It’s not new, but the Kurtomathrips, which has not been an identified cotton pest for decades, is showing up in “extremely high numbers,” in the Texas Southern Plains.
Texas AgriLife Extension entomologist David Kern says the thrips species, which was identified in Arizona back in the 1920s, is small, about the size of spider mites, and can “cause damage similar to spider mites.
“We can control them,” he says. “It’s just a matter of picking them up.”
Kerns says he’s not certain how badly Kurtomathrips would damage healthy cotton, but “we can see injury on cotton with limited water.” And that describes a lot of cotton acreage in the Texas High Plains this summer
Manda Anderson, Extension integrated pest management specialist in Gaines County, has received several calls regarding control options for Kurtomathrips infested fields.
“They have been identified in fields in Gaines County. One field is approximately eight miles west of Seminole and the other field is in far northwestern Gaines County. They have also been reported in Lubbock County and far northwestern Yoakum County. This pest is widely distributed and could be found in any field. The highest populations tend to be in an area of a field with a skippy stand, drought stressed, or suffering due to other factors.”
Growers do have control options.
“Scott Russell, Extension IPM agent for Terry and Yoakum Counties, has come up with some pointers to help producers determine whether or not an insecticide application is justified,” Anderson says.
According to Russell, points to consider in making the decision to treat include:
- What is the yield potential of the field? Low yielding fields (less than 500 pounds per acre) may not recover the economic input of an insecticide application. Also consider other inputs up to this point, plus harvest costs. The chemical costs range from $2.00 to $6.00 per acre. Application costs also must be counted. The yield protected must cover this cost.
- What is the stage of growth of the cotton? If bolls are mature—Cut the boll open and determine if seeds have well defined cotyledons and seed coat versus those which are watery seeds—they may not be significantly damaged by the defoliation. If there are numerous bolls left to mature, treatment may be justified. These immature bolls should yield enough to cover treatment costs (as in point number 1 above).
- Will you utilize harvest aids or not? If you are planning to use harvest aids, you’ll need some leaf surface area to absorb the materials.
Anderson says several insecticides are effective on the pests. Results from a recent trial show Intruder (Acetamiprid), Orthene (Acephate), and Trimax Pro (Imidacloprid) had the greatest impact on the Kurtomathripsat five days after treatment.
“The untreated plots still had approximately 390 thrips per five leaves,” she says. “This is a very destructive pest. Once a plant is infested, the thrips will keep feeding and reproducing on that same plant, even though the plant appears to have no more substance for the thrips to feed on and it is completely destroyed. It is truly amazing, the number of thrips that we are finding on dead looking plants.”
Growers interested in learning more about the pest may attend a turn-row meeting at 10 a.m. Aug. 24 at CR 108 and Hwy 62/385 Intersection (approximately three miles north of Seminole). The field is on the south side of Wallach Concrete.
“We will be looking at a field infested with Kurtomathrips during this short meeting,” Anderson says. “Please feel free to contact Scott or me if you have any questions.”