BIOLOGY  AND CONTROL OF THE MEALYBUG Planococcus citri (Homoptera: Pseudococcidae) IN CITRUS GROVES
       
       ABSTRACT
       
       Planococcus citri is considered an important citrus pest all over the world. The management of this phytophagous is based on Integrated Production principles, requiring accurate knowledge about biology, seasonal cycle and behaviour of P. citri population. Between 1992 and 1998 P. citri and its natural enemies population were investigated on several citrus groves, treated or not with pesticides. These studies were carried out both in different parts of the tree and using sticky traps with sexual pheromone.
       
       In the studied area, P. citri developed five generations in a year.  Developmental threshold and thermal constant were 8,3ºC and 562,4 degree-days. First instars invaded the calyxes of the fruits from May to July, reaching on July high levels, averaging 72% percentage of invaded calyxes. P. citri invaded the fruits from the calyxes from August, averaging 22% of external occupied fruits, for all the groves and years. P. citri population fluctuated from year to year, between 10% and 30% occupied fruits. Organophosphates applied in spring satisfactorily controlled P. citri population. We have determined that the economic thresholds are, in spring 70% of invaded calyxes, and on August and September, 20% of externally invaded fruits. 
       
       P. citri population showed an aggregative distribution under the calyx of the fruit, on the fruit and on the trunk, with a b Taylor’s index of 1,45, 1,41 and 1,42, respectively. We recommend sampling 130 fruits with enumerative sampling method when population is low or medium. Just in case of high population we recommend to sample 200 fruits, with a binomial sampling method.
       
       Biological control exerted an important role in the regulation of P. citri population. The usual species found were the Himenoptera Encyrtidae Anagyrus pseudococci and Leptomastidea abnormis, and the Coleoptera Coccinellidae Cryptolaemus montrouzieri. They showed seasonal variations of their abundance and activity, depending on climate factors or pesticide treatments.