Influence of Chlorpyrifos-methyl on the Biochemistry of Haemo-lymph and Fat Body of the Larva of Almond Moth, Ephestia cau-tella Walker (Lepidoptera: Pyralidae)

Abstract

The almond moth, Ephestia cautella Walker larvae cause serious damage to wheat, maize, peanuts, pulse, cocoa beans, dried fruits etc. The haemolymph and fat body play major roles in the insect developmental physiology. Proteins and amino acids are important biochemical constituents of haemolymph and fat body of the insects. Changes in the total protein and total free amino acids level were studied in the haemolymph and fat body of third instar larvae of almond moth exposed to sublethal concentrations of chlorpyrifos-methyl. The sublethal concentrations i.e. 1, 2 and 4 ppm of chlorpyrifos-methyl caused a significantly dose-dependent reduction in the level of total protein and an associated enhancement in the total free amino acids level in haemolymph and fat body tissue of the E. cautella larvae. The maximum decrease in total protein level in haemolymph (37% of the control value) and fat body (46% of the control value) was observed in larvae treated with 4 ppm of chlorpyri- fos-methyl. The maximum enhancement in the total free amino acids level in haemolymph (175% of the control value) and fat body (172% of the control value) was observed in larvae treated with 4 ppm of chlorpyrifos-methyl. The imbalances of bio- chemical constituents resulted abnormalities in developmental physiology such as retention of old cuticle, lethargy, lose of body fluids and death.