Host stage preference and suitability of Allotropa suasaardi Sarkar & Polaszek (Hymenoptera: Platygasteridae), a newly identified parasitoid of pink cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae)

Allotropa suasaardi Sarkar & Polaszek (Hymenoptera: Platygasteridae) has been recently reported as a gregarious endoparasitoid of the pink cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae) in Thailand. With the aim of improving mass production of this parasitoid, laboratory experiments were conducted comparing the parasitoid’s preference on different host stages of mealybug, host suitability and its effect on parasitism, development, progeny fitness and sex ratio. All nymphal stages and adult of P. manihoti were parasitized by the parasitoid. However, host stage preference and suitability tests showed that the parasitoid had a significant preference for the older host stages. Percentage parasitization was higher in the third instar and early adult female stages compared with the first and second instar host. Mean developmental time for male parasitoids was shorter than for the females. Higher percentage emergence of parasitoid was observed from older mealybugs. Sex ratios of the offspring produced by the parasitoid were varied in different host stages and the ratio of female to male was higher in the older host stages. The implication of this host selection behavior for mass rearing of A. suasaardi and for evaluating it in a biological control program of the cassava mealybug are discussed.