Comparative Toxicity of Profenofos and Lufenuron to Silkworm (Bombyx Mori L.) Under Different Methods of Application

Silkworm is an oligotrophic silk spinning insect with high economic value, feeding on Mulberry leaves, which are the most suitable natural foods for this insect. In recent years, pesticide poisoning of silkworms has occurred from time to time and pose a serious threat for Bombyx mori cultivation. In the present study, the lethal effect of Profenofos and leufenuron against the early three molts of silkworm immatures was evaluated using two different application approaches, i.e., leaf dip and spraying on one side of the leaf. Results showed that among the tested insecticides, Profenofos had a notable effect on the tested insect. LC50 values, i.e., 0.111, 1.479, and 0.203 μL/liter have been observed against 1st, 2nd, and 3rd instars, respectively, in response to Profenofos exposure by the leaf dip method. For the 2nd methodology, the LC50 values recorded were 0.401, 1.47, and 3.42 μL/L in the first three molts. LC 50 value for 1st instar larvae was 9.195 for leufenuron when the leaf dip method was adopted, and 20.724 uL/Liter when the insecticide concentration was sprayed on one side of a leaf. Results showed that Profenofos can significantly reduce the population of B. mori as compared to leufenuron. Overall, the leaf dip methodology yielded significantly better results compared to the second method (spraying). The obtained information could help the sericulture industry avoid fields with a risk of Profenofos exposure, as it has lower LC50 values.