Texas Plains Pest Management: Few Immediate Threats but Keep Scouting

    General Status

    It is no secret that our crops, particularly cotton, are ‘running’ late this year. Most feel we are about 10-14 days behind schedule. I am not in panic mode yet. Our average last effective bloom date in the Plainview area is August 24th.

    Most decent to good cotton fields actually reach cut-out in most seasons around August 10th to August 12th. That can be our two week make up period and we have been having ideal weather this week to develop our crops. Even so, we may still need at least an average fall.

    The arrival of the sugarcane aphid has caused quite a stir, especially for growers with late planted sorghum still in the whorl, the fall army worm populations are growing concern, sorghum midge is already in the area, the bollworm population looks larger than we have seen in a few years, and we still have a fair number of cotton fields not blooming yet that remain at risk for the healthy fleahopper populations we have.

    We do have some crop management before us this year as we enter early August, or crunch time as I sometimes call it. This is a period when, if crops have made it this far and look ok or better, hours count for every decision and action we take in our fields.

    Cotton

    For the first time in several weeks, we did not have to recommend treatment for fleahoppers in any of our PPM scouting program cotton this week. We still have several fields at risk, but all but a few of these fields have already been treated. Still about 25% of our fields in general escaped without need of control measures.

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    While blooms are becoming more and more common, and we would really like to put this pest in the rear view, we will still have a few fields at risk that need to watched for these fleahoppers. These latest fields do not need anymore delay in fruit setting.

    In development, our fields ranged in stage from ¾ grown square up to 5.24 NAWF (nodes above white flower) on some of our dryland fields. The majority of our irrigated fields were in their second week of bloom or far enough along in their first for us to take NAWF counts with most coming in between 7 and 8.2 NAWF.

    Boll set from surviving squares looks pretty good so far, but we are picking up some very light to light damage incidental fruit damage from true armyworms and cotton square borers alongside some pure foliage damage from cabbage loopers too in non-Bt fields.

    Bt, even the older technologies, are holding these already sporadic pests in check very well but we should take note of populations larger than 50,000 foliage feeding worms per acre or if incidental damage to fruit intensifies from these pests to 6% of harvestable fruit. We are still monitoring fields for Lygus but have not noted any threatening populations yet.

    We are also on the look out for early bollworm populations. Most remain in corn but should be emerging soon looking for new host fields. This could very well be late corn or sorghum, but it could be isolated or attractive cotton too. In fact we did find a light egg lay in an isolated from grain crops cotton field with 3,375 bollworm eggs per acre.

    For exact details on this variety of pests, please consult our Managing Cotton Insects in Texas guide. For tips on how to scout for bollworms, Kate Crumley, EA-IPM Warton, Jackson, and Matagorda (and native of the Plainview area), produced an excellent ‘how to scout’ video on bollworms a few years ago:

    And here is a ‘how to scout’ video we made on Lygus scouting:

    Sorghum

    Our youngest sorghum is at V3 and our oldest is at late bloom with the majority in flag to boot but plenty of fields in between. We started picking up some sub-economic sorghum midge pressure in blooming sorghum with our highest field at 0.25 midge per head.

    Headworms were a common find in most booted fields with the population consisting of about 75% bollworms and 25% FAW (fall armyworm). Our heaviest population was well below economic levels so far with 0.17 worms per head but 0.1 was a pretty consistent find. Whorl feeding remains very common with FAW making up the bulk of the population.

    While this should be monitored closely, our damage has never gone above 2% foliage loss with about 30% foliage loss being the ET for whorl stage sorghum. Banks grass mites were a common find in most of our sorghum this week too, with very small, dime sized colonies on some of the lower leaves.

    Sugarcane aphids (SCA) in the area has been the attention grabber so far. We are steadily finding them in our post-boot sorghum but are still having difficulty in the more susceptible whorl stage fields. The SCA population is steadily increasing, but we have not found any at ET yet.

    I do expect some to reach threshold within 10 days despite some solid predation slowing them some. I have had several calls this week about heavy aphid populations on or about the flag leaf or upper whorl plants. These have all been misidentified corn leaf aphids, a nearly harmless aphid that helps build predator populations and should not be treated.

    Corn

    Our youngest corn is only at V7 stage while our oldest is in dough. The bulk of our acres were late planted this year, but are nearing tassel in a V12 to VX stage. We have quite a bit of pest activity in our oldest field, but nothing near economic levels. BGM have been on the increase and corn earworm (aka cotton bollworm and sorghum headworm) are infesting nearly 100% of the ears.

    The BGM remain below ET with a 1.5 field rating on our 0-10 damage rating scale with 3.5-4 being ET and we are noting a pretty large increase in mite predators. The earworms remain non-economical with typical tip feeding only.

    Disease pressure remains pretty light but we did find one late whorl stage field with some noteworthy southern rust on most of the lower leaves. This was not economic yet but certainly deserves to be watched closely, especially pre-tassel with tassel being an ideal treatment stage, if needed.

    Given the humidity, rainfall, and general environment this summer, seeing this light pressure is an honest surprise.

    General Pest

    Grasshoppers, while not at a plague level, are certainly prevalent in pockets, particularly near on in pasture or heavy, uncontrolled grazed, or shredded weeds. A few acres of grass for grazing and some foliage crops for hay have already required treatment.

    Keeping an eye on field margins, calculating grasshopper pressure in pasture, and giving an extra lookout in gardens and horticultural areas might be wise. I suggest keeping an extra eye toward gardens, fields, or horticultural plants in areas adjacent to freshly mowed or shredded weeds as these now displaced pests will move to the nearest vegetation in-mass as we eventually tame our wild weeds in the area.




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