The pear psylla in Oregon

Published November 1972. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalogSince its discovery in Oregon in 1946, the pear psylla, Psylla pyricola\ud Forster, has become the most serious insect pest of pear. Damage to pear\ud trees include the transmission of pear decline disease which has caused losses\ud of trees, injection of a phytotoxic toxin resulting in tree shock and injury,\ud and secretion of honeydew causing fruit marking. Aspects of pear psylla\ud biology are discussed in relation to the pest's control. Natural enemies are\ud known to exert some suppression of pear psylla populations late in the growing\ud season but the application of insecticides, many of which the pest has\ud become resistant to, is the only means presently available for reducing pear\ud psylla populations to subeconomic levels