Pecans are still the nut sizing period and will likely be through mid-August. Aphids have been strong with dry weather, and sprays have also led to increase in mite populations. Our late season aphid generations have a lower threshold we need to watch for. Here is an update from UGA Extension Pecan Specialist Dr. Lenny Wells:
“Black aphids can be one of the most difficult pecan pests to manage because they often slip in, do their damage, and are gone before you know they are there. For this reason, they require pretty intensive scouting on susceptible varieties like Schley, Sumner, Oconee, and Gloria Grande. Anyone growing these varieties probably needs to check for black aphids at least twice a week from July through August. There is normally a flight of black aphids that comes through sometime in early June. These are usually winged adults that come through to feed, damage a few leaves and condition the foliage for the later generations (black aphids reproduce more and develop more rapidly on damaged foliage).
The late season generations, seen now, can develop into a problem quickly. These cause the characteristic yellow spotting, developing necrosis, and eventual loss of leaves. Tolerance for black aphids at this time of year should be very low because August is a critical month for both the current season’s crop and the crop potential for next year. Thus, trees should be kept as stress free as possible at this time. For this reason, it is recommended that pecan trees are sprayed when only 15% of the terminals sampled have more than one black aphid adult with nymphs present on a compound leaf.”