5 - 



especially with 'Stayman', ' Rome ' , ' Winesap ' , and 'Jonathan' culti- 

 vars. Non-bearing 'Red Prince Delicious' planted at our Research 

 Center in 1971 or 1972 have developed leaning. The leaning appears 

 to be caused by something other than poor anchorage . In other orch- 

 ards, poor anchorage appears to be a problem. Trees that were pro- 

 vided either no support or a short stake for support at planting, 

 now require an 8-foot stake for support in some instances. This 

 was not due to early, heavy cropping. Whether or not the stakes can 

 be temporary or needed permanently is not known. 



We need a free-standing tree smaller than that produced by M.7. 

 But I'm beginning to wonder if M.26 is the answer for some orchards. 

 Approximately 8% of the trees in Massachusetts on size-control root- 

 stocks are on M.26. Thus, in several years we can better evaluate 



M.26. 



*************** 



MITE PREDATOR STUDIES IN 

 MASSACHUSETTS APPLE ORCHARDS IN 1976 



Robert G. Hislop and Ronald J. Prokopy 

 Department of Entomology 



In several 1976 issues of Fruit Notes , we described certain 

 techniques developed by researchers in other apple growing regions 

 of North America to reduce spraying for apple insects and mites 

 without sacrificing fruit quality or quantity. These accomplish- 

 ments were made possible by careful monitoring of insect popula- 

 tions in the orchard, and selection of orchard sprays to which mite 

 predators were resistant. In this issue of Fruit Notes , we will 

 describe work we have been doing this past year toward a similar 

 goal of reduced spraying for mites in Massachusetts apple orchards. 



Our study is long term and its objectives twofold: (1) to 

 determine which species of mite predators occur naturally on wild 

 or unsprayed abandoned apple trees, and (2) to determine if any of 

 these predators occur or thrive in commercial orchards. This should 

 provide some indication as to which types of spray programs are con- 

 ducive to the buildup of these beneficial predators in our orchards. 



We knew at the beginning of our study that Amblyseius fallacis , 

 a predatory mite known to play a key role in the suppression of red 

 and two spotted spider mites in some commercial apple orchards in 

 the midwest and southeast, also occurs in some northeastern states. 

 Several of its habits are well known, such as remaining in the 

 ground cover until July, when it moves up into the tree canopy to 

 feed on plant feeding mites. Here it is exposed to the constant 

 onslaught of cover sprays directed against principal insect pests. 



