Pest Status of Insects and Mites on Pear in Southern Oregon2

The economic status of 7 pear pests in southern Oregon was evaluated over an 8-year period, 1964-71. Comparisons of pest levels and economic losses were made in treated and untreated situations. Of the 7 pests which are targets for spray applications, the twospotted spider mite, Tetranychus urticae Koch; the European red mite, Panonychus ulmi (Koch); the yellow spider mite, Eotetranychus carpini borealis (Ewing); and the pear psylla, Psylla pyricola Foerster, apparently have been promoted to pest status through use of spray chemicals. Despite the undesirable side effects resulting from use of pesticides, the added material and labor costs are compensated for by a minimum ratio of 5:1 by the increased value of fruit received by control of the codling moth, Laspeyresia pomonella (L.): the pear rust mite, Epitrimerus pyri (Nalepa): and the San Jose scale, Quadraspidiotus perniciosus (Comstock). The grower benefits also by obtaining control of nontarget phytophagous species.