Abstract:

In order to illustrate the effects of different plant hosts on nutritional utilization and activity of the carboxylesterase of the larvae Loxostege sticticalis L., L. sticticalis L. was fed respectively with Chenopodium album L., Glycine max L., Medicago sativa L., Beta vulgaris L., Helianthus annuus L.. The results showed that there were significant differences in the nutrient status and activity of the carboxylesterase of the insect fed with five different plants. The relative growth rate (RGR=0.91) and the approximate digestibility (AD=63.89%) of 3th instar larvae fed with the lambsquarter were significantly higher than those with the soybean, alfalfa, sugarbeet and sunflower. The efficiency of conversion of ingested food (ECI=24.65%, 24.96%) and the efficiency of conversion of digested food (ECD=38.70%, 41.41%) had no significant differences in larvae fed with the lambsquarter and soybean. The efficiency of conversion of ingested food (ECI=10.63%) and the efficiency of conversion of digested food (ECD=25.89%) of the larvae fed with alfalfa were significantly lower than those fed with the other four plants. Preliminary physiological reaction of testing 5th instar larvae showed that the contents of protein in haemolymph of the larvae fed with the soybean were significantly higher than those fed with the other four plants and the contents of protein in mid-gut of the larvae fed with the sunflower were the highest. The esterase in mid-gut of the larvae fed with the lambsquarter and soybean were significantly higher than those fed with the other three plants. The results suggested that lambsquarter was considered the most appropriate host, followed by soybean, sugarbeet, sunflower and alfalfa.