Effect of some fungicides on Spodoptera litura (Fabricius) by artificial diet incorporation method
Loading...
Date
2004-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera : Noctuidae) is a polyphagous pest. This insect pest is widely distributed throughout India. This pest has constant association with many agricultural crops causing losses to pulses, oilseeds and vegetables and is widely distributed in South East Asia. Now-a-days large scale use of synthetic organic insecticides to control this pest result in development of resistance against insecticides belonging to different groups. Therefore, to overcome the problems of insecticidal resistance, pest management, secondary outbreaks of pests due to indiscriminate use of pesticides, a need is felt for adopting an ecofriendly IPM programme of S. litura. In order to manage both insects and fungus and as a part of IPM programme, attempts were made to investigate the effect of fungicides on the developmental profile of S. litura. In addition, attempts were made to understand toxicity of fungicides on this insect. Six commonly used fungicides were tested. They were Bavistin 50 WP (carbendazim) (0.2, 0.1, 0.005, 0.025, 0.0125 and 0.00625 percent), Thiram 75 WP (0.4, 0.2, 0.1, 0.05, 0.025 and 0.00125 percent), Matco 72 WP (Metalaxyl 8 percent + Mancozeb 64 percent) (0.4, 0.2, 0.1, 0.05, 0.025 and 0.0125 percent), Sulfex 80 WP (sulphur) (0.4, 0.2, 0.1, 0.05, 0.025 and 0.0125 percent), Vitavax 75 WP (carboxin) (0.4, 0.2, 0.1, 0.05, 0.025 and 0.0125 percent), Captan 83 WP (0.4, 0.2, 0.1, 0.05, 0.025 and 0.125 percent) were tested by artificial diet incorporation method. The levels of fungicides tested were two doses above and three doses below the recommended field dose. Various concentrations of above fungicides were prepared by serial dilution method. This experiments were conducted at 28 + 10C temperature and 75 + 5 r.h. Observations were recorded on larval survival at 24 hr interval, are larval period, pupal period, percent pupation and percent adult emergence. From three observations growth index and success index were computed. Data recorded on larval mortality caused by fungicides were subjected to probit analysis. Larval period is not significantly prolonged for Bavistin and Captan. But significantly prolonged for Vitavax, Matco, Sulfex and Thiram than artificial diet alone. Pupal period is not significantly prolonged for all fungicides tested except captan and thiram as compared to artificial diet alone. Percent pupation significantly reduced for all fungicides. Based on initial population, adult emergence significantly reduced for all fungicides. Growth and success indices are also lowered for all fungicides diets (except 0.4 % sulfex and 0.4 % thiram) than artificial diet alone indicating inferiority of tested diets over control. LC50 ranged from 0.048 to 6.64 for Bavistin, 0.07 to 1.14 for Vitavax, 0.15 to 0.30 for Matco, 0.02 to 0.19 for Captan, 0.097 to 0.06 percent for sulfex and 0.057 to 0.06 for Thiram when, calculated on the bases of above three parameters. Comparison of six fungicides on the bases of LC50 on a specific day revealed the order of toxicity as Thiram = Sulfex > Captan > Matco > Vitavax > Bavistin.
Description
Keywords
null