Crop Production
The Alabama Crops Insect Report contains some the latest information on insect activity in the state’s major row crops. These updates come from members of the Alabama Cooperative Extension System agronomic crops team. For more information on row crops in Alabama, listen to the Alabama Crops Report Podcast and subscribe to the Alabama Crops Report Newsletter.
Soybeans
March 15, 2023 – Points to Consider for 2023 Soybean Insect Management
by Scott Graham
Cover Crops
Both the cover crop(s) used and burndown timing can impact early season pest pressure. Consider using an insecticide seed treatment (IST) if the cover crops are terminated at plant, regardless of the cover-crop mixture. If a legume species (e.g., crimson clover) was used, ISTs will likely be needed if cover crops are not terminated at least 4 weeks prior to planting. If no legume cover crops were planted, an IST may be needed if burndown is done 2 to 4 weeks prior to planting.
Planting Dates
Planting date may play a role in pest pressure and infestation throughout the season. In general, early-planted soybeans are considered to be at a lower risk of stink bug and defoliator infestations than late-planted soybeans are.
Defoliators
There are three main defoliating caterpillars that infest Alabama soybeans: green cloverworm (GCW), velvetbean caterpillar (VBC), and soybean looper (SBL). While GCWs rarely cause economic damage, VBCs and SBLs can completely defoliate a field in 10 to 14 days. Keep an eye out for VBCs and SBLs from mid-August through September, as long as soybeans are susceptible to defoliation (R6.5).
Stink Bugs
Stink bugs are commonly the most yield-limiting insect pest of soybeans in Alabama. Populations tend to build as pods develop, around the R5 to 6 stages. Stink bugs can be managed with most labelled pyrethroids. Don’t let them rob yield and quality. Scout and treat stink bugs as needed in the R5 to 6 window.
Redbanded Stink Bug
Speaking of stink bugs, the redbanded stink bug (RBSB) is the most damaging pest of soybeans in the South. This species is not native to the Unites States and does not survive cold weather well. Hopefully, the hard freeze experienced near Christmas was long and cold enough to kill them. If redbanded stink bugs are found, two-way tank-mixtures of acephate, pyrethroids, or neonicotinoids are needed for control. In flowering soybeans, consider making an application of a pyrethroid to knock down migrating adults and reduce egg lay. RBSBs tend to be worse in early- and late-planted beans, which are the first and last game in town.
Scouting and Monitoring
In 2022, the most targeted pest of soybeans in the US was automatic insecticides, according to the soybean insect losses report. In order to maximize the return on investment of an application, there needs to be an economic infestation of pets in the field. Scouting and monitoring is the best way to determine what is in the field and at what levels.
Cotton
March 10, 2023 – Points to Consider for 2023 Cotton Insect Management
by Ron Smith and Scott Graham
Grasshoppers
Grasshoppers tend to be worse in lighter, well-drained soils and following dry winters in reduced tillage fields. Immatures begin hatching out in late March and continue until June. Stand loss occurs when grasshoppers feed on the mainstem of emerging seedlings. Preventative insecticide applications are a judgement call based on the risk a grower is willing to take.
Thrips
Getting cotton seedlings off to a good start is important for maximizing yields. Remember that what we see above ground is a good indication of the below ground root system. Use the Thrips Infestation Predictor Model to help gauge which planting dates are at the highest risk of infestation.
Tarnished Plant Bugs
Migrating adults in June may or may not reduce pinhead square retention below 80-85%. However, they are depositing 100-150 eggs per female that will hatch out in July to present post bloom control needs. Don’t give them a head start. When treating plant bugs after the second to third week of bloom, use tank-mixtures or chemistry that will also control stink bugs.
Aphids
Aphids always crash from natural disease, sometimes a little later than desired. If controls are warranted, use a chemistry that will also suppress plant bugs.
Bollworms
Damaging levels of bollworms have not been an issue since 2017 but still keep an eye out between July 20 and August 10 if planting 2-gene cotton. Bollworm control with foliar insecticides is better when applied to small worms.
Spider Mites
Mites are present in most fields season long. They reproduce and spread faster during hot, dry periods. Do not make treatments when rainfall is abundant or in the forecast for the next few days.
Stink Bugs
Stink bugs are often the most damaging pest of Alabama cotton. One reason is time, stink bugs damage bolls in the mid-to-late season, leaving little time for the plant to compensate. The most critical period for stink bug control is between the third and sixth weeks of bloom when most of our yield is being set.
Be Informed
Cotton insect management is different from all other aspects of row crop production. The situation changes from week to week and sometimes field to field. To stay up to date on the situation in Alabama, subscribe to the Pest Patrol Hotline, Alabama Crops Report and Cotton Shorts Newsletters, and the Alabama Crops Insect Report.
Peanuts
March 1, 2023 – Planning for Peanut IPM in 2023
by Scott Graham
Moving into the 2023 peanut production season, producers’ goal should be to maximize the economics of peanut insect management. This can be achieved by scouting and monitoring insect pests and making sound IPM decisions throughout the season.
Thrips and Tomato Spotted Wilt Virus
Thrips and the transmission of tomato spotted wilt virus (TSWV) are the most consistent insect pest of peanuts in Alabama. Surveys conducted by the Alabama Extension peanut team show that TSWV incidence varied across commercial fields in 2022, with a state average of 6.5%. Research from colleagues at the University of Georgia suggests that 1% of TSWV incidence equates to approximately 19 lb. of peanuts. Thus, it can be estimated that TSWV caused Alabama peanut production a reduction of approximately 124 lb. in 2022.
There are a few things that can be done to reduce (not prevent) the risk of TSWV incidence in 2023. Planting date, varietal selection, and the use of the at-plant insecticide, phorate (Thimet), are all factors to consider and can be planned before the crop is planted. In a graduate-student trial conducted at the Wiregrass Research and Extension Center in 2022, Claire Cooke found that May and early-June planting dates had significantly less TSWV and higher yields than April planting dates did. Additionally, she found that plots treated with Thimet had higher yields than untreated plots. While variety (GA 12Y, GA 06G, and AU 17) selection played a role in virus incidence, those trends did not follow in yield. In other words, when planning for thrips and TSWV management in 2023, plan to plant the crop in May or early June, use Thimet at plant, and pick the highest yielding variety available to maximize profits.
Sporadic Pests
Many other insect pests found in Alabama peanut fields are sporadic or induced for many production areas. Spider mites are a threat in hot, dry periods and may flare following applications of broad-spectrum insecticides. There are currently two options for spider mites in peanuts, Comite II and Portal. One item on spider mites that is important to keep in mind is burndown preplant. Historically, spider mites were considered a border pest, as infestations often built around field edges and worked their way in and across the field. More recently, infestations may be observed starting anywhere across the field. This is likely related to the shift to reduced tillage and adoption of cover crops. Eliminating the green bridge of cover crops or winter weeds at least 2 weeks, but ideally 4 weeks, prior to planting will reduce the likelihood of spider mite populations building across the field. That is not to say it guarantees no spider mites, but it helps to reduce the chances.
Other sporadic pests–like peanut burrower bugs (PBB) and corn rootworms–present major potential challenges in 2023. The loss of chlorpyrifos (Lorsban) leaves producers with no reliable, effective options for this year. Since PBBs are almost exclusively a problem in reduced-tillage fields and in hot, dry conditions, producers do have the option of tilling prior to planting in fields with a historic PBB issues. For corn rootworms, heavier soils, irrigated fields, and fields adjacent to corn tend to be at a higher risk.
More Information
Insect management is different from all other aspects of crop production. The situation changes from week to week and field to field across the state. Proper scouting and monitoring techniques and insecticide selection are critical for economic production. To stay up to date on the peanut insect situation, check out the Alabama Insects Blog, Pest Patrol Hotline, and the Alabama Crops Report newsletter and podcast. Don’t hesitate to call or text (662) 809-3368 or send an email to scottg@auburn.edu for help.
Corn
No updates at this time.
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