First Record of Isaria fumosorosea Wize (Deuteromycotina: Hyphomycetes) Infecting Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in Malaysia

Problems of efficacy and resistance manifested by whiteflies as consequences of chemical sprayings warrant a serious attention. Such hazardous outcomes call for an alternative method of controlling whiteflies that is safe to the produce, people and environment. In this study, efficacy of a newly isolated Isaria fumosorosea Wize infecting whitefly, Bemisia tabaci (Gennadius), from Universiti Putra Malaysia (UPM) was compared with isolates from bagworms, Pteroma pendula (Joannis) under laboratory conditions. All stages of B. tabaci were susceptible to infection by I. fumosorosea isolates when bioassayed at 1x10 super(6) mL super(-1). Among all the isolates tested, UPM isolate was the most virulent, causing 91, 90, 86 and 89% mortality on eggs and second, third and fourth instars, respectively. A concentration-mortality response test of the isolate on second instar nymphs resulted 95% mortality within 6 days when treated with 1x10 super(8) conidia mL super(-1). The results conclude that UPM isolate was the most effective against all stages of B. tabaci than those solates from other insects. Thus UPM isolate has the potential to be further developed as a biopesticide for controlling B. tabaci.