Abstract:

In order to explore the larval damage of Spodoptera exigua on different host plants, Chenopodium album L., Amaranthus mangostanu, Beta vulgaris and Allium fistulosum L. were assessed by selection tests feeding preferences and the nutritional utilization of S. exigua. The results indicated that the preference of 1st instar larva to the four plants was C. album L., A. mangostanu, B. vulgaris and A. fistulosum L.. Feeding preference of the 3rd instar larva was not as obvious as the 1st instar larva. And the host plant feeding preference of 3rd instar larva was weakened with the prolonged observation period. The nutrition indexes of 3rd instar larvae on consumption of the four host plants indicated that the relative growth rate (RGR) and efficiency of conversion of digested food (ECD) in larva feeding on B. vulgaris was significantly higher than that on the three plants; the relative consumption rate (RCR) and approximate digestibility (AD) in larva feeding on A. fistulosum L and the efficiency of conversion of ingested food (ECI) in larva feeding on C. album L. was the highest. 3rd instar larva can seriously harm the B. vulgaris and A. fistulosum L.. Therefore, in the process of operation in agriculture, the 3rd instar larvae should be strengthened monitoring and management.