Demographic Comparison of Henosepilachna vigintioctopunctata (F.) (Coleoptera: Coccinellidae) Reared on Three Cultivars of Solanum melongena L. and a Wild Hostplant Solanum nigrum L.

Henosepilachna vigintioctopunctata (F.) is a widespread pest found on many solanaceous vegetables. The development and fecundity of H. vigintioctopunctata were studied on three cultivars ('Zihong', 'Eyou', and 'Baijiao') of eggplant, Solanum melongena L., using the two-sex life table theory. These results were then compared with similar parameters from a wild alternate host, Solanum nigrum. Our results showed that there were no significant differences between the developmental times of the larval stages, pupae, oviposition period, adult longevity, and the fecundity of H. vigintioctopunctata reared on the three eggplant cultivars. The survival rates of H. vigintioctopunctata larvae reared on the three eggplant cultivars were higher than that on S. nigrum. The fecundity of H. vigintioctopunctata adults reared on S. nigrum (724.12 eggs), however, was significantly higher than on each of the three eggplant cultivars. The values for the intrinsic rate of increase (r), finite rate of increase (lambda), and net reproductive rate (R-0) for H. vigintioctopunctata when reared on S. nigrum were 0.1225 d(-1),1.1303 d(-1), and 299.6 offspring, respectively. Each of these was significantly higher than comparable values when reared on the cultivar Eyou and Baijiao but were not different from those reared on the Zihong. Our results indicated that H. vigintioctopunctata is well adapted to all tested host plant cultivars and that S. nigrum is an important alternate wild hostplant that may potentially contribute to future outbreaks of H. vigintioctopunctata if not taken into consideration when planning an integrated control strategy against the pest.