Host plants and natural enemies of papaya mealybug, paracoccus marginatus (Hemiptera: Pseudococcidae) in Thailand

Abstract

The papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) is native to Mexico and Central America. Between 2008 and 2009 it was detected variously in south India, Indonesia, Malaysia, Sri Lanka and Thailand. Field surveys of host plants of P. marginatus in Thailand between 2008 and 2010 revealed 10 species of host plants in 6 families: papaya, Carica papaya L. (Caricaceae): Lan Thom or plumerias, Plumeria acuminata Aiton and Plumeria rubra L. (Apocynacea); Ya Khon Cham Dok Khao or Spanish needles, Bidens pilosa L. and Bidens pilosa L. var. radiata Scherff (Compositae); Pattawia, Jatropha integerrima Jacq.: cassava, Manihot esculenta Crantz (Euphorbiaceae); Cha Ba or hibiscus, Hibiscus rosasinensis L. (Malvaceae); and Phut Sam Si or yesterday, today and tomorrow, Brunfelsia uniflora (Pohl) D. Don and Makhuea Phuang or Turkey berry or prickly solanum or devil's fig, (Solanum torvum Swartz) (Solanaceae). Eleven species of natural enemies were found: two parasitic insects, Anagyrus sp. and Anasius sp. (Hymenoptera: Encyrtidae); and ten predaceous insects, including five coccinellids, Cryptogonus orbiculus (Gyllenhal), Sasajiscymnus quinquepunctatus (Weise), Scymnus quadrillum Motschulsky, Scymnus sp., and Stethorus sp. (Coleoptera: Coccinellidae); a carnivorous apefly, Spalgis epius (Westwood) (Lepidoptera: Lycaenidae, Miletinae); two species of green lacewings, (Chrysoperla sp. (carnea group) and Mallada basalis (Walker) (Neuroptera: Chrysopidae); and an unidentified syrphid fly (Diptera: Syrphidae). Preliminary field observation indicated that the encyrtid, Anagyrus sp., the coccinellid, S. quinquepunctatus, and the apefly, S. epius, were dominant species in the natural enemy guild. These species should be investigated further as they may be useful in the augmentative biological control of P. marginatus in Thailand.