Control tests against the citrus mealybug on Citrus.
In tests on grapefruit in the Spanish Province of Castellon, spot treatments were made on 27th May 1971 to control the first foci of infestation by the citrus mealybug [Planococcus citri (Risso)] on the trunks and main branches of the trees. Examination two and seven days after treatment showed that complete control had been afforded in each case. The products tested contained 50% fenitrothion, a mixture of 50% fenitrothion and 40% dimethoate, 50% omethoate, 40% methidathion, 40% dimethoate or 50% dichlorvos. All except the last were used at 100 cm3/2 litres water, to which 1 litre white summer oil was added; dichlorvos was used at 150 cm3. A brush was used to wet the foci, and each tree received about 0.66 litre of liquid. Although the results were excellent and this method of treatment has advantages, the cost was excessive and further tests will be made to ascertain whether lower application rates could be as effective.zIn spray tests carried out in early September on orange to control large populations of the Coocid that had developed during the summer, the materials that gave the best initial control and retained their effectiveness for 15-30 days were sprays containing 0.0625% omethoate, 0.04% methidathion, a mixture of 0.075% fenitrothion and 0.06% dimethoate, or a mixture of 0.04% dimethoate, 0.08% malathion and 0.012% tetradifon.y