Temperature monitoring sites for tree fruit pest management in North Central Washington

Abstract

Tree fruit production sites in the Wenatchee River valley and surrounding area are topographically heterogeneous. The differences in the accumulation of day-degrees at 31 sites (1979) and 36 sites (1980) suggested 14 temperature monitoring sites might be required to provide accurate resolution of arthropod pest development. However, examination of the clustering patterns of sites revealed that 11 sites would provide the resolution necessary to determine pest development. Sites near the same location in the Wenatchee River valley did not accumulate day-degrees at the same rate. Sites north of the river with south aspect were much warmer than their equivalent sites on the south side. A multiple regression model using site parameters of elevation, slope aspect and slope degree did not provide an adequate explanation of the variability between sites.