Texas LRGV Cotton: Heavy Boll Loads, Late Season Thrips

    Cotton loaded with bolls. Photo: Jerry Stuckey

    General Situation/ Harvest

    Another very hot and windy week. This week we had temperatures ranging from 98 -101 F and our nights have been steadily at 78-80 F. We are forecasted for more intense heat next week with temperatures forecasted to be at 102- 104 F.

    Growers have been harvesting corn and grain sorghum diligently for the last few weeks trying to finish up harvest. Both grain sorghum and corn yields have varied due to the drought we had early on and then rain showers in some areas and light rain fall in others.

    In irrigated grain sorghum I have heard yield ranging anywhere from 2300- 5000 lbs./ acre. Most irrigated sorghum varieties though seem to be between 3000 and 4000 lbs./ acre. In dryland sorghum yields have been between 1200- 2600 lbs./ acre.

    In irrigated corn yields have ranged from 5,000-10,000 lbs./acre. For irrigated corn it seems that some of the highest yielding corn was planted behind vegetables. In dryland corn yields have been between 2200-3900 lbs./ acre.


    We are seeing a lot of open and cracked bolls throughout the Valley’s cotton. In both dryland and irrigated cotton boll set looks very good; in some varieties, plants are falling over from heavy boll set. Most growers are a week to 3 weeks from applying a defoliant while others are further behind.

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    Despite the maturity of cotton in the Valley we are still experiencing heavy pest pressure in some areas, but most the Valley’s cotton fields are very clean.

    In La Feria and Mercedes areas I was picking up on some medium to high whitefly pressure depending on what field cotton you were in. For late season cotton it is important to monitor and keep whitefly pressure under control to avoid the sticking honeydew they secrete which then causes sooty mold to grow and can stain cotton lint.

    In La Feria and Rio Hondo was seeing a few Verde bug in late season cotton but for most fields’ bolls are mature and not soft enough for them to puncture.

    In the past 3 weeks I have received reports of high thrips pressure in cotton from several crop consultants. It was very interesting because we have never experienced late season thrips pressure like this in cotton and it wasn’t until this week that you could really see the damage this late season thrips had done.

    The cotton field’s leaves where fed on so much by these thrips that the leaves began to turn bronze looking and some fields were so severe that they looked as if defoliant had been applied when there had not been.

    More on Cotton

    My colleague, Dr. Holly Davis, and myself have looked at several fields, collected thrips and have made a preliminary identification but are waiting on confirmation from an out-of-state specialist and will get that info out soon. In the meantime, know that this is indeed thrip damage.

    These thrips are more yellow in color and like to feed right along the undersides of the midveins really tucking up under hiding on the cotton leaf and as they feed they turn the leaf a bronze/brown color, very different from early season thrips that turn the leaves greyish/silver. Most growers will not be spraying since they are a week away from defoliation.

    Other growers along the river though who had been experiencing these thrip populations in the last 3 weeks have had to spray and are receiving good control with acephate (Orthene) and dicrotophos (Bidrin).


    In sesame many fields across the Valley were very clean. Most are past or right at cut out. We do however have late season sesame that was planted, and some had to be sprayed for sesame leafroller in the Hargill area this week.

    In late season sesame we will have to be on the lookout for mirid plantbug pressure as I saw some mirids feeding at the growing point in late season sesame and populations of mirids in past years are high in the month of July.

    For those who did not see in last week’s Pest Cast, Dr. Holly Davis has made a very interactive 6-minute video showing SLR in the field and explaining their biology and how to manage them.


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