Addressing Early Season Pests

NORTH CAROLINA | Guy Collins

As I write this in late March, the North Carolina Department of Agriculture is in full swing with the cotton seed quality testing program as seed is moving into North Carolina more and more rapidly. By the time this article is read, planting should be largely underway in the state. With acreage being down, this will hopefully allow for more strategic planting into ideal conditions. Hopefully temperatures during May will bring ideal conditions and replanting won’t be a big issue.

It is important to evaluate stands in a timely manner (seven to 10 days after planting) so that action can be promptly taken, if needed, before the late May crop insurance deadlines or at least in time to replant and reasonably achieve ideal stands without substantially delaying maturity.

We don’t normally expect cotton to emerge to completion before seven days unless nearly perfect conditions prevail and cotton is planted shallow (less than a half inch) as it should be. By 14 days after planting into good moisture, a full stand should be present, so if it isn’t, replanting may be needed. The most common exception to this may be planting into very dry soils and waiting on a rain. Regardless, shallow planting is nearly always advantageous over deep planting, even when dusting cotton in.

Some of our research a few years ago suggested that replanting may be justified when 30% or more of the planted area is occupied by 3-foot skips. Fields that are noticeably worse than this threshold obviously need replanting if cotton was planted shallow and into good moisture and 14 days or more have elapsed. Fields that are very near this threshold often appear to be debatable so they should be evaluated thoroughly. Therefore, growers should focus their time and efforts on these “debatable” fields while avoiding wasting time making decisions on fields that clearly have either very good or very poor stands. guy_collins@ncsu.edu

GEORGIA | Camp Hand

There is still not much excitement surrounding cotton, so I imagine there will not be too much excitement surrounding the input costs and management of early season pests. However, if you have read my Specialists Speaking comments for the past few months, you have read what I have been telling growers: “If you decide to plant cotton in 2025, you have to make it!” Management of early season pests is crucial to making a crop in 2025.

At-plant decisions have to be made for thrips and nematodes. Utilizing resistant varieties or other at-plant treatments (seed treatment, in-furrow liquid or granular) are the main ways to handle these two pests, and the decision needs to be based on risk of yield loss and species in your field (with respect to nematodes). If you are planting in a heavy thrips window or in a nematode field, these are two things that cannot be neglected.

Most people are concerned about the situation surrounding weed management in 2025, with a major tool not available for growers to utilize. The emphasis in a weed management program should be heavy on residuals — two effective mechanisms of action at planting, overlapping residuals over the top and a layby application. We are very fortunate in Georgia in that we still have tools that work when implemented in a timely manner.

Timeliness is key. The worst pest management application a grower can make is the one they have to make twice — and in a year like 2025, we do not need to be making unnecessary trips over the field. Get out there, make the right decision on your place and implement that pest management decision in a timely manner.

As always, if you have any questions or need anything, please don’t hesitate to reach out to your local University of Georgia county Extension agent. We’re here to help! camphand@uga.edu

ALABAMA | Scott H. Graham

For many early season pests, management decisions are made when seed is ordered. Varieties (herbicide technologies, ThryvOn for thrips or nematode resistance) and seed treatments (thrips, seedling diseases) play a big role in mitigating many issues.

Planting date can also play a role in early season pests. Cool, wet conditions can exacerbate thrips injury and increase the incidence of seedling diseases. In some situations, dry periods can make other insects, like three-cornered alfalfa hoppers, worse as dying hosts on ditch banks and field borders aren’t suitable for the insects. Unfortunately, we can’t sit around and wait until things are “perfect” to plant (and we can’t get everything in on the three “perfect” days we get a year either).

The best way to address early season pests is to have a plan. That plan should include field history, such as grasshoppers or nematodes. Prepare to make decisions based on the risk you are willing to take (grasshoppers) or certainties (nematodes).

The next thing the plan should involve is a consultant or trained scout. There is no substitute for having someone walk fields weekly to provide reports and recommendations for insects, weeds and diseases.

Finally, the plan should involve reaction. If the recommendation calls for treatment, react as soon as possible. This year, we shouldn’t think about crop protection as a “cost” but as an “investment” in the crop. When following economic thresholds, crop protection materials consistently provide a return on investment greater than or equal to the cost of controls.

Let’s get the crop off to a good start and react as needed throughout the year! Reach out to your local Extension agent or specialist if you ever need any help! scottg@auburn.edu

MISSISSIPPI | Brian Pieralisi

It appears to be an early spring this year. As I write this on April 2, birds are chirping, trees are green, burndown is out, and cotton planting is right around the corner. Early season pests are always concerning, and a few tips can help avoid delays in maturity.

Most importantly, burndown and PRE applications will set the stage for weed pressure in acres that normally would be in a dicamba system. Starting clean will make it easier to stay clean without in-season dicamba applications.

For thrips, acephate will likely be used to some degree, but it’s worth noting that it is under evaluation with EPA and some thrips populations show resistance in Mississippi. ThryvOn and Intrepid Edge are still effective management tools against thrips damage during the early season.

Hopefully the weather will hold up and we can get this growing season underway during the first couple weeks of May! bkp4@msstate.edu

TENNESSEE | Tyson Raper

As I write this on the morning of March 27, the sun is shining and I’ve already shed my jacket. I hope, by the time you read this in early May, we have seen a window favorable for cotton planting. For acres that have been planted, we are likely moving quickly toward a period of time critical for thrips control.

Keep in mind that our entomologists ARE NOT recommending thrips sprays on ThryvOn cotton. For acres that are not ThryvOn, the best approach is to protect the plant from the emergence of the first true leaf until the emergence of the fourth true leaf. Physiologically, above-ground growth through this time period is very slow, but root growth is quite rapid. Because of this, we occasionally are tempted to make “revenge sprays” — after addressing the thrips population with an initial foliar spray, the slow growth rate allows injury to remain visible for quite a while and tricks us into thinking we need to re-spray.

Make sure thrips are again present at a treatable level before triggering a re-spray. Favorable growing conditions occasionally allow us to move through this window with a single spray. I’m hoping we find that to be the case for 2025. traper@utk.edu

MISSOURI | Bradley Wilson

As you read this in May, a good portion of our acres are likely being planted. Addressing early season pests is crucial for cotton producers in Southeast Missouri, as a minimal delay in maturity can impact cotton lint yields in this short-season environment.

The goal is to start with a clean field. Planting into fields with moderate-to-heavy weed pressure can harbor insect pests and reduce cotton plant stand.

The No. 1 insect pest during early development is thrips. Thrips control options include in-furrow insecticide at planting and foliar insecticide applications at the two-to-three-leaf growth stage. Limited options are available for thrips control, and reduced efficacy rates with acephate have been documented in 2023 and 2024. New-traited cottonseed technology has provided good control of thrips in Missouri. brwilson@missouri.edu

OKLAHOMA | Jennifer Dudak

The most notable early season pest we observe in Oklahoma cotton production is thrips. Although thrips may not necessarily be considered a major pest in cotton, poor growing conditions after emergence can lead to damage impacting a producer’s bottom dollar. Poor growing conditions include a period of cool, cloudy days that slow the growth of the plant. Weekly scouting is encouraged to ensure seed treatments (if utilized) are still effective. Forages like wheat and alfalfa are prime hosts for thrips that migrate into cotton fields looking for a fresh source of nutrients. It is important to be extra vigilant if you have wheat fields adjacent to your cotton.

When scouting, check the underside of the cotyledons and true leaves, as well as the terminal bud of the plant for the insect. Thrips like to “hang out” and feed in the terminal so carefully opening those leaves and observing inside is key. However, keeping track of thrips numbers through visual inspection of the plants can be challenging, especially in the delicate terminal tissue and with our Oklahoma winds. One method you could try is pulling up plants from different parts of the field (how many plants depends on your field size) and beating them into a plastic cup.

Keeping track of the number of plants you sampled, count the number of thrips you observe inside the cup and calculate how many thrips per plant you observed. The threshold is based on cotton stage and increases with the number of true leaves the plant has. The general rule of thumb is the number of true leaves is equal to thrips per plant threshold. For example, if the plant has two true leaves, the threshold is two thrips per plant. If the average plant in your field has two true leaves and you calculated three thrips per plant, it is likely time to spray. Once the plants reach the five to six true leaf stage, scouting and spraying for thrips is rarely justified economically.

Thrips color can differ by species but are usually yellow, light brown or a similar color to wheat straw. They are very small and cylindrical in shape. They also have rasping-sucking mouthparts and feed on the outer layer of tissue on the plant; this causes plant cells to burst then they suck up the released fluids for nutrients. This feeding causes dark brown spots that eventually turn a silver color on the underside of the leaf. Damaged leaves are cupped, crinkled and can have a leathery texture. If they damage the terminal bud by feeding, new growth and overall plant development can be delayed.

Other pests we are identifying in more cotton acres across the state are nematodes, both root-knot and reniform. Chemical control is an option, with aldicarb making its way back as trade name AgLogic and products like Velum. However, resistant cotton varieties on the market are very promising, especially when dealing with a reniform nematode infestation. If you suspect you have nematodes, please reach out to myself or Dr. Maira Duffeck, Oklahoma State Extension plant pathologist, for assistance in sampling and identification.

As we are pulling out and dusting off our planters, I want to wish our cotton producers a smooth and safe 2025 planting season. As always, I will continue to pray for rain and a prosperous year. jdudak@okstate.edu

TEXAS | Ben McKnight

As I write this in early April, recent rainfall in South Texas has brought some relief to very dry soil moisture conditions in the area. Despite some areas in the southern cotton production regions of Texas receiving several inches of precipitation, the drought monitor map still has these areas in drought conditions as more rainfall will be needed to replenish depleted soil moisture as the 2025 growing season progresses.

When visiting with growers about the many options of traits available in current commercial cotton varieties, I encourage them to select and utilize trait packages that will best alleviate pressure from common pests in their area. One example is early season thrips pressure, which can vary from year to year and from location to location. If thrips are typically troublesome for producers early in the season, selecting varieties with the ThryvOn trait can greatly assist in the management of these pests. My colleagues and I have evaluated many varieties with this trait over the past few years and the results speak for themselves in a year with heavy, early season thrips pressure.

Nematodes are another common pest in some Texas production regions. While nematodes are more of a season-long pest, the commercialization of cotton varieties with nematode resistance traits over the past few years has put another tool in our toolbox when it comes to nematode management. Trials conducted over the past few years evaluating these varieties in multiple locations with often heavy nematode pressure have demonstrated the value these traits can bring to your operation if nematodes are one of your top yield-reducing pests. bmcknight@tamu.edu

TEXAS | Ken Legé

As with most things related to West Texas cotton production, early season pest pressure greatly depends on rainfall and moisture. While we’re still celebrating the moisture we received across the region from the early November 2024 rains, which is safely stored deep in the profile, our top 6-inch to 12-inch soil layers are extremely dry. This scenario dramatically affects how our growers are attacking weed control and preparing for any insect pests.

Yellows are still an important part of the weed control strategy in West Texas, and normally those applications will have already been made, either broadcast and incorporated or through pivot or drip systems. Some growers have made the chemigation application, but many growers are reluctant to apply yellows when it is this dry at the surface, especially with no significant rain in sight. Adequate incorporation can be a challenge under these dry conditions. That said, yellows should still be on the list of necessary tools to use to battle weeds, as they are about 75% to 85% effective on pigweed when properly incorporated, which is the same level of control this herbicide group has always been…when properly incorporated.

Burndown applications typically use chemistries that need activation with water, which is a tremendous challenge this year in West Texas. Light water pivots sometimes only partially activate herbicides, and of course, we are left to Mother Nature to activate drip and dryland fields. Additionally, due to our dry conditions, many weeds have yet to emerge. We will receive rain at some point, and growers need to be poised to handle the weed flush that will, no doubt, follow the next significant rain event.

Of great concern is that this difficult pre-season drought will make in-season weed control even more crucial. Residuals are the key, but we still heavily rely on over-the-top chemistries like glufosinate, glyphosate and auxins. It has now become clear that in-season labeled dicamba will not be an option, and that has presented some growers with difficult choices to make. Some have opted to adapt to the 2,4-D tolerant Enlist system from Corteva/PhytoGen to enable in-season, over-the-top auxin applications. Many others are planning to use only glyphosate and glufosinate and their only over-the-top non-residuals and not deviate their variety choices. Proper timing, rates and carrier volumes will help make that system work better.

Because of the ongoing drought and heat in West Texas, we have been nearly an insect desert for the past few years. That’s not to say that we don’t have insect pests that exceed threshold, but rather, it is easy to get complacent about insects because they tend to be sporadic. The top insect pests for the Texas High Plains are thrips, cotton fleahopper and plant bugs. And even those pests can be inconsistent as to having levels above economic thresholds, which makes scouting even more critical. Occasionally, we will see aphids, grasshoppers and stink bugs make an appearance that warrants control, but those tend to be very spotty in distribution. One of the newest pests for West Texas is wireworms, which is generally associated with planting into a cover crop.

While most West Texas growers would like to have cover crops on most, if not all, their acres, many have difficulty balancing the use of water to sustain those cover crops versus the cotton crop. Where we do have cover crops, wireworm pressure awaits quite often. Insecticide seed treatments and some in-furrow insecticide applications have shown good efficacy for wireworms, but treatments once the crop is planted have proven not effective. Be prepared for those fields in which you will be planting into a cover crop.

See https://lubbock.tamu.edu/ for more information on all the early season pests we face in West Texas. ken.lege@ag.tamu.edu

ARIZONA | Randy Norton

Winter precipitation across Arizona during the 2024/2025 season was historically low. If it had not been for some late winter/early spring weather events, snowpack across the northern parts of Arizona would have been extremely low. This will obviously impact water availability for the coming growing season. Producers will need to make some tough decisions on acreage planted based upon water availability.

The other consequence of little to no winter precipitation in the lower deserts is the absence of vegetation (weeds) in uncultivated areas this winter and early spring. Oftentimes, these weedy areas will harbor insect pests. As the temperatures rise and the winter vegetation begins to dry down, these insects may migrate into nearby cotton fields. Management of early season insect pests is critical to help ensure vigorous early season growth and early fruit set.

A recent technology that has proven effective against early season insect pressure is the ThryvOn trait contained in several commercially available cotton varieties. The ThryvOn trait is available from a few different seed companies in locally adapted varieties. The primary and most extensive offerings are from Bayer as Deltapine varieties. There is still considerable work being done to determine the overall economic benefit of utilizing this relatively new technology in our Arizona production systems.

Our University of Arizona Extension specialists continue to develop locally adapted recommendations for use of this technology. Yield and fiber quality is still the driving influence in variety selection, but each year we are seeing additional ThryvOn varieties that perform well in our environment. For more information on this topic and others go to our website at https://extension.arizona.edu/topics/field-crops.
rnorton@cals.arizona.edu