Since our plots were small, and we only used the one insecticide product, it is difficult to determine exactly why protection wasn't as good as we had expected. The bottom line for growers, at this point at least, is that it is likely there are critters, specifically stink bug and Japanese beetle, out in your peaches that can cause extensive damage late in the growing season. Be aware by monitoring. And keep protected with an insecticide if you have a history of problems. Several blocks which received oil treatments alone are showing significant infestation, up to 15 or more adults per terminal and heavy egglaying.
Most eggs have yet to hatch, and it is too early for treatment against the summer generation.
When sampling for pear psylla, it is also a good time to look for buildup of two-spotted mites on pear. At this growth stage last year, TSM were seen in moderate numbers moving into canopies, likely pushed into the canopies by mowing of the understory. If mites become a problem on pears, they can be controlled by use of Vendex, Carzol, Kelthane or Pyramite. Pyramite is also labeled for use against pear psylla, but early data suggest that the cost of the high rate needed to gain control of psylla may be outweigh the efficacy. It will let you check on things like the potential for curculio damage, or the best way to treat for flyspeck given the weather.