June. T. pyri is known to be highly adversely 

 affected by synthetic pyrethroid insecticide and 

 also adversely affected by EBDC fungicide 

 (when applied from bloom onward) but not by 

 captan or benomyl. Each block was comprised 

 of 49 trees (7 rows x 7 trees per row) and of the 

 cultivars Mcintosh, Empire, and Cortland. 

 Third-level IPM is similar to second-level IPM 

 in focus on using biologically-based pest 

 management practices, but it embraces 

 integration with horticultural concerns (such 

 as tree size) as an added component. 



In May, blossom clusters harboring T. pyri 

 were picked from an orchard at the New York 

 State Agricultural Experiment Station at 

 Geneva, sent by overnight mail to 

 Massachusetts, and within three days were 

 distributed to orchard blocks. Each third-level 

 IPM block recieved 100 clusters, which were 

 attached to twigs on the center tree of the block 

 using twist ties. No T. pyri were released in 

 first-level IPM blocks. Every 3 weeks from late 

 July through early September in each of the 48 

 blocks, we sampled 25 leaves from the center 

 tree, 15 leaves from each of the two outermost 

 trees in the center row, and 15 leaves each from 

 the center tree in each of the two outermost 

 rows. The leaves were sent by overnight mail to 

 Geneva, New York for the identification and 

 counting of pest and predatory mites. In all, 

 about 2,600 leaves were sampled for each of the 

 three sampling periods. 



Results 



As shown in Table 1, significantly more T. 

 pyri-were present on the center (release) tree on 

 each sampling date in blocks of each tree size 

 than on outer trees in center rows of blocks 

 (that is, the fourth tree up row and the fourth 

 tree down row from the center tree in a block) or 

 on center trees in outer rows of blocks (that is, 

 the fourth tree directly across row to either side 

 of the center tree of a block). In fact, extremely 

 few or no T. pyri were found on any tree except 

 those on which they were released. In contrast, 

 there were no significant differences among 

 tree locations within plots in numbers of A. 

 fallacis sampled on each sampling date in 



blocks of each tree size (data not shown). The 

 same was true for European red mites (data not 

 shown). 



The finding that, on average, numbers of 

 European red mites were not significantly 

 fewer on release trees than on non-release trees 

 on any sampling date in blocks of any tree size 

 suggests that T. pyri were not able to build to 

 sufficient numbers to provide biocontrol of 

 European red mites during the three months 

 following release. This was not a surprising 

 result because T. pyri populations grow slowly 

 and usually are not capable of rapidly 

 controlling moderate to high density red mite 

 populations. Even so, there was one block of 

 small trees in which T. pyri were released 

 where every tree (save one) in that block (as 

 well as every tree in each of the other five study 

 blocks in that orchard) was heavily bronzed as 

 a consequence of mite injury. The only tree that 

 was not bronzed was the center tree on which T. 

 pyri were released. 



Data in Table 2 summarize information of 

 all leaves sampled in a block and compare 

 average numbers of T. pyri, A. fallacis and 

 European red mites per leaf between first-level 

 IPM blocks and third-level IPM blocks and 

 among small, medium, and large trees within 

 each sampling date. For each sampling date, 

 there was no significant difference among 

 blocks of small, medium-sized, and large trees 

 in numbers of 7! pyri found in third-level IPM 

 blocks. In every case, third-level IPM blocks 

 had significantly more T. pyri than first-level 

 IPM blocks. For A. fallacis there were no 

 significant differences in numbers found 

 between first-level and third-level IPM blocks 

 or among tree sizes for any sampling date. The 

 same was true for European red mites. 



Information on type and amount of 

 insecticide, acaricide, and fungicide used 

 before bloom, from bloom through mid-June, 

 and after mid- June is given in Table 3. Blocks 

 of small, medium, and large trees in the same 

 orchard were treated in the same manner. 

 With respect to insecticide, some Asana was 

 used before bloom and some Lorsban after mid- 

 June in first-level blocks. Both of these 

 materials are known to be detrimental to T. 



10 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



