Effect of Sublethal Concentrations of Chlorothalonil on Weight Variations and Bioenergetic Resources of Colorado potato beetle Leptinotarsa decemlineata Say (Col.: Chrysomelidae)

The Colorado potato beetle (CPB) is the most important pest of potato. Adults and larvae feeding on potato leaves cause economically damage to host. Since this pest overwinters as adults in soil, any disturbance in assimilation and storage of the energy resources may weaken the overwintering adults and lessen their resistance to environmental stresses during the winter. In this research, effects of sublethal concentrations of Chlorothalonil 72% SC were studied on lipid, carbohydrate and protein contents in CPB adults under field conditions. The experiments had a complete randomized four-factor factorial design. The four factors were the concentration (0, 2000, 3000 and 4000 μl/l), sex (male and female), time (3, 6 and 12 day) and number of treatment (first and second). The sugar, glycogen and lipid quantities were determined in milligram per gram of fresh weight. Results showed that Chlorothalonil affected significantly the lipids, glycogens, sugars, proteins and caloric content (p<0.01). The most reductions in bioenergetic resources were observed in adults retreated with the concentration of 3000 μl/l 12 days after second Spraying. After taking into account the control, %61.07, %21.58, %57.22 and %54.46 reduction were found in lipid, glycogen, sugar and energy content, respectively. Also in concentration of 3000 μl/l protein increased as much as 39.94%. So the chlorthalonil reduced the outcome of energy in CPB.