Phenology and management of the white mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae), in Southern Spain

Abstract

White mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae), is one of the most damaging pests of mango crops around the world, causing conspicuous pink blemishes on ripe fruits that reduce their commercial value. This research aims to determine the seasonal trend of this invasive pest in Southern Spain as a first step to develop an integrated pest management program. Periodic sampling in two mango groves from June 2013 to December 2015 showed that A. tubercularis completed four overlapping generations annually. Pest density started to increase in spring (mid-May), reaching the highest pest population levels in summer (mid-August) and early autumn (mid-October), corresponding with the ripening and harvesting periods, respectively. Aulacaspis tubercularis was mostly found on the upper leaf surface, although the pest was also located on the lower leaf surface. Fruit became infested by crawlers of the first generation during the early fruit development period and the scale was more abundant during the ripening period. In addition, the efficacies of four reduced-risk insecticides were tested at commercially recommended field rates on nymphs and adults of A. tubercularis in mango trees. Fourteen days after the treatment, paraffin oil at 1.25% was the most effective insecticide (90.87%) for both scale stages, followed by diatomaceous earth (77.18%), azadirachtin (69.32%) and paraffin oil at 0.75% (46.24%). These results will improve field sampling protocols and facilitate the development of integrated pest management programs based on the conservation of natural enemies combined with paraffin oil applications in spring before the scales migrate to the fruit.