Comparative efficacy of Dichlorvos and dimethoate against two major sucking pests of tapioca.

摘要

The comparative efficacy of Dichlorvos and dimethoate solely and in combination with neem oil and fish oil rosin soap (FORS) against spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) and papaya mealybug, Paracoccus marginatus Williams Granara de Willink (Hemiptera: Pseudococcidae) infesting tapioca (Manihot esculenta Crantz), the food plant of eri silkworm (Samia cynthia ricini Boisduval) was assessed under field condition. The synergistic effect of dimethoate (0.05%) with neem oil (3%) as well as FORS (2%) have been found equally promising with highest reduction in population of spiralling whitefly (85.37 & 85.14%) and papaya mealybug (81.00 & 80.10%) than its sole application (76.18 & 70.16%) and when compared to the respective treatments of dichlorvos against spiralling whitefly (78.17 & 73.58 and 64.91%) and papaya mealybug (69.35 & 66.88% and 52.49%). These combinations also recorded highest leaf yield i.e. 669.73 & 672.16 g/plant and 655.94 & 657.27 g/plant in the plots treated against spiralling whitefly and papaya mealybug respectively than other treatments, over control (515.30 & 478.63 g/plant) and may be used to manage both the pests successfully in tapioca garden.