78.1 µg/cm² promoted progressive population elimination. In the topical treatment, pure oil and 451.5 mg/mL caused complete mortality within the first 24 h. Development was impaired, reducing adult emergence to less than 5%. Reproduction was also affected, with complete inhibition of oviposition at 19.5 µg/cm² and reduced egg-laying in the remaining treatments. In addition, morphological deformities were observed in surviving individuals, indicating interference with normal development. These findings demonstrate that M. × piperita essential oil is a promising botanical insecticide with potential for the integrated management of D. peruvianus, contributing to more sustainable pest control strategies while reducing environmental impacts.

Efficacy of bio-rational insecticides against major rice pests under field conditions in South Sulawesi, Indonesia

The brown planthopper (Nilaparvata lugens), green leafhopper (Nephotettix virescens), and yellow stem borer (Scirpophaga incertulas) are among the most destructive insect pests of rice in Indonesia. This study evaluated the field performance of four biorational insecticides (abamectin, azadirachtin, Beauveria bassiana, and Metarhizium anisopliae) and two synthetic insecticides (carbofuran and demihipo) in a rice field in Belawa, Wajo Regency, South Sulawesi, Indonesia. The experiment was arranged in a split-plot randomized complete block design. All biorational insecticides significantly reduced pest populations compared with the untreated control. Abamectin provided the greatest suppression of N. lugens (84.1%), whereas abamectin, carbofuran, and demihipo were the most effective treatments against N. virescens, reducing populations by 71.8%, 69.2%, and 82.4%, respectively. Against S. incertulas, azadirachtin and abamectin achieved the highest reduction in dead-heart incidence (91.9% and 85.7%, respectively). Predator populations, particularly Coccinella spp., were largely conserved in plots treated with azadirachtin, B. bassiana, and M. anisopliae, indicating good compatibility with beneficial arthropods. Weekly applications provided pest suppression comparable to twice-weekly applications, suggesting that insecticide inputs can be reduced without compromising efficacy. Overall, the findings demonstrate that biorational insecticides can be effectively integrated into rice IPM programs to suppress major pests, conserve beneficial arthropods, and reduce reliance on conventional synthetic insecticides, thereby supporting more sustainable rice production.

Efficacy of Newer Insecticides against Sucking Pests of Black Gram (Vigna Mungo L.)

Afield experiment was carried out to evaluate the efficacy of some newer insecticide molecules against major sucking pests on black gram and their impact on associated natural enemies and incremental benefit. Out of twelve treatments tested, ten were from novel groups including spinetoram, flonicamid, diafenthiuron, pyriproxyfen, spiromesifen, dinotefuran, clothianidin, cyantraniliprole, fipronil and pymetrozine. Whitefly, leaf hopper, aphid and flower thrips were recorded as major sucking pests. Diafenthiuron emerged as the most effective insecticide against whitefly (97.7% reduction), leaf hopper (91.2%) and aphid (96.2%) and yielded the highest (1208.33 kg ha-1). Fipronil significantly controlled flower thrips (86.2%) as compared to other treatments. All the tested treatments did not show any detrimental impact on associated natural enemies. Clothianidin treated plots resulted in highest incremental cost benefit ratio (1:25.8) followed by flonicamid (1:18.7), dinotefuran (1:16.7) and diafenthiuron (1:15.6), highlighting their economic feasibility in integrated management program.

Field evaluation of biorational insecticides for managing major rice pests and conserving natural enemies in South Sulawesi

Compatibility and Efficacy of Insecticides and Fungicides for Integrated Pest and Disease Management in Urdbean (Vigna mungo)

The productivity of urdbean (Vigna mungo L. Hepper) in India faces significant challenges from insect pests and diseases, resulting in substantial yield losses. This study evaluated the efficacy and compatibility of novel insecticides like thiamethoxam and spinosad and a fungicide, propiconazole for the integrated management of sucking pests (aphids, whiteflies) and diseases (Yellow Mosaic Virus, Cercospora Leaf Spot) in urdbean under kharif upland conditions. Field research trials demonstrated that combined applications significantly reduced pest populations and disease severity without causing phytotoxicity, leading to higher yields. Thiamethoxam 25 WG + propiconazole 25 EC recorded the highest pest reduction (up to 82.7% for aphids, 75% for whiteflies) and disease control (72.4% for CLS), resulting in a yield increase of 87.8% overcontrol. The treatment including thiamethoxam 25 WG + propiconazole 25 EC registered the highest net return of Rs 16,955/- and the highest B:C ratio of 1.79. This cost-effective, compatible tank-mix approach provides a sustainable solution for resource-poor farmers, enhancing urdbean productivity and supporting food security.