Thrips in Cotton and Peanuts

Jeff Gore, Research and Extension Entomologist
By Jeff Gore, Research and Extension Entomologist, Angus Catchot, Extension Entomologist and Don Cook, Research Entomologist May 17, 2013 15:27

I have been asked several times over the last week about the need for thrips control now that we have more optimal planting conditions.  This is a good question and I will attempt to provide some valuable insight about thrips control in both cotton and peanuts.

Cotton

In general, we get the most benefit from an at-planting insecticide at the earlier planting dates in cotton.  Compared to most other crops, cotton comes out of the ground and just seems to sit there for a couple of weeks.  This is compounded when environmental conditions are not optimum for cotton seedling growth and thrips become a much bigger issue. As the temperature warms up and we have good growing conditions, the plants can handle more thrips because they are growing at a faster rate.  Basically, the plants can outgrow the thrips when they have warm temperatures and good moisture.  Even though most of our cotton this year is being planted later than normal, it will become even more important to keep a close eye on thrips.

We are not as likely to see thrips impact yield as much as they would for cotton planted in mid-April.  However, they can still delay maturity if numbers are too high.  As we have talked about the last couple of years, those delays in maturity can have a big impact on tarnished plant bug management later in the year.  The seed treatments should do a pretty good job controlling thrips and all of the rainfall we have been getting will help keep populations beat back some.  Despite the good growing conditions, it is going to be important to maintain a good scouting program and make applications when they are needed.

Peanuts

Thrips management in peanuts is a little more complex because they transmit tomato spotted wilt virus in peanut.  Fortunately, most of the runner varieties that we are planting are resistant/tolerant to TSWV and it is not as big of a concern anymore.  It is still important to maintain good seedling growth in peanuts, especially as planting date gets pushed later into the season.  A good at-planting insecticide is very important for early season insect management in peanut.

There are several options available in peanuts and I have had several questions about all of them over the last couple of weeks.  All of them have their strengths and weaknesses.  Thimet (in-furrow granule), Admire Pro (in-furrow spray), and Cruiser (seed treatment) are all good options and should provide adequate control of thrips.  Foliar sprays are another option, but they don’t usually provide the same level of control that you can get from an at-planting insecticide.

The Impact of Wheat

A lot of the wheat throughout the state is starting to lose it’s dark green color and will have an impact on thrips populations.  As the wheat begins to turn more of a pale green and eventually dries down, large numbers of thrips will begin moving out of the wheat and into other crops.  In a more “normal” year, the majority of those other crops have been planted for several weeks and are at a stage where they are no longer susceptible to injury from thrips.  With the delayed plantings of both cotton and peanut, there is a greater chance of those crops being at a highly susceptible stage when the wheat dries down.

It is going to be very important to keep an close eye on all crops that were planted this week or will be planted in the next couple of weeks, especially those that are in close proximity wheat.  In general, most crops can handle some thrips pressure with no yield losses or delays.  However, they can all easily be overwhelmed and need to be scouted on a regular basis.

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Jeff Gore, Research and Extension Entomologist
By Jeff Gore, Research and Extension Entomologist, Angus Catchot, Extension Entomologist and Don Cook, Research Entomologist May 17, 2013 15:27
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