Asiatic Garden Beetle

Reports have come in this week of heavy asiatic garden beetle activity, in some cases in areas where it was not previous reported. Over the past several years, we have monitored adult beetle activity and the peak is consistently around the first week of June. There is however an extended period of emergence after that, in which beetles are still active.

Much of our early planted cotton has grown enough that it will outpace some asiatic garden beetle feeding at this stage. Some late planted cotton with only a few leaves may still be at risk. Carefully monitor any late planted fields, particularly fields with some history of asiatic garden beetle feeding and sandy fields. The best control measure is a spray of bifenthrin at the highest labeled rate. Although the beetles are active at night, research has not identified a difference in number of beetle cadavers when spraying during the day or at night.

Tarnished plant bug

Some cotton is beginning to square here in Suffolk, which means it is time to start scouting weekly for tarnished plant bugs. Protecting early squares is critical for limiting potential yield losses from this pest. That said, not every field will need an early treatment, and spraying too early can be a waste of input costs. The economic threshold from first squaring until the first or second week of bloom is;

More than 8 plant bugs/100 sweeps AND
less than 80% square retention

Try to avoid using strong broad spectrum insecticides (Acephate, Bidrin, Bifenthrin) until late in the season to prevent flaring up other pest issues. Pyrethroids (Bifenthrin, Warrior II) or mixes containing pyrethroids (Endigo, Brigadier) may also have limited efficacy for plant bugs due to insecticide resistance development. Once we reach the first week of bloom, sampling switches from the sweep net to a drop cloth. The threshold at this stage is 2-3 plant bugs per drop cloth sample.

Dominic Reisig at NC State University has a good visual guide to plant bug spray programs, depending on the total number of sprays needed, and when in the season they occur (https://cotton.ces.ncsu.edu/news/insecticide-recommendations-for-tarnished-plant-bug-2026/).

Cotton Jassid

Finally, a brief update on the invasive cotton jassid. The first confirmed reports of insect activity have come in from South Alabama, South Georgia, and Florida over the last couple weeks. Based on these being the first sightings in 2026, it is likely that these insects did not successfully survive this past winter in most of their 2025 spread area and will have to remigrate northward this year. These being the first sightings may be good news for us here in Virginia, but we will continue to monitor aggressively throughout this season. The current distribution can be found here (https://stop2scl.org/cotton/). This map will be updated in real time and will help us track the spread from the south in 2026.

Written By: Kemper Sutton and Tim Bryant

Reports of pea leaf weevil activity have come in from New Kent County and the Eastern Shore of Virginia. The pea leaf weevil (Sitona lineatus) is established in Virginia, but it is highly sporadic and rarely considered an economic pest in soybean. However, It has been found causing significant injury to seedling soybean plants this year. Many of the problem fields are soybeans planted into heavy residue from a legume cover crop, like vetch.

Adult weevils feed on seedling foliage, creating characteristic notching along leaf margins. Under heavy infestations, this feeding can lead to economically significant defoliation. Foliar insecticide applications should be considered when defoliation reaches approximately 40% at the seedling stage. Effective control options include pyrethroids such as beta-cyfluthrin, bifenthrin, cyfluthrin, and zeta-cypermethrin.

Larvae can also be a concern, as they develop in the soil and feed on root nodules, potentially reducing nitrogen fixation in host plants. However, currently, there have been no confirmed reports of larval injury in soybean fields in our region.

Fields planted without an insecticide seed treatment may be at greater risk, as seed treatments can provide early protection against both foliar feeding and belowground injury. These fields should be prioritized for scouting.

We are beginning to see thrips numbers and injury increase in trials on the research station in Suffolk. Many folks are making decisions this week about whether or not a foliar application is needed, and if so, what to spray.

The first thing to consider in cotton is the growth stage. You are most likely to get an economic return on a foliar application made at the early first true leaf stage. Applications made beyond this stage usually have diminishing return on that investment. In many of our trials planted in late may, we have progressed to the second true leaf stage, and third true leaf in some cases.

Last year, we found tobacco thrips in Virginia with reduced susceptibility to acephate (~75-80% mortality). This year we are continuing to monitor using lab assays and field trials. Results of lab screenings are still to come, but in our earliest field tests on station, acephate (at 8 oz/ac) has provided an acceptable level of control. This is one location and one planting date. Milage will vary by location, planting date, and field conditions. If you decide to make a foliar application of acephate, it will be important to carefully monitor after the fact to ensure an acceptable level of control. The alternative option which provides excellent control is Hemi SC (2.5 – 3.0 oz/ac). This product needs to be applied with a non-ionic surfactant or with an herbicide that already has a surfactant to provide good control.

In 2025, the percentage of western flower thrips in the population was high (70%-80% in many fields). This year, we have seen the opposite so far with about 70% tobacco thrips in our tests on station. Western flower thrips have always been more difficult to control with acephate, so a lower percentage of this species makes acpehate a more viable option. Again, the species composition can vary by location and field conditions.

As always, please contact me with any questions you may have.

Cell: 757-621-8804, Email: btim2@vt.edu

Syngenta Crop Protection recently announced EPA’s approval of their registration of five new insecticide products containing the active ingredient PLINAZOLIN technology (isocycloseram), which is a unique active ingredient that belongs to IRAC Group 30, offering broad-spectrum insect pest management.

https://www.syngenta-us.com/crop-protection/technology/plinazolin-technology/

Zivalgo^™: a foliar-applied insecticide for pome and stone fruit, citrus, potatoes and tree nuts that goes the distance in the race against codling moth, Colorado potato beetle and more with marathon-caliber residual control

Equento^®: this insecticide seed treatment for cereals and pulses offers a flexible and compatible option to terminate wireworms and suppress other below-ground pests, ultimately improving plant stand and helping growers’ bottom line
 

Opello^™: this soil-applied insecticide provides revolutionary control of corn rootworm, consistently helping corn yield up to 27 bu/A more than untreated¹, while its highly tank-mix compatible formulation allows growers to leave equipment clogs and slowdowns in the past
 

Vertento^®: a foliar-applied insecticide for cotton, onion, peanuts and soybeans that lands the knockout punch on tough-to-manage insect pests like plant bugs/lygus, stink bugs and mites, and offers champion-level residual control
 

Incipio^™: a foliar-applied insecticide for vegetables that’s tough on pests like diamondback moth and thrips but easy on growers, helping protect their time and peace of mind with long-lasting and reliable control
 

My lab has field-tested these insecticides against many pest groups on vegetables, potatoes, and other crops over the past several years. Plinazolin insecticide offers a wide pest spectrum including some hard-to manage pests such as: thrips, mites, lepidopteran larvae like diamondback moth and beet armyworm, Colorado potato beetle, alfalfa weevil etc. Because its mode of action is much different than other insecticides, it offers an excellent rotational tool for insecticide resistance management.

While presenting at a community garden meeting with growers and gardeners in Boydton, VA this morning (Sept 10), one of them talked about a pest that was creating holes in her sour gherkin cucumbers. I checked it out and it was pickleworm (see photos). Location was Clarksville, VA. This is not good news for our large pumpkin industry in Virginia. This means that at least some of these tropical moths have mead their way from the southern U.S. on storm fronts and are depositing eggs on blossoms of cucurbit host plants like cucumbers, squash, and pumpkins.

Larvae bore into fruit where they can cause the fruit to rot in addition to reducing marketability of the fruit. Growers should inspect their fruit and blossoms regularly until harvest. If pickleworm is found, there are many effective insecticides to control it, but the most affordable would probably be a pyrethroid.

Like every year, I get a lot of questions on late leaf spot fungicides the closer we get to digging. Since it’s near the end of the season, regardless if you’ve been on a rigorous, effective leaf spot program you’re going to see some leaf spot. I’ve heard some growers are having severe leaf spot and some significant defoliation. Below I’ll cover some points regarding late leaf spot management as we approach digging.

1. Leaf spot has a greater affect on yield the earlier it occurs.  If the onset of disease begins near harvest we often don’t observe much loss.  I’d be more concerned about yield loss in fields where leaf spot was significantly spreading in early to mid-August compared to just seeing it get worse since labor day weekend.  However, if you see up to 40% or more defoliation, a fungicide application at that point isn’t going to help and you may consider digging early to help preserve yield.
2. The cooler it gets leaf spot takes longer to spread.  Cooler weather coupled with the extremely dry weather we’re experiencing really slows disease development.  The big increases in leaf spot you’re seeing now are the result of infections that took place 2-3 weeks ago or more.  That would mean the fungicide applications you made (or not) early to mid-August are impacting what you’re seeing now more than sprays you applied within the past 2 weeks.  Applying a fungicide now won’t have a major impact on leaf spot or yield.
3. Just because I just said spraying leaf spot now won’t have a big effect on yield doesn’t mean spraying for leaf spot is a terrible idea right now.  A lot of that depends on how close you are to digging based on peanut maturity.  If you’re over 2 weeks away from digging I can see where a fungicide application may help leaves stay on longer and prevent yield loss compared to peanuts that are within 2-weeks of digging.  Everyone’s maturity situation is different, and it can vary from field to field.  The situation is very different between dryland and irrigated peanuts.  In talking to Jacob Forehand in Virginia and David Jordan in NC this morning, according to pod blasting results, peanuts are not maturing very quickly due to cool, dry conditions and peanuts may be mature a little later than “normal”.  Plus, although the forecast isn’t calling for much rain, if it becomes warmer and we get some unexpected rain that can change things so far as maturity and diseases are concerned.  Lots to consider…
4. If you’re going to use a fungicide this late, make sure it’s a fungicide that’s going to be effective (kinda intuitive I know).  I hear about a lot of people making fungicide recommendations that are questionable.  If you ask me about a fungicide to use right now I’m going to tell you to use Provost Silver or chlorothalonil (Bravo, Echo, Equus etc) with or without micronized sulfur.  Why those?  They are the only fungicides that I am confident in providing some control.  The efficacy and curative activity of Provost Silver is well established, chlorothalonil works as well as it did when it was first used back in the 70’s because it has multiple modes of action and carries practically no risk of resistance development, and micronized sulfur has been shown by several researchers in several states to enhance the efficacy of leaf spot applications when mixed with an effective fungicide.  Each product has some downsides which may be a cause for pause. 
5. We use FRAC Group 3 fungicides in almost every application we make on peanuts, and the actives in Provost Silver are both groups 3’s.  Provost Silver is probably the most used FRAC Group 3 fungicide.  The more we use the same MOA (mode of action) over and over again we put more pressure on them for resistance development.  Couple that with spraying when higher inoculum levels are present during the late season adds more to the resistance risk. 
6. Chlorothalonil has been shown to increase the risk of spider mite development, and to a lesser degree it can enhance the development of Sclerotinia blight.  As dry as it is I can see growers being resistant to use chlorothalonil because of spider mites.  But since sulfur has some activity against spider mites, I’ve been suggesting tank-mixing it with chlorothalonil to provide some control of spider mites.  Spider mites are favored by hot, dry conditions.  We have the “dry” but don’t have the “hot” right now and looking forward.  I’m not saying there’s no risk of spider mite infestations right now, but conditions are less favorable for them to occur.
7. The main issue with sulfur are problems with mixing and it’s potential to leave residues in spraying equipment that can cause clogging.  I recommend trying different formulations of micronized sulfur.  The one’s I’m familiar with are Microthiol Disperss® (dry), Kolla® (liquid), and Suffa® (liquid).  I keep using the word “micronized” for a reason.  That is that all the positive efficacy data I talked about earlier was with micronized formulations only.  Non-micronized sulfur does not show the same positive effects on leaf spot control.

Corn earworm larvae have been found well in excess of economic thresholds in several counties throughout Virginia the past two weeks. In Prince George, we sampled a field with 50+ larvae per 15 sweeps (see below photo). There are a few key things to remember for managing corn earworm in soybeans.

1. It pays to scout. Use the economic threshold.
   For corn earworm in soybeans, we have what’s called a “dynamic threshold”. The benefit of using a dynamic threshold is that it shifts with commodity prices, production practices, and the cost of control and you can be certain that you will get economic return on a spray under current conditions. You can find the calculator here. At an estimated soybean price of $10/bu, and $15 cost of control using a sweep net to sample 15 inch soybean rows you get an economic threhsold of 2.2 larvae per 15 sweeps.
   
   We have expanded our corn earworm moth monitoring in 2025. While these traps do not indicate the need to spray alone, they can guide your scouting efforts and help make decisions. The monitoring tool is updated in real time and can be found here.
2. Select the right insecticide
   Pyrethroids alone will have limited efficacy for corn earworm, particularly for large larvae. Our most recent efficacy data can be found in the figure below. These numbers are total number of corn earworm larvae per 15 sweeps at 2 days post application. If targeting stink bugs as well as corn earworm a product containing both a pyrethroid and a diamide (I.e. Besiege or Elevest) would be a good option. If you are also reaching defoliation thresholds (15% during reproductive stages) and have mostly soybean loopers, Besiege has offered limited control for soybean loopers in recent years. Intrepid Edge or Steward are good options to manage both corn earworm and soybean loopers.

As always, please contact me if you have any questions or concerns. Tim Bryant (btim2@vt.edu).

With as hot as it’s been in July, it’s hard to imagine Sclerotinia blight showing up in peanuts. I have been searching for it in my trials but haven’t seen it yet. However, highs in the low 80s and lows around 70 today through next week means conditions will be favorable for disease development. Plus, adequate soil moisture is present due to recent rains and peanut canopies are dense enough to favor Sclerotinia blight. I recommend monitoring the Virginia Sclerotinia Blight Advisory on the Peanut Cotton InfoNet to check the risk of this disease in your area and scout for disease, especially in fields with a history of Sclerotinia blight. Access the Peanut Cotton InfoNet using this link https://infonet.ext.vt.edu/. You can also call the VA Peanut Hotline at 1-800-795-0700 for up-to-date disease advisories.

At this point in the season I recommend fungicides Omega or Vantana tank-mixed with a leaf spot fungicide if you haven’t already applied Miravis + Elatus. I hesitate to recommend the first application of Miravis + Elatus this late in the season due to concerns about late leaf spot escapes as these products have no curative activity against leaf spot. You’re okay if it’s the second application. Fontelis at 1.5 pt/acre can provide some disease suppression if sprayed preventively.

Please contact me if you have questions.

David Langston. (757) 870-0498 cell email: dblangston@vt.edu