Abstract: Results of experiments performed from 1982 to 1984 to control the whltefly with P. fumosoroseus var. beiJingensis on cucumber in greenhouses in Beijing showed a 71-100% effectiveness. Under the greenhouse conditions with the mean temperature ranging from 15.6-21.3°C and 79-93% RH, three applications of the fungous spores at 10 to 14 days interval, beginning from the initial fruiting stage, resulted in an average of 40% adult suppression. The infection rate for nymphs, pupae and adults were 81%, 63% and 41%, respectively. The population growth index for the peat was O.4 throughout the 70-day experiment.