UMass Healthy Fruit Volume 7, No. There are several factors that should be considered when deciding to use a petal fall thinning spray.
Bloom is heavy in most areas of the state, due in large part to the light crop last year.
There was little or no cold damage from low temperature this winter and early spring. Temperatures have been moderate for the past few weeks, assuring complete and full development of flowers parts. Flowers and spur leaves appear to be very healthy. Weather, in general, has been favorable for good bee activity and pollination. While memories of a light crop last year may cause you to adopt a conservative thinning strategy, this may not be appropriate, since all of the above factors favor a heavy initial set.