Effect of an extracted lectin from Sclerotinia sclerotiorum de Bary on mortality and physiological parameters in the larvae of large cabbage butterfly, Pieris brassicae (Lepidoptera: Pieridae)

In the current study, the extracted lectin from plant pathogenic fungus, Sclerotinia sclerotiorum was added to diet of third larval instars of Large cabbage butterfly, then its effects were determined on mortality, feeding and intermediary metabolism. Concentrations of 0.5, 1 and 2 mg/ml of the lectin caused 20-60% of mortality in the treated larvae. Amounts of nutritional indices in the treated larvae significantly decreased versus control although level of Metabolic cost in the treated larvae showed statistical increase versus control. Activities of the digestive enzymes such as alpha-amylase, glucosidases, lipase, general and specific proteases (Serine and Exopeptidases) decreased in the fed larvae on lectin concentrations versus control. Although activities of aspartate aminotransferase and γ-glutamyl transferase significantly increased in the concentrations of 1 and 2 mg/ml but activity of alanine aminotransferase had a significant decrease versus control. Activity of acid phosphatase had no statistical differences among treatments and control but activity of alkaline phosphatase was significantly lower than control larvae. Activity of lactate dehydrogenase in the fed larvae on the concentration of 2 mg/ml had significant increase but activities of aldolase in the control and fed larvae on 0.5 mg/ml of lectin were higher than those of other treatments. Amounts of storage macromolecules such as protein, triglyceride and glycogen in the fed larvae on the lectin were lower than those of control so that it was more significant in the concentration of 2 mg/ml. Results of the current study demonstrated that the lectin from S. clerotiorumcaused mortality and interference in digestive physiology and intermediary metabolism of P. Brassicae larvae so it could be used as a toxic molecule to control of the pest.