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    Texas Plains Pest Management: Cotton Susceptible to Fleahoppers; Watch for Fall Armyworms

    General Status

    Hot and dry is the theme of the year so far. Early rains gave us quite a bit of hope, but they have not continued the way they did last year, and they were not really enough to break the drought situation. As a result, over 45% of our scouting program irrigated acres have now been failed and surviving dryland fields are rarer than a gentle rain cloud. These are all situations of not enough soil moisture and or not enough irrigation capacity to save the fields without environmental help.

    That being said, surviving fields are off and running with ample heat units to begin rushing through developmental stages. Grain crops are soaking all the moisture they can this week and likely will for the foreseeable future but many cotton fields are in a difficult position with decisions to be made. Keep the water on so as to not fall behind in irrigation and risk creating a wasteful, vegetative plant that will have no hope of keeping up with water needs later in the season or let the young plants root down a bit to keep them hardier and better prepared for what is to come.

    Waiting this year could risk making the plants wait too long in a ridiculous situation and lose yield potential due to wilting point issues if not endanger the stand of the field. It is a fine line with dire implications either way that even early PGR applications with heavy irrigations might not cover.

    The answer is likely different for each field, but some spoon-feeding cotton periodically early with limited 0.8-1-inch irrigations bi-weekly and not full irrigation capacity while its needs are low early in the season might hold more end returns now that we know we have no hope of building ever building a soil moisture bank to save for later needs. We not only need to watching fields for these agronomic issues, but weeds remain problematic, often coming through treatments, and a few insect pests might be looming soon.

    Cotton

    This week our surviving Plains Pest Management scouting program fields ranged in stage from al-most emerged up to ¼ grown square stage with most fields coming in around pinhead square. Fleahoppers were largest concern this week. Not because we had very many, but the cotton is at a very susceptible stage to their damage. Last season was a very heavy years for fleahopper pressure with well over 30 days of threat.

    More on Cotton


    What we will be facing this year remains to be seen but our counts have been light so far. Next week several fields will be large enough for drop cloth data collection which expands our ability to evaluate dozens of plants at once rather than with plant and terminal inspections alone. Inspections will still be needed for fruit retention/drop data, actual conformation, and additional pest population monitoring.

    Drop cloths, beat buckets, or sweep nets can be used to sample vast numbers of plants for pest populations quickly, but all data should be translated or referenced solidly to our research established economic thresholds (ET). For fleahoppers our ET is set at 25-30 infested terminals out of 100 with associated square drop that increases from 10% the first week of squaring up to 25% the third week. This week, most of our fields held no dropped squares but several ranged between 2 and 3% with no field reaching over 5%. We also noted no Lygus in field this week.

    Many area fields are still at risk for thrips damage with the ET still consisting of 1 thrips per true leaf stage. This week, we had no field over 0.38 thrips per true leaf stage and very few over 0.05 thrips per true leaf stage. This includes many fields in southern Hale that have not had a thrips treatment yet.

    Corn & Sorghum

    Our only PPM corn field was at V9-10 stage this week, still with no pests of note. This week we will be watching closely for establishing mite populations and fall armyworm, southwestern corn borer, and other whorl feeding pests moving in. Most of our replanted sorghum fields have failed to establish while our research plots at Halfway are at V9 stage. Pests were absent from this field also with no pest of note found. We will be on high alert for fall armyworm this week in our whorl stage sorghum for the next several weeks.

    Fall armyworms

    This week Dr. Pat Porter wrote an outstanding article cover-ing his trap numbers of FAW this week. Please do take a moment to catch this article here if you have not already.

    Unfortunately, Dr. Porter is not alone in seeing this high moth trend. Our numbers of FAW from our new traps this year are pretty high themselves. John Thobe, EA-IPM in Parmer, Bailey, and Castro, is running higher numbers to our west.

    Today we received word that Dr. Greg Sword’s numbers are high at College Station caus-ing some of his graduate students to coin the term ‘mothpocalypse’ to describe the situation that resulted in 2-6 larvae per whorl stage sorghum plant. Dr. Dalton Ludwick, district 11 entomologist, announced that he has a high enough population to begin several FAW efficacy trials in the Coastal Bend area. This FAW situation looks to be huge and at least Statewide.

    We can at least feel confident that whorl stage feeding in sorghum or corn from FAW is rarely economic, at least until we reach 30% foliage loss or so. That is very heavy indeed. We do need to be very aware of the fact that with populations that high in the area, it could be much more that the whorls at risk.

    If the FAW reach I high enough population that they are both in the whorl and out of leaves in numbers, they have historically proven to be able to completely skeletonize entire fields in a mater of hours if not days. It has been sometime since we seen this level of FAW danger in this area, but it has happened before.

    In this case, it will not only be whorl stage sorghum and non-Bt corn, but many if not all hay crops (coastal hay producers from farther south in Texas have been dealing with terrible FAW populations for a few consecutive years now) and just about all ornamental and garden plants at risk. For specific treatment recommendations, if needed, please refer to our Texas A&M AgriLife insect management guides.

    Grasshopper apocalypse in 2022?

    I do not know how widespread this is, but in southern Swisher I have noted on the ever-diminishing islands of truly green grass and Johnson grass clumps in bar-ditches an incredible population of grasshopper nymphs congregating on their preferred foliage. This week I took the time to count a typical square foot of area in these areas and counted 79 grasshopper nymphs of varying species.

    It is true that grasshoppers are usually higher in drought areas and years. This is because they only have one generation per year with eggs lain on the soil surface, typically near a food source. If rains are short and water never stands in the area where the eggs are lain, fewer eggs/nymphs drown. This is usually in conjunction with a reduced population of predators in that area who would normally be ready to devour several nymphs each if the area were at-tractive or could otherwise support higher populations.

    So, in drought areas and seasons, grasshopper population flourish without any checks or balances and develop into large insects that can better defend themselves before predator populations can build under the situations.

    What this means bottom-line level is that if the drought situation continues and these green islands falter to grasshoppers or drought, hungry waves of grasshoppers will eagerly flock to the nearest green vegetation with biblical plague like waves. We should not only be ready for this pest in production fields margins and hay crops when and if this move takes place, but yards, golf courses, gardens, and horticulture plants are all about to be in serious danger.

    We may have somewhere between a week to a month before we start seeing this apocalyptic wave of pestilence hits civilization in West Texas. If we can receive widespread rains the situation could be abated keeping the higher than normal grasshopper population spread out across pastures and in bar-ditches with predators hopefully reducing their number. Otherwise, we should prepare to receive some unwelcome chewing pests on just about everything green in the area




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