Thursday, June 20, 2002

Pinching shoots is a young tree training technique used on mostly first-, and second -leaf apple trees to promote fruiting and manage growth in the top of the trees of vertical axis, slender-spindle, or super-spindle orchards. Rapidly growing shoots that are six to eight inches long, that are in the top one-fourth of the tree, and that originate from the leader, are candidates for pinching. Pinch-back the shoot two inches using your thumb and finger(s) or pruners. (See picture.) Pinching will do two things: weaken the growth of the developing shoot so it is not as likely to compete with the leader; and promote the development of a fruit bud in the vicinity of the pinch if done now into early July. This technique will also prevent the tree from becoming top heavy, which of course would eventually mandate a less desirable dormant pruning cut be made. To view a short web video of the pinching technique, go to 'Techniques for Training Young Apple Trees on the UMass Fruit Advisor. 4:04:38 PM

Powdery mildew -- as seen on this young Cortland apple tree -- has not been too hard to find in the Northeast this year. Generally, a good fungicide program aimed at apple scab keeps mildew at bay, however, in young trees and/or where fungicide coverage has lapsed, mildew may be a problem. Severe infection can kill the terminal foliage and shoots, and result in winter injury and stunted tree growth. Mildew thrives when temperatures are in the 60-8 F. range, particularly with high humidity. Unlike scab, rain is not a pre-requisite for infection to occur. Certain varieties are more susceptible to mildew, including Cortland, GingerGold, Jonathan, and Granny Smith. Unfortunately, once and infection has been established, there is not much that can be done about it -- except remember to maintain a good fungicide program during scab season (particularly on young, non-bearing trees) next year! 3:36:32 PM