EVALUATION OF PETROLEUM SPRAY OILS FOR CONTROL OF THE ASIAN CITRUS PSYLLA, DIAPHORINA-CITRI (KUWAYAMA) (HEMIPTERA, PSYLLIDAE), IN CHINA

The efficacy of petroleum spray oil against citrus psylla was tested i n Guangzhou, China. As the oil concentration increased from 0.25% to 1 .0% there was a linear decrease in the number of psylla of each stage present on foliar shoots after 8 days. When psylla infested shoots wer e sprayed with equivalent oil concentrations, survival was significant ly different between oil treatments. Psylla survival was also stage-de pendent, with Ist-end instars being the most susceptible and eggs bein g the most tolerant to oil. Oil efficacy was compared to an organophos phate pesticide and an insect growth regulator, and all provided simil arly effective control of psylla nymphs. Control of eggs was not achie ved by any of the treatments as application of sprays was not correctl y timed.