These experiments illustrate that scoring is an effective method for 

 controlling growth in vigorous trees. It not only controlled growth but 

 also increased flowering and cropping on heavily-pruned trees, thus con- 

 verting unproductive vegetative growth into fruitful wood during the time 

 the trees were being maintained in their allotted space. Scoring is a tech- 

 nique that you should consider if it was necessary to prune certain blocks 

 this past winter more heavily than they should have been pruned. 



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POMOLOGICAL PARAGRAPHS 



Wi I I iam J . Lord 



Department of Plant and Soil Sciences 



University of Massachusetts 



Chemical Control of Vetch . Paraquat pi us simazine is the most commonly 

 used herbicide combination in Massachusetts. One of the "escape" weeds from 

 continuous use of this combination is common vetch, an alternate host of 

 plant bug, a very troublesome insect under our conditions. Studies in 

 Ontario indicate that terbacil rather than simazine would be the better 

 choice in orchards where common vetch is a problem. 



Determining the need to thin . Probably the most dependable means of 

 determining the need for chemical thinning of Mcintosh 10 to 1^ days after 

 bloom is by calculating the number of fruits set per TOO blossoming clusters 

 by actual count on several trees. This means that the number of blossom 

 clusters on at least 2 limbs of 5 to 6 trees must be counted and recorded in 

 each block. The number of fruits developing on the same limbs must be 

 determined 10 to 1^ days after petal fall. If one finds (by dividing the 

 number of apples by the number of blossom clusters) an average set in excess 

 of 50 to 60 fruits per 100 blossoming clusters on trees that have a reason- 

 ably heavy bloom, some thinning of Mcintosh may be necessary. A final set 

 of 25 to 35 fruits per 100 blossoming clusters seems to be about right for 

 heavy to moderate blooming Mcintosh. If 50 or less fruits are left 10 to ^^ 

 days after petal fall, one may expect reductions in set during the June drop 

 period to be sufficient so that chemical thinning will not be necessary. 

 When in doubt, omit the spray or use NAAm at 25 ppm or carbaryl . We have 

 never seen these materials seriously overthin Mcintosh. 



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