Early-Season Cotton Seedling Injury Observed in Scurry County

I received a call this week regarding below-ground injury to young cotton seedlings in fields near Snyder in Scurry County. Given the excellent soil moisture conditions this season, which generally favor the activation and performance of insecticide seed treatments, the amount of seedling injury observed was somewhat unexpected. 

During field inspections, the first insect activity that stood out was the presence of numerous Blapstinus beetles (Fig. 1). These darkling beetles are about 1/4 inch long, dull brown to black in color, and flightless. They are commonly found moving across the soil surface or hiding beneath soil crusts near the base of cotton plants. Blapstinus beetles feed on young cotton seedlings, typically slightly below or at the soil surface (Fig. 2), and can occasionally contribute to stand loss when populations are high. 

Fig. 1 Blapstinus darkling beetle

Fig. 2. Chewing injury to cotton seedling

We dug around affected plants to assess below-ground injury and recovered several false wireworms from the soil (Fig. 3). Although false wireworm larvae can be difficult to identify morphologically, previous work in Martin County, where similar larvae were reared to adults, suggests these specimens were likely larvae of sand darkling beetles in the genus Eussatus (Fig. 4). These are among the most common false wireworms in the Texas South Plains and are frequently associated with seedling injury, particularly in dryland cotton. The larvae feed below ground on germinating seed, roots, and hypocotyl tissue, resulting in reduced vigor, and skippy stands. 

Fig. 3. False wireworm larva

Fig. 4. Sand darkling beetle (photo: Pat Porter)

When asked about the insecticide seed treatment, the grower indicated that the seed had a "premium" treatment package but was unsure of the specific active ingredients and application rates. 

This highlights an important point. Growers should not assume that a premium or elite seed treatment package automatically provides adequate protection against early-season insect pests. Seed treatment trade names often do not always reveal which insecticides are included or the rates at which they are applied. For example, imidacloprid may be included in a package, but the rate can vary considerably. Some treatments contain only storage rates intended to protect seed quality during storage, while others contain field-use rates designed to suppress early-season insect pests. These details are often difficult to find, so growers should verify the active ingredients and application rates with their seed company representative before planting. If stand establishment issues arise, it is also worthwhile to verify exactly what seed treatment package and rates were applied. 

There are no effective rescue treatments for wireworms or false wireworms. However, if the observed injury is being caused by Blapstinus beetles, a timely foliar application of pyrethroid insecticide will help minimize additional damage. Foliar applications of systemic insecticides such as imidacloprid will not provide significant benefit against Blapstinus beetles or against below-ground wireworms and false wireworms. 

For fields that require replanting, make sure the selected seed treatment package includes a full field-use rate of insecticide. Although imidacloprid seed treatments are primarily intended for thrips management, they may provide some suppression of wireworms and false wireworms and are recommended over no insecticide seed treatment. Additionally, if beetles or wireworm larvae are active in field, an in-furrow application of imidacloprid plus pyrethroid insecticide should be considered.

South Plains Cotton: Early Season Insect Management Considerations

As we approach cotton planting season, one of the common questions is whether standard imidacloprid seed treatments will control wireworm and darkling beetle injury to cotton seedlings. In short, imidacloprid seed treatments are designed primarily for thrips control. While they may provide some activity against secondary pests, they are not effective against wireworms below ground.

However, when adequate soil moisture is present to activate the seed treatment, we have seen imidacloprid help suppress injury from above-ground Blapstinus darkling beetles. These beetles are about 1/4 inch long and are commonly observed chewing and girdling stems of young cotton seedlings at the soil surface.

If darkling beetle activity and stem injury are present, a foliar pyrethroid application is the most effective treatment option. Another common question is whether foliar-applied imidacloprid will control these beetles. Because imidacloprid is systemic, beetles must feed sufficiently on treated plants to receive a lethal dose, which limits its effectiveness in this situation. If targeting darkling beetles, a pyrethroid is the better foliar option. Imidacloprid generally performs better as an at-plant, in-furrow treatment than as a foliar spray against early-season pests.

For thrips management, imidacloprid seed treatments continue to provide good control and may be sufficient under low to moderate thrips pressure, particularly in areas south of Lubbock. However, high thrips numbers are already being observed in northern areas on the limited vegetation available under ongoing drought conditions. These thrips will readily move to cotton as soon as seedlings emerge. As a result, early-planted cotton may require an additional foliar treatment on top of the seed treatment.

For foliar thrips control, both acephate and dicrotophos (Bidrin) remain effective options. In our region, acephate continues to provide good control, unlike some areas of the Cotton Belt where thrips populations have developed reduced susceptibility. Although acephate is effective and relatively inexpensive, it has shorter residual activity and is less rainfast than Bidrin. Those factors should be considered when making treatment decisions. Vertento is another effective option for thrips and provides a different mode of action than acephate and Bidrin. However, it is going to be more expensive than those products.

When both thrips and darkling beetles are present, a tank mix of acephate and a pyrethroid should provide effective control of both pests.

Blapstinus darkling beetle

Blapstinus beetle injury

Update on Cotton Jassid: A New Pest of Concern in Texas Cotton

We are closely monitoring the recent invasion of cotton jassids, Amrasca biguttula Ishida (also known as the two-spot cotton leafhopper) in Florida, Georgia, Alabama, and South Carolina and we are keeping a close watch for this pest in Texas. In Texas this pest has been detected on hibiscus in big box store nurseries in McAllen, Weslaco, Harlingen, Victoria, San Antonio, Cedar Park, College Station, Waco, Longview, and El Paso, but has not been detected outside of these nurseries. It appears that infested hibiscus plants were shipped from South Florida for sell throughout much on the southern U.S. The Texas Department of Agriculture is taking steps to eliminate this potential source of cotton jassid, and the situation is being investigated by USDA-APHIS. Whether or not this incident results in establishment of this pest in Texas remains to be determined.

Cotton jassids (Photo: Scott Graham, Auburn University) 

Description  

Adult cotton jassids measure approximately 1/8 of an inch (2-3 mm) in length and are pale green with yellowish-green wings. They can be distinguished from other leafhopper species by a prominent black spot on the apical area of each forewing and, often, by two dark spots on either side of the head. The markings sometimes can be faint or absent. Therefore, definitive morphological identification requires dissection and examination of the male genitalia by a specialist or confirmation through molecular testing. The eggs which are laid within the veins and midribs of leaves are yellowish-white, oblong, and less than 0.04 inches (1 mm) long, nearly invisible without magnification. 

Newly hatched nymphs are wingless, pale green, and highly agile, often scuttling sideways or dropping from plants when disturbed. They are very small, typically less than 0.05 inches (1.27 mm) long—and difficult to distinguish from nymphs of other species. When disturbed, both adults and nymphs exhibit distinctive sideways movements and quick hopping behavior. 

Adult cotton jassid (Photo: Isaac Esquivel, University of Florida)

Jassid nymph (Photo: Isaac Esquivel, University of Florida)

Established distribution

The cotton jassid’s native range extends from Iran to Japan and Indonesia. It is a serious economic pest of cotton in the Indian subcontinent. In 2022 and 2023 it was reported as a serious pest of cotton in West Africa. It was found in Puerto Rico in 2023, followed by other Caribbean Islands and Florida in 2024. By 2025, infestations had been reported in multiple counties in Georgia, Alabama, and South Carolina. 

Life cycle

Majority of the information comes from research conducted in the native range of pest. As per the literature, female cotton jassids lay multiple eggs (14 to 60), which hatch in approximately one week. The nymphal stage lasts 5 to 16 days, and adults live for up to five weeks. The total lifecycle duration varies with temperature and humidity. For example, in India, generation time ranges from 15 to 46 days, allowing up to 11 generations per year, largely due to the continuous availability of host plants in warmer climates.

Host range

Cotton jassid has a fairly broad host range primarily within the families Malvaceae, Fabaceae, Asteraceae and Solanaceae. This includes cotton, okra, peanuts, soybeans, sunflowers, eggplant, potato, and many ornamental plants. When the pest invaded Florida it was first detected in high number infesting okra.

Cotton injury and symptoms

Nymphs and adults feed on the undersides of leaves, extracting sap with their piercing-sucking mouthparts and causing curling, yellowing, and bronzing of foliage—symptoms collectively referred to as “hopperburn.” Initial observations from Georgia indicate that jassid infestations and associated plant injury appear quickly after colonization and are most severe along field margins. Under heavy infestation, hopperburn symptoms extend throughout the field, leading to premature defoliation. Severe feeding stunts plant growth and can cause the premature drop of fruiting structures, resulting in yield and quality losses. In India, this pest is reported to cause up to 50% of yield losses in cotton and is known to be extremely difficult to control. This species of leafhopper is not confirmed to be a vector of any pathogens. While the full impact on yields in U.S. cotton is still uncertain, Extension experts and researchers across the Southeast where the insect has been found to infest cotton fields are actively investigating the impact of this pest as well as potential control options.

Hopperburn symptoms (Photo: Scott Graham, Auburn University)

Hopperburn and leaf reddening (Photo: Scott Graham, Auburn University)

Treatment decision and insecticide efficacy data

Based on the initial studies done in Alabama and Georgia, the recommended treatment threshold for cotton jassid is one to two nymphs per leaf. Scouting should focus on the undersides of mainstem leaves at the third, fourth, or fifth node from the top of the plant. The threshold applies when injury symptoms are observed, which helps confirm correct identification, as other leafhopper species do not cause similar symptoms. Populations and damage typically appear first along field edges before spreading inward. The ‘hopperburn’ symptoms could be confused with Verticillium wilt or severe potassium deficiency at first glance. It is important to look underside of leaves for presence of insects. Although insecticide efficacy evaluations are ongoing, Bidrin, Sivanto Prime, Sefina, and Carbine have shown promise in Georgia and Alabama. 

Authors: Suhas Vyavhare, David Kerns, Jose Santiago Gonzalez, and Patrick Porter; Texas A&M AgriLife Extension Service

Conchuela Stink Bug in Texas High Plains Cotton: Identification, Injury, and Management

As we enter the boll formation phase of the crop, one insect pest I have been picking up quite consistently is the Conchuela stink bug. It is a relatively large insect (~1/2 inch long) with a distinctive dark olive green to black coloration and a reddish margin around the body. Their populations develop on mesquite trees and various weedy hosts, and as the quality of these host plants declines, they migrate into grain crops and cotton.

These stink bugs are voracious feeders and can be found in multiple numbers on the same boll (picture below). Stink bugs in general prefer to feed on medium-sized bolls, approximately the size of a quarter-dollar coin. Feeding on young bolls (<10 days old) often leads to boll shedding, while in larger bolls, stink bug feeding results in the formation of dark spots on the exterior. These dark spots do not always correspond to internal damage, which is why the newer stink bug thresholds are based on internal boll damage.

Dynamic boll injury threshold for stink bugs

If stink bugs are being detected along the field margin, I would consider spraying a couple of swaths around the field edges. This proactive approach can help prevent or reduce the spread across the entire field. Also, this way, the entire-field insecticide application can be better timed during the most vulnerable stages of the crop (3rd to 6th week into bloom) in case population build-up and/or reinfestation continues. We have had many situations in past seasons where stink bug infestations went undetected until damage became obvious late in the season. The only way to avoid this is through regular crop monitoring and timely insecticide application when needed.

The most effective insecticide products for stink bugs are either pyrethroids (e.g. bifenthrin, lambda-cyhalothrin) or organophosphates (e.g. acephate, Bidrin). These chemistries are much harsher on beneficials compared to some of the softer products used for aphids and plant bug control. Therefore, I would avoid rushing into an entire-field application unless stink bug numbers or internal boll injury justify the treatment. Neonicotinoids, such as imidacloprid can offer some level of stink bug suppression, but products commonly used for cotton fleahopper, aphid, or plant bug control (e.g. Carbine, Sivanto, or Transform) will not provide stink bug control.

Conchuela stink bug adults on cotton boll

South Plains Cotton Pest Update: Product Choices for Fleahoppers and Aphids

With some of the early-planted cotton already in the second or third week of squaring, we are starting to pick up quite a few cotton fleahoppers and isolated colonies of cotton aphids across the region. One of the common questions I’ve been getting is about product choices for managing these pests.

For cotton aphids, I would keep a close eye before pulling the trigger. With all the rain we've had over the past few days, there’s a good chance it may wash off some of the aphids. So, I would let the weather and beneficial insects work their magic before making a treatment decision.

Most of the products recommended for cotton fleahopper also have some activity against cotton aphids. For instance, Transform WG, Centric 40WG, and Carbine 50WG—all commonly used for cotton fleahopper control—also offer decent efficacy on aphids. Of these three, Transform has the best activity on cotton aphids and is also very effective against fleahoppers.

Some of the cheaper options include acephate and Bidrin 8. Acephate is the least expensive but also the least rainfast, with shorter residual activity. Bidrin offers slightly better rainfastness and longer residual control on both cotton fleahoppers and aphids; however, it is much harsher on beneficial insects compared to Transform, Centric, or Carbine.

Adult cotton fleahopper (picture: Pat Porter)

Plant terminal infested with cotton aphids

Early-Season Beetle Activity in Cotton: Flea Beetles and Blapstinus Observations

I’ve consistently seen flea beetle damage on young cotton this season. Small feeding marks on the cotyledon leaves—especially in fields planted with untreated seed—are a sign of flea beetle activity. I’m mostly seeing pale-striped flea beetles. These insects have chewing mouthparts that scrape both the upper (more common) and lower surfaces of the leaves. At first, this doesn’t create visible holes, but as the damage ages, it turns into obvious holes in the cotyledons.

Flea beetle damage usually stays limited to cotyledon leaves and is mostly cosmetic. I haven’t seen much injury to seedlings in fields planted with neonicotinoid-treated seeds. Flea beetle infestations tend to be patchy and are more common along field borders, edges, and near drying weedy areas. Treatment is rarely needed and should only be considered if they begin to threaten stand establishment—which is very uncommon with flea beetles.

Striped flea beetle on cotyledon leaf

Another insect I’ve been spotting across several fields in the South Plains is the darkling beetle from the genus Blapstinus. These beetles are about ¼ inch long and black. Their larvae, known as false wireworms, feed on the underground parts of young seedlings. While only the larvae cause wireworm or false wireworm damage, the adult Blapstinus beetles are also known to feed on plants. You can often find several beetles clustered at the base of a single plant. Their chewing damage shows up on the stems, right at or just below the soil surface. If you see stand-threatening damage along with a heavy presence of these beetles, I recommend applying a foliar spray with a pyrethroid insecticide.

 

Early-Season Insect Activity in Seedling Cotton

The first insects I’ve seen feeding on seedling cotton this season are grasshoppers. I have spotted newly emerged grasshopper nymphs feeding on cotyledons and the first true leaves in localized areas of the South Plains. These young grasshoppers seem to be migrating in from nearby natural vegetation and weedy areas such as bar ditches.

If grasshopper numbers are high enough to threaten stand establishment, an insecticide treatment is recommended. Many areas—especially in the northern counties—will also need an over-the-top insecticide application for thrips. Products like acephate and dicrotophos (Bidrin) offer some control of grasshoppers, but their effects may not last long enough (especially if applied at the rates recommended for thrips) to prevent damage from new grasshoppers moving in. Therefore, it is important to keep a close eye on fields for continued grasshopper movement and be ready to make a second application if needed. Among all options, diamide insecticides offer the best grasshopper control, but they’re more expensive than pyrethroids or organophosphates. There are also products available with premixes of two or more insecticides, such as acephate + bifenthrin (e.g., Acenthrin), which provide control against both thrips and grasshoppers.

Besides grasshoppers, I’ve also seen chewing damage on cotyledon-stage cotton caused by Blapstinus darkling beetles and flea beetles in a few areas. This kind of insect feeding damage is more noticeable in fields planted without insecticide seed treatments. While minor cotyledon feeding usually isn’t a major concern, the damage becomes more serious when Blapstinus beetles chew on the stems—potentially knocking the seedlings loose.

Blapstinus beetles are the adult form of the false wireworm, a common pest across the South Plains. While there are no rescue treatments for the larvae (wireworms), adult beetle activity that threatens stand establishment may justify a pyrethroid spray.

Click here for the fact sheet on grasshoppers and their control