With almost half of Alabama's peanut crop rated in poor to very poor condition, many of the state's producers face an uphill battle as they enter harvest season. But scattered showers in August and September could salvage a portion of the crop.
Two weeks of temperatures ranging from 97 to 107 degrees during mid-August has had a drastic effect on the crop's fruit set, says Kris Balkcom, Auburn University Extension peanut specialist.
It has been especially dry in east-central Alabama, he says. “We've been getting a lot of calls lately about ‘pops’ (empty pods), and growers want to know if they should put out more calcium. The fact of the matter is that you had adequate calcium out there already. When it's this dry, the calcium is there, but there's not enough moisture in the soil to allow it to get into the nut, so you'll get pops,” said Balkcom during a recent crops tour in the eastern part of the state.
This could be a year in Alabama when there are two distinct peanut crops, he says.
“If it starts raining now, we'll have a large gap from the time when the plant began blooming and this long dry period,” he said in late August. “We'll have to make a decision on which crop we'll concentrate on harvesting. Most of the time, when we get adequate rainfall, we have a fruit set all the way through the season. Those on the taproot will stay there and mature.
“But in years like this one, you set your crop early when you had adequate moisture. As we went through the season and it turned off dry, that peanut plant tried to hold in as much moisture as possible and feed water to those pods. As it has stayed dry, it eventually ran out of water and the flow of nutrients stopped — that causes those pods to turn loose in the hull. You don't want that to happen if they're not mature by that time. If it starts raining again, they'll fill up with water, sprout and rot off,” says Balkcom.
Dry weather conditions have created some difficult decisions for growers about how much to put into this year's peanut crop,” says Austin Hagan, Auburn University Extension plant pathologist.
“You don't know if you'll get your money back, particularly with respect to leafspot sprays. In areas where producers haven't been growing peanuts in the same field, leafspot and some of the other diseases might not be a serious problem. If there isn't too much leafspot, you have some options on fungicide sprays,” says Hagan.
If one or two rains might make a difference in yield potential, Hagan says he wouldn't quit spraying altogether. “To hold our costs in line, and mainly target leafspot, we have products like Bravo Ultrex and the chlorothalanil generic fungicides. If it's dry in your area, you can look at reducing the rate to 1 pint per acre.
“There are other materials out there. If you're looking at picking up white mold control and it does rain, there's Folicur and its clones. We have other materials that are more appropriate for areas where disease pressure is more severe,” he says.
Growers can stretch the intervals between sprays, especially for products like Bravo and other chlorothalanil fungicides, says Hagan.
“You apply these to the foliage, so they're not going anywhere. They have residual up to two and a half and maybe three weeks if it doesn't rain. Folicur will last about 10 or 11 days. But if you do stretch that interval, you need to watch the weather. If you see a good chance of showers for a couple of days, you need to spray in front of the rain. We could get a heavy rain, and you could be kept out of the fields for a few days. Then, three weeks later, you could be having problems with leafspot and leaves would be coming off the plants. There's not much you can do at that point,” he says.
Even though there hasn't been one to impact Alabama in a couple of years, tropical storms still could be a factor to consider late in the season, says Hagan.
“If you know one of these storms is coming, and you sprayed a fungicide within five to seven days, you're probably okay. If it has been 10 to 12 days, spray in front of the storm. A chlorothalanil product will last through that type of weather pattern. If you get behind, you may need to use something like Folicur, Tilt or Propomax and tank-mix it with some chlorothalanil. You do get some kick-back activity from those systemic fungicides that you won't get from chlorothalanil,” he says.
Late-season insect control is another consideration for peanut producers, says Ron Weeks, Auburn University Extension entolomologist.
“There are times in the year when we need to focus on certain insect pests,” says Weeks. “Some occur in the early and mid-season, and some occur late in the season. With peanuts being an underground crop, soil insects are of major importance during the final part of the season. As peanuts set the pods and mature, that's when the greatest yield loss can occur.”
Late in the season, and especially during a drought year, growers should be concerned about the amount of foliage on the peanut plant, he says. “We want to be more conservative with foliage loss. Peanuts generally can tolerate from 30 to 35 percent foliage loss without any impact on yield. There's still enough foliage to make a good crop. Foliage loss from insects is different from foliage loss due to leafspot. With insects, it's a matter of a loss of green tissue to help keep up the plant. Disease loss has a physiological effect on the plant, so the yield loss is greater,” says Weeks.
Loss from foliage feeders won't cause the pods to come off the plant as they do with leafspot defoliation, he says.
“We're in a drought, but there are a few spots in the state where peanuts are doing relatively well,” says Weeks. “In most areas, peanuts have had a few showers and are doing reasonably well for the conditions we've had. They've set a few pods. The foliage is not as fully developed as we'd like for it to be.”
In a drought situation, some insects can be more of a problem than others, he says. “In peanuts, we try to minimize insecticide applications during drought conditions. We do this to conserve beneficial insects. Spider mites especially can be a problem in peanuts. We generally find them whenever we have previously used insecticide sprays, and certain insecticides can be more of a problem than others. We want to minimize insecticide sprays as much as possible. If worms were to move in on the crop, we wouldn't want to see much more than 30-percent foliage loss,” he says.
Weeks says he would not recommend that growers routinely put an insecticide in with a fungicide treatment just because there is slight worm damage or a few leafhoppers or three-cornered alfalfa hoppers in the field.
“We're at the point to where we need to quit worrying about those things. They may still be out there, but any damage they cause from here on out will be superficial and won't greatly affect yield. And those sprays may set you up for more serious problems, such as foliage feeders or spider mites.”