MONITORING OF POPULATION DYNAMICS OF Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) DURING TWO SEASONS IN A POMEGRANATE (Punica granatum L.) ORCHARD IN CENTRAL CHILE

Abstract

Pseudococcus viburni is the main pomegranate pest in Chile, so an efficient monitoring system is required. Four monitoring methods were evaluated between 2011 and 2013 in a pomegranate orchard in the Metropolitan Region, Chile. The methods evaluated were: cardboards on trunks, double-sided tapes on branches, fruit sampling and foliage sampling. Cardboards placed on the trunk at 120 cm from the ground were the most efficient method, showing pseudococcid migration from overwintering sites to the foliage since the spring (September). Three annual generations (spring, summer, and autumn) were observed for P. viburni in cardboards, but low populations were found during the winter. There was an increasing number of nymphs and adult females under cardboards during April-May (harvest time), attributable to the emigration from naturally splitting fruits. An increasing fruit calycinal cavity infestation was observed from fruit set to harvest, reaching above 75% of sampled fruits even though an insecticide spray program was in place. Foliage sampling and
double-sided tapes were not efficient for P. viburni monitoring. Fruit infestation was not linearly correlated either with fruit parameters (size or weight) or pseudococcid densities in cardboards, but it was correlated with the percentage of infested cardboards. Climatic variables did not exhibit any significant correlation with pseudococcid densities. These results will help improve the agrochemical spray timing against P. viburni in pomegranates.