EFFECTS OF POST-HARVEST APPLICATIONS OF BUPROFEZIN, PYRIPROXYFEN AND MINERAL OIL AGAINST SAN JOSE SCALE (Diaspidiotus perniciosus Comstock) ON APPLE TREES

Abstract

Diaspidiotus perniciosus is a major pest of pome and stone fruits that can be controlled using post-harvest applications. The objective of this study was to determine the effect of pyriproxyfen and buprofezin on crawlers (insects in their juvenile stage growth) of D. perniciosus (black-cap and grey-cap) on apples var. Royal Gala. The experiment was conducted in the fall of 2012. Insecticides were applied alone and in mixture with mineral oil at 2% and a control treatment applied only with water. Applications were made with a handgun at 250 PSI and 3500 L ha-1 over infested apple trees. Crawlers on twigs were evaluated in the laboratory using a stereoscopic magnifier 48 days after application (DAA). The results were expressed in mortality percentage. A completely randomized experimental design was used with 6 treatments and 4 replications. The experimental unit consisted of 2 adjacent trees; a sample of 30 twigs was collected from the trees to determine the mortality over 1000 specimens per replication. It was concluded that, when applied alone, pyriproxyfen at 0.06% and buprofezin at 0.1% can partially control crawlers of D. perniciosus in fall. It was also found that buprofezin at 0.1% in mixture with mineral oil 1.5% can effectively control San Jose scale crawlers on apple trees, with similar effects to those observed with mineral oil at 2.0%. In addition, the mixture of pyriproxyfen and mineral oil at 1.5% controls crawlers better than the treatment with mineral oil at 2.0%.