Abstract: Studies on chemical control of the pine armoured scale seriously infests pine trees were conducted during 1988 and 1989 in Guangdong Province. Through a series of screening tests for effectiveness of 16 synthetic insecticides in tile laboratory, field trials and experiments by aerial spray applications of promising materials (including various formulations of oil emul sions) in the forest, we succeeded in estatblishing the outstandingly high effectiveness of an oil emulsion, a product which we formulated by mixing the rubber tree seed oil (or chinaberry seed oil) with the diesel oil at a ratio of 3:7 with an emulsifier in an appropriate amount. Results of field trials by ground spray application of the test materials showed that at con centration of 5%, the product gave a high control of the scale insect up to 90-100%. In two experiments using aerial spray application of the materials it was shown that this mixture when diluted with water at 1:4 equivalent to 75 kg/ha gave a control efficiency above 70%, which means much more potent than the conventional pine resin-diesel oil mixture commonly used inHui-Ding County, Guangdong Province and other places. Meanwhile, this produc' was found to be safe to Encarsia sp. And Alphytis sp., hymenopterous parasites as the most important naturalenemies of the pine armoured scale and proved to have no harmful effect on the environment. Furthermore, the formulation can be easily pre pared as an emulsion. It is suggested that the product could be widely used for the effective control of the pine armoured scale and other insects infesting the pine trees.

Key words: Hemiberlesia pitysophila Takagi——plant oil——mineral oil——spraying by airplane