Abstract:

Asian longhorn beetle larvae were fed on host plants and artificial diet to investigate the variation of cellulase, and the activity of exoglucanase and β-glucosidase were measured. The results showed that larvae fed on host tree under natural growth situation had a significant reduction in both endoglucanase and β-glucosidase activities. The activity of endoglucanase in the first and second instars was higher than the followed three instars, and the activities of β-glucosidase in the former three instars are higher than the followed two instars. This trend also occurred in the larvae fed on artificial diet. The activity of endoglucanase in the 10, 20 and 30 days of age larvae was higher than that in the 80, 100 and 120 days of age larvae, and the activities of β-glucosidase reached a peak in the 60 days of age larvae, higher than the 80, 100 and 120 days of age larvae. Therefore it is suggested that ecological control measures related to cellulase inhibitor should be carried out on the first two instars larvae. According to its biological characteristics, the best time for controlling through inhibiting the activity of cellulase would be from September to November.

Key words: enzyme activity, host tree, artificial diet, instars, days of age