Every August, I spray my pecan grove during the first week of August to reduce stink bug populations. I know stink bugs are active in the grove when I start seeing dropped nuts on the orchard floor. If you look over the outside of a dropped nut, you'll have a hard time finding any puncture marks. However, cut open the dropped nut and you'll find that the inside of the nut has turned dark brown or black (photo at right).
The unusually wet summer we've had this year has made pecan pest control even trickier. Heavy rainfall starting on the first day of August and again a week later has saturated the soil allowing pecan weevils to start emerging. Under moist soil conditions throughout the month of August, weevils will not flush out all at one time. Instead they will emerge slowly over the entire month. So this year, my early August stink bug spray is also aimed at controlling any early emerging weevils.
The hot, humid weather we've had all summer long has also made conditions perfect for the spread of pecan diseases. Although pecan scab is our primary disease problem, wet conditions late into the summer means that pecan anthracnose and downy spot will also become problematic. To keep all these diseases in check this summer, I made my forth fungicide application with my early August spray.
Determining the best day to spray was also a problem. It didn't look like I could afford to let things dry out completely so I just had to pick a day with the lowest rain chances and pray I would get at least 8 hours of drying time to allow the pesticides to do their job. I like to start spraying at first light. The winds are calm and the high relative humidity allows the spray to drift up through the entire tree canopy allowing me to get excellent spray coverage.
In two weeks, I'll be spraying the grove again. This time with an insecticide specifically aimed at pecan weevil.