Thrips massing: Arkansas cotton desperate for water

For Arkansas' cotton crop it's been a spring of wild swings. “It's hard to catch our balance. So far, we've had the coldest temperatures (several nights, temperatures dipped to 39), and we've had very high temperatures,” said veteran east Arkansas consultant Bob Griffin, in early June.

“I recorded 97 a couple of weeks ago. Then, in early May, we had extreme rains around Marianna. It may not have been the wettest ever, but it was wet enough to keep us out of the fields. And now (into the second week of June) it's drier than I ever recall. We've seen major extremes in the last few weeks.”

The cotton crop has yet to find its sea legs. As it crawls towards first bloom, Griffin isn't the only one concerned. “Node production has slowed, and that's a major concern,” said Bill Robertson, Arkansas Extension cotton specialist. “For a while, we had a node produced every four to four and a half days. But over the (first week of June), that slowed, especially on early-May-planted cotton. If we don't get a rain over the next couple of days, we'll start irrigating in earnest.”

In most years, as long as the crop puts on nodes close to the normal rate, Robertson doesn't fret.

“I like a new node every 55 to 60 heat units. If it dips below that a little, it's no big deal. When it's moist and warm, it's not uncommon to see two nodes every five days. Lately, we've been seeing two nodes every nine days or so. In some fields over the last week, it's been hard to see where plants have put on a new node.”

Griffin, who works large cotton acreage in Lee and Phillips counties, is “very worried” about cotton near squaring. “It takes 25 days from the time a square develops until bloom. If cotton is progressing as it should, it'll add a node every two and three-fourths days. We were doing that until a couple of weeks ago. Now, we're putting on a node every four to five days. We all know it is important to have as many nodes above white flower (NAWF) as possible when bloom occurs. That's our crop's potential.

Griffin is advising his clients to irrigate. “This is two weeks earlier than we've ever watered. We're already running pivots and will start furrow irrigating in the next couple of days. If we don't, we're heading for a crash, and our crop yield could be cut in half. We need a rain badly.”

Parts of east Arkansas — including fields worked by Griffin — received rains over the June 11 weekend. But it wasn't enough. “We got anywhere from 0.5 inch to 2 inches of rain in some of the fields. Some still didn't get rain. Even where we got a couple inches it's dry again. Some dryland cotton fields got no rain and those are looking bad. It's critical for us to keep pumping the water where we can.”

Much of the state's early-May-planted cotton should be squaring in mid-June. If it isn't, producers need to irrigate. And if it is squaring, “we need to water anyway because we don't want to let squaring cotton stress,” said Robertson. “Yield-wise, we still have time. But with the pre-square cotton, we're losing days on the front end that we'll never get back.”

Because of staggered planting and cold temperatures, cotton maturity is inconsistent. “It's all over the place,” said Robertson. “I've tried to estimate when we'll hit pinhead square. I think we'll be a solid week or 10 days later than normal.”

With cotton growing slowly, pests are a problem. Normally at this time of year, cotton has outgrown the thrips threat.

At first, the thin stands Griffin saw didn't worry him much because the plants were healthy. But then thrips arrived in mid-May.

“It's kind of strange. We found out thrips come from places besides wheat fields. The weeds drying down due to lack of rain have put them on our crops big-time. We've got a problem as bad as or worse than I've ever seen before.”

Griffin is responsible for fields planted in treated seed. Some of those fields were sprayed for thrips 10 to 14 days after planting.

“That's very unusual. Most of the fields I'm seeing this on have maybe 20 to 30 percent of the field needing protection. That leads me to believe — and I may get calls and grief over this, but the truth is the truth — there are some gaps in our seed treatments. In other words, for 70 to 80 percent of the plants there'll be no blemishes on the leaves and no thrips. But that other 20 percent of the plants are being hammered, crinkling leaves. The only difference we can come up with is a lack of treatment on the seed.”

Griffin first saw this on cotton less than a month old. “You expect the seed treatments to last only three to four weeks anyway. But now I'm seeing thrips on one-leaf and two-leaf cotton on almost every plant.”

Both men suspect there are several variables at play. “It's extremely dry, so the treatment material isn't being activated like it normally is,” said Griffin. “It also seems we've got extremely high thrips numbers. Yesterday, using a box, I shook one plant and counted 126 thrips. I've never seen anything close to that number on one plant. The most I've seen before is 15 or 20 thrips. On the average, that field had 25 to 30 thrips per plant. This is a field of treated seed, so I was amazed. It seems the further we get into the season, the worse the thrips get. Thrips will delay maturity of our cotton, no doubt. I hope that doesn't put us behind the eight-ball.”

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