Arkansas cotton is crawling with thrips. “The current infestation is as bad as we’ve seen in a very long time,” said Gus Lorenz at an Integrated Pest Management meeting in Crawfordsville, Ark., at the end of May.
“There have been a bunch of calls from farmers saying, ‘My Temik quit and my seed treatments aren’t working.’”
The Arkansas Extension entomologist said at the same time, “we’re running a lot of trials with these products. Those products haven’t quit working, they’re just overwhelmed. From 75 percent to 85 percent of our acreage has been treated at least once — most twice, by now — with foliar applications for thrips.”
Lorenz said “fairly good control” was being seen from Bidrin and dimetholate. A bit of Orthene is being used as well.
“I’d caution anyone about their treatment choices. It’s getting hot and dry and we’re getting many reports on spider mites in northeast Arkansas. We certainly don’t want to flare those. Of the three (aforementioned products), Bidrin and dimetholate are least likely to flare secondary problems like mites and aphids.”
On the new Bidrin label applications are limited to 0.2 pound prior to bloom. So in most situations, producers can make only one application.
“Make your applications as wide apart as possible and get the biggest bang for your buck.”
There are also some rather severe mite infestations on cotton. The products that have looked best on early mites include Kelthane, Zephyr and Zeal.
“Zeal’s cost was cut 25 percent this year. All three of those products can offer good control if you have to make an early-season application.
“Catch the mites as early as possible. Don’t wait on them. Don’t wait on a lot of foliar symptoms to develop. You must be proactive and knock them back before they build to levels that will really cause problems.”
There are reports that aphids are beginning to build in spots. Watch closely for those because “the hotter and drier it becomes, the worse the aphids will be.”
Lorenz has also been walking rice fields.
“We’re researching some seed treatments. Hopefully, we’ll have some promise for those with rice water weevils and grape colaspis. Some seed treatments appear to have some promise for the future.”
But the most alarming thing over the last couple of weeks is the number of rice water weevils. Newly-flooded fields have “extremely high levels” of the pest.
Unfortunately, control options are limited. Once fields are flooded, “you must react in the first seven to 10 days to make a foliar application of a pyrethroid — Karate or Mustang Max. The only other possibility is to draw all the water off and let the soil dry. That means you have to let the ground crack before flooding again.”
Neither of those methods will make the field weevil-free. “But hopefully they’ll do enough to push the problems back. It seems with the cost of diesel, it may be cheaper to go ahead and make a foliar application on the pest adults. And we’re seeing a lot of adult weevils, right now. They are no trouble to find and they’re mating.”
Chuck Wilson emphasized the need to control adult rice water weevils. “Once they lay eggs and they hatch into larvae, the only option is to drain the rice,” said the Arkansas Extension rice specialist.
“Our handbook recommendation is to hit them in the first seven to 10 days after the flood. The label, however, recommends ‘as early as seven days prior to flood.’ I’m not convinced that’s the road to travel. The only time I’ve seen that work is after a lot of rain or if the field has been flushed. You draw in the weevils before the flood.”
As for corn, the southwestern cornborer is a lurking menace. “We’re not catching a lot of them in our traps,” said Lorenz. “This first generation coming out doesn’t appear to be too bad. But pay attention to trap counts. Call your county Extension agent and check what the trap counts are.”
The second generation of the cornborer is of special concern and “normally, those hit at the end of June/first of July. We want to key on those.”
Compared to other crops, Arkansas soybean have had little bother. Unlike wheat and corn, there were just a few soybeans planted in the state when the Easter freeze hit.
Over 50 percent of the state’s soybean acres were planted in the last two weeks of May, said Jeremy Ross, the new Arkansas Extension soybean specialist. “We were behind the normal planting rate until (mid-May). Now, we’re actually about 16 percent ahead of our planting five-year average. Planting has slowed since it’s become drier in the last few days. Plus, the last 10 to 15 percent of the crop will be behind wheat — so we have to wait until the wheat’s out of the field.”
On May 12, Asian soybean rust was reported in a kudzu patch in New Iberia, La., west of New Orleans.
“The thing that’s concerning about this is it’s 53 days earlier than it’s been found before. Everyone says it takes about three years for this disease to build up enough to really cause problems. This is the third year we know it’s been in the United States. So, we’re monitoring 21 sentinel plots scattered across the state, along with kudzu plots. We also have spore traps we’re checking on a weekly basis.”
The last couple of years, conditions haven’t been conducive for the development of ASR. Unless there’s a major change, “we probably won’t see it coming into our fields early. Most likely, it’ll show up late and not be much of an economic problem.
Following the Easter freeze, “we found out that rice is resilient,” said Chuck Wilson, Arkansas Extension rice specialist. “In my opinion, we’ve done extremely well considering the weather. There has been some replanting, but all in all, the crop has recovered and mostly looks good.”
There have been a few incidents of zinc deficiency. A week or 10 days later after flood, deficient crops begin to “bronze a little, get a little yellow at the base and leaves. And cold weather-stressed rice just makes it look even worse.”
By late May, earlier-planted rice fields had been flooded for two or three weeks. “Those will be approaching mid-season before we know it. At the same time, some rice fields haven’t been planted yet.”
Much pre-flood fertilizer is being applied. Wilson knows “the high price of urea has made growers nervous. But if the crop is going to be made, urea is necessary.”
Drift problems are already common, said Bob Scott, Arkansas Extension weed specialist. “We were covered up early with glyphosate drift complaints on rice. Until we get a herbicide-resistant rice, this will continue to be a problem. We simply cannot spray glyphosate with the wind blowing towards rice.”
After convening a drift task force over the winter, the Arkansas Plant Board is watching the drift situation very closely, warned Scott. “The board has already put in more education-based regulations. But I can see more serious steps coming if the number of drift complaints continue. And we’re just now moving into the first glyphosate application on soybeans. I hope everyone is careful near rice.”
Scott also provided an update on sodium chlorate. “Several years ago, the EPA told us we’d gotten our last Section 18 on sodium chlorate for wheat. They basically told us not to ask about it again.”
But following the Easter freeze, “we thought we’d try again. However, I just got a call saying EPA had denied our request. If you were waiting on that as a harvest aide for wheat, we were shot down. If a company would spend the money towards getting a label, they might reconsider.”