Figure 1 In July and August of 1998, abundance of T. pyri mite predators on leaves sampled from third- 

 level IPM blocks (in wtiich T. pyri were released on the center tree In mid-IVlay 1997) and first-level IPM 

 blocks (in which no releases of T. pyri were made). 



Third-Level IPM Blocks. Low Tree Density 



Sample Dale 



Legend: 



First-Level IPM Blocks. Low Tree Density 



Sample Date 



First-Level IPM Blocks. High Tree Density 



Sample Date 



Center Tree 



Center Row, Outer Trees 



Outer Row, Center Trees 



based pest management practices, but it embraces manner described in the Fall 1997 issue of ¥ruit 



integration with horticultural concerns (such as tree Notes. No T. pyri were released in first-level IPM 



size) as an added component. blocks. Three times during the summer of 1997 



T. pyri were released onto the center tree of and four times during the summer of 1998 in each 



each third-level IPM block in May of 1997, in the of the 48 blocks, we sampled 25 leaves from the 



Fruit Notes, Volume 64 (Number 1), Winter, 1999 



11 



