After fighting through some mechanical problems with our tractor and sprayer, we finally sprayed the pecan grove to control stinkbugs and shuckworm today (photo at right). We had planned to spray earlier in the week in response to the nut drop we have been seeing but we ended up having to wait for parts to arrive.
We applied Warrior II at the rate of 2.56 oz/ac. But, "How much do I put in the tank?" you might ask. Many growers are frustrated by fact that suggested rates on pesticide labels are given as amount of product to apply per acre rather than amount to mix in 100 gallons of water. Pesticide manufacturers are not trying to make your job more difficult, they are only following EPA mandates.
The proper way to determine how much pesticide to put in the tank is to determine how much water is needed to spray an acre of pecan trees. However, we have found that the amount of water needed varies with both time of year and tree size. We use less water per acre during springtime casebearer sprays and more water per acre during late-summer weevil sprays. There are just more leaves to cover late in the season than earlier in the year. In addition, large native trees take far more water per acre to cover than a young orchard of grafted trees.
With experience, I have learned to assume we apply 100 gallons of water per acre in calculating how much pesticide to add to our 500 gallon tank. I then use the maximum recommended rate as listed on the pesticide label. In spraying the grove, I never rush the process. I drive slow enough to make sure to get complete coverage of the canopy. The leaves need to be covered, not dripping wet.