Taro as an alternative food of cassava mealybug for mass rearing of the parasitoid Anagyrus lopezi

The cassava mealybug Phenacoccis manihoti (Hemiptera: Pseudococcidae) and its parasitoid Anagyrus lopezi (Hymenoptera: Encyrtidae) had been mass-reared with cassava or pumpkins. To seek alternative host plants for their mass rearing, we conducted laboratory experiments to determine suitability of the taro Colocasia esculenta (L.) (Alismatales: Araceae) for rearing them. Either 50 newly hatched mealybug nymphs or parasitized third-instar mealybugs were reared on taro or cassava seedlings to examine immature development, fecundity and longevity of adults. Nearly 90% of P. manihoti reared on taro successfully developed to adults and they produced 230 eggs on average in their lifetime, while insects reared on cassava showed 95% survival and 250 eggs of lifetime fecundity. Anagyrus lopezi is a koinobiont species, and the cassava mealybug nymphs parasitized by A. lopezi continued to feed on plants for 10 days on taro and cassava. Of parasitized cassava mealybug nymphs fed on taro 86% yielded parasitoid adults. The emerged parasitoid females laid 140 eggs in their life time on average. The immature survival and fecundity of parasitoids on taro was comparable to 88% of immature survival and 140 eggs of fecundity on cassava. Our results showed that the taro can be used as an alternative host plant for rearing P. manihoti that are healthy or parasitized by the koinobiont parasitoid A. lopezi.