Establishment and Biocontrol Potential 

 of Released Typhlodromus pyri 

 Predator Mites in Massachusetts 

 Apple Orchards: 2000-2003 



Ronald Prokopy, Starker Wright, Isabel Jacome, and William Coll 

 Department of Entomology, University of Massachusetts 



Jan Nyrop, Karen Wentworth, and Carol Hering 



Department of Entomology, Cornell University, NYSAES, Geneva, New York 



In the 2000 issue of Fruit Notes, we reported the 

 results of a 3-year project (1997-1999) aimed at 

 establishing the predator mite Typhlodromus pyri in 

 Massachusetts apple orchard blocks of different tree 

 sizes. Results showed that following release in 1997, 

 T. pyri became established in all eight blocks by the 

 following year, spreading fastest from tree to tree 

 among cultivars on M.9 rootstock and slowest from 

 tree to tree among cultivars on M.7 rootstock. Result 

 also showed that even in blocks on M.7 rootstock, by 

 1999 T. pyri had spread to the most distant trees in the 

 49-tree blocks and provided effective block-wide 

 suppression of European red mites. 



Encouraged by results of this 1997-1999 project, 

 in 2000 we launched a 4-year study to further 

 characterize the establishment and spread of released 

 T. pyri in commercial apple orchards in Massachusetts. 

 We asked five questions. First, would the addition of 

 pollen to trees in which T. pyri were released enhance 

 the buildup of T. pyri'? This predator is known to feed 

 on pollen when prey mites are low in abundance and 

 previous research has shown that supplementary pollen 

 could elevate predator numbers. Second, in which 

 direction is T. pyri likely to spread fastest following 

 release from trees on row 4 of a block: toward row 1 

 (the perimeter) or toward row 7 (the interior)? Third, 

 would the establishment of American hazel trees 

 opposite plots in which T. pyri were released contribute 

 to the buildup of T. pyri and/or Amblyseius fallacis as 



predator mites? American hazel trees have been found 

 b\ others to harbor substantial populations of predaiory 

 mites. Fourth, what is the relationship between the 

 abundance of T. pyri and the abundance of Amblyseius 

 fallacis as predatory mites? Fifth, w ould the release of 

 T. pyri in 2000 guarantee effectne biocontrol of 

 European red mites in subsequent years? Here, we 

 present data that address each of these questions. 



Materials & Methods 



Our experiment was conducted in 12 blocks of 

 apple trees in ten commercial orchards. Each block was 

 about 140 meters long by seven rows deep and was 

 di\ ided into four equal-size plots. The perimeter row 

 of each block was bordered by woods, hedgerow or 

 open field. Trees were on M.9, M.26. or M.7 rootsiock 

 and were principally Mc Intosh. Cortland, Gala, 

 Empire, Jonagold or Fuji. 



There were four treatments at the outset in May of 

 2000 (one per plot): (1)7^ pyri released in the presence 

 of fresh cattail pollen, which was applied to the tree 

 canopy by a commercial pollen applicator (E-Z Power 

 Duster, Firman Pollen Co, Yakima. WA) at the rate of 

 one-seventh ounce of pollen (about 100,000 pollen 

 grains) per tree, (2) T. pyri released in the absence of 

 pollen amendment; (3) no release of T. pyri but, as with 

 the first and second treatments, no insecticide applied 

 after mid-June (apple maggot flies were controlled by 



Fruit Notes, Volume 68, Spring, Summer, & Fall, 2003 



