We are at a critical time in the season for pecan production in terms of both this year’s quality and next year’s flower production.. A lot happens within a pecan tree in August. The shells are hardening and the nuts are moving into the gel stage to soon begin filling with kernel. At the cellular level, the tree is determining whether to make vegetative or reproductive shoots for the following year. With so much going on in the tree at this time, it is critical to keep them stress free through this month and the first two weeks of September.
A big part of this will be irrigation. Irrigation systems should be run at full capacity from mid August through mid September. The crop seems to me to be just a bit early this year so move up to 3600-4000 gal/acre/day about the middle of next week. Turn systems off for 3 days if you get a 2″ rain or more.
We should be nearing the end of fungicide sprays for the season. Once the shells harden any scab that gets on the nuts at that point is largely cosmetic. Many varieties like Stuart, Schley, Sumner, Oconee, Cape Fear, Creek, etc. should require only 1 more spray if they are relatively clean at this point. Susceptible varieties like Desirable and Caddo may require an additional spray beyond that, certainly if they already have a bit of scab present. Pawnee should be about done since harvest of this variety will be starting in about a month and a half.
Keeping the trees stress free right now will involve management of aphids and mites. Do all that you can to keep these pests down for the next month or so.
Dr. Will Hudson provides the following suggstions:
“Growers across the state are seeing an increase in black aphids. For growers with old Schley trees this has been going on for a while, but the other susceptible varieties like Sumner and Gloria Grande are experiencing a build-up now. Remember, if you see nymph clusters you need to take steps to protect your foliage and avoid the kind of damage that can affect your crop next year. Imidacloprid still controls black aphids pretty well, but requires the higher rate on the label (several formulations are available; the 2 lb materials need 5.6 oz/acre). Other neonicotinyls like Belay and Assail are also effective. If you also have yellow aphids then Carbine, or Fulfill would control both. Closer is one of the most effective options at the moment.
We are also seeing some mite flare-ups in scattered orchards. Mites can be controlled with abamectin products (Agri-Mek, Abba Plus, etc.), Portal, Acramite, or Nexter. The Nexter will get both aphids and mites, and may be a good choice where those pests are present and a weevil spray is needed or likely. Check labels for rates and surfactant requirements.
Dodging showers can be a challenge if you need to treat lots of acres with few sprayers, and sometimes the rain catches you or pops up right after application. If it starts to rain while you are spraying, stop the sprayer. It will do little good to apply an insecticide (or fungicide) that will be washed off immediately. If the rain comes after you finish, you may be okay if the spray has dried on the leaves. A good rule of thumb is that if you get a rain within 1 hour or less of spraying and you will need to retreat.”