PARASITAT1ON RATE OF THE LARVAE OF PEAR PSYLLA (Cacopsylla piri (L.)J IN ORCHARDS WITH DIFFERING INTENSITY OF CHEMICAL CONTROL

摘要

During the last five years a growing number of pear psylla has been observed in Poland. Inspections carried out since 1993 in pear orchards have shown that the dominant species is Cacopsylla piri. Much less commonly observed were Cacopsylla pirisitgaand only single specimens of Cacopsylla piricola were found. There are problems with efficient chemical control of pear sucker in some orchards. In Poland (partlculaly when synthetic pyrethroids and organophosphate isecticides are used), as in many othercountries. At the same time, in other orchards despite constant occurence of these pests, their incidence remains on low or medium level. The main role in reducing the number of pear psylla is attributed to predators, however parasitoids are also important (Armand et al., 1992; Me Mullen, 1966). The aim of the observations was to recognize the parasitation rate of pear psylla in Polish pear orchards and to study the composition of their species.