I was seeing water split on Pawnee over the weekend, which is a sign they will soon be at shell hardening. I suspect that will occur possibly by the end of next week. This means we are looking at probably one more fungicide spray on Pawnee to get them through. Most other varieties will need at least 2 more. If you are in a highly scab prone area with a highly susceptible variety you may need 3 more if current weather persists.
I have heard of some growers considering fruit thinning their trees by mechanical shaking. If so, bear in mind that fruit thinning for improving return crop is a highly time sensitive procedure. When you slice the nut longitudinally, you can evaluate the crop maturity stage, looking for the development of the cavity that will eventually fill to become the kernel. When the tips of the U-shaped cavity are half way to the end of the nut, you can begin thinning and when they reach the ends of the nut, you can continue to thin and improve size and quality but probably will not help return crop beyond that point. Also, bark can be easily damaged by shaking at this time due to the tree moving water. Turn off irrigation for several days and wait for a dry window in the rainfall to fruit thin and avoid bark damage.
Pawnee are at the thinning stage right now. I would say you probably have through the end of this week to get that done. Varieties like Lakota should likely be thinned from now through the end of next week, and most other varieties would fall into the first or second week of August depending on expected maturity date.
Another time sensitive task for pecans at the moment is leaf sampling. The leaf sampling period runs through August 7 becasue the July 7-August7 period is when nutrients are most stable in the leaf. This is the only way to know the fertility status of your trees and along with a soil sample, be able to plan your fertilizer program for next year. Therefore, do not forget this important task.
Black aphids have been ramping up over the past week and a lot of growers with black pahid-susceptible varieties have been spraying for them. Bear in mind that it is imperative to rotate your aphicide chemistries. We have a number of good aphid products out there, including Transform, Carbine, Sefina, Fulfill, PQZ, and Sivanto. Rotate these products as needed for control. If you have been using one repeatedly in years past I recommend rotating to another one. The fastest way to lose a chemistry is to use it over and over. We still have at least another month of battling aphids to get through so rotate your chemistries and let’s preserve these tools for as long as we can. Later in the season when mites really get fired up, Nexter is not a bad choice to take out both aphids and mites.
The frequent rains have been playing havoc with keeping trees sprayed recently. Five to six hours of drying time would be nice but I know that may not always happen. If you are caught by rain, go back and re-spray anything not dried on for at least an hour and then plan on tightening up the spray interval for the next spray.
On that note, here’s a visual reminder of why its a good idea to start planting resistant varieties. Both of these photos were taken today from trees that have had 0 fungicide sprays and are located about 600 yards apart .
‘Wichita’ with 0 fungicide sprays at UGA Ponder Research Orchard
‘Lakota’ with 0 fungicide sprays at UGA Ponder Research Farm
