Dinámica poblacional de la psila (Cacopsylla pyri L.) y de sus enemigos naturales en plantaciones comerciales de peral de Girona

VILAJELIU, M.; VILARDELL, P. y LLORET, P., 1998: Dinamica poblacional de la psila (Cacopsilla pyri L.) y de sus enemigos naturales en plantaciones comerciales de peral de Girona. Bol. San. Veg. Plagas, 24(2): 231-238. Arthropod often commercial pear orchards of Girona area (Spain) were assessed by the beating branches method throughout the 1992-94 period, to know the most important factors that determine the dynamic populations both of the pear psylla (Cacopsylla piri L.) and their natural ennemies. Populations of pear psylla resulted to be heterogeneous among orchards and years, and anthocoridae and miridae, like crysopidae and arachnidae, had proportional much lower values than pear psylla adult captures. The highest populations of pear psylla were reached in June and particularly in October and the lowest during winter months. Antocoridae and miridae showed the highest populations in June and arachnidae and crisopidae in autumn but all predators appeared not enough to achieve biological control of the pear psylla. Data of the dynamics and possible causes of the observed behavior are discussed.