The effects of plant cover on population of pear psylla {Cacopsylla pyricola)and its predators

摘要

Cacopsylla pyricola (Forster, 1848) (Hemiptera: Psyllidae) is a serious pest of pear in all pear growing areas. In the scope of an integrated pest management, a two consecutive years study was carried out to determine the effects of plant cover on pear psyllid population and its predators. Two treatments including plant cover and bare ground were applied in a randomized complete block design with three replicates. The sampling of the pest and its predators were done weekly by beating technique and leaf sampling. The data were subjected to analysis of variance (ANOVA). The results showed that plant cover had significant effect on the increase of predators on the trees (P < 0.001). The psyllid specialist predator, Anthocoris nemoralis (Fabricius, 1794), had the highest population among the pear psyllid predators (0.29 per sample). Plant cover had no significant effect on reducing the population of eggs, nymphs and adults of the pear psyllid. Despite the increase in the population of predators led byplant cover, lack of their effectiveness to reduce the pear psyllid population is discussed.