Entomopathogenic fungi of the oil palm pest, Zophiuma butawengi (Fulgoromorpha: Lophopidae), and potential for use as biological control agents

Oil palm, Elaeis guineensisJacq., is an important cash crop in Papua New Guinea. Production is currently under threat from Finschhafen disorder caused by the planthopper Zophiuma butawengi (Heller), a native pest of coconut. The need for a non-chemical strategy to manage Z.butawengi is high because the industry is committed to sustainable production. One possible option is the development of biological control using entomopathogenic fungi, and this study aimed to assess the scope for such a technology. Field collections extending over three regions of West New Britain in the 2010 monsoon season yielded 38 mycosed cadavers. Only three yielded entomopathogenic fungi: two of Hirsutella citriformisSpeare and one each of Metarhizium flavoviride var. minusRombach, Humber and D.W. Roberts, and Purpureocillium lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones and Samson. The pathogenicity of each isolate to Z.butawengi was confirmed in a laboratory study. M.flavoviride var. minus killed Z.butawengi significantly more rapidly over the course of a 15-day period, and day 7 mortality was significantly greater than in water or nil control treatments. Given this pathogenic fungus was readily culturable and congenerics are used in other biological control treatments, it merits further investigation as a potential inundative entomopathogenic agent against Z.butawengi.