-7- 



Early, heavy bearing is causing weak growth in some instances 

 Reduction o£ crop load by hand thinning rather than by chemical 

 thinning appears to be the best solution to this problem because 

 tree vigor varies considerably within a block. At present, we 

 have not seen or heard o£ any problems with fire blight associated 

 with M.26. 



Figure 1 to the left shows 

 a six-year-old Macspur on M,26 

 The trees in this block are 

 planted 14 feet x 18 feet. It 

 is obvious that on this site 

 the planting distance is too 

 wide and that the trees have 

 low vigor. 



In 1976 we planted a block of Rogers Mcintosh and Gardner Deli- 

 cious (a standard- type strain) on MM. 106, M.7, and M.26 in heavy 

 soil. The trees on M.26 are very vigorous in comparison to most 

 blocks in Massachusetts on this rootstock. Mcintosh but not Delicious 

 were significantly smaller in 1978 on M.26 in comparison to those on 

 M.M.106 and M.7 rootstocks (Table 1). Mcintosh produced about 0.1 

 of a bushel per tree in 1978 regardless of rootstock. The Delicious 

 had a light bloom but produced no fruit. 



Growers establishing plantings on M.26 will have to be more 

 selective of soils than in the past. Shallow soils, with hardpans 

 that prevent deep rooting, are producing trees that look like "free- 

 standing M.9's" and the trees are subject to frost heaving. Trees 



