Comments From Dan Anco Clemson Peanut Notes No. 164 2024

Beet armyworm 

Foliage feeding caterpillar damage was seen in a field in Hampton County. Worms were no longer present. Several beet armyworm moths could be seen in the field, suggesting their larvae were likely responsible for the feeding. Since no worms were observed, a spray at this stage when worms are not present would not be recommended. Where actively feeding armyworms are present (8+/ft lapped, 4+/ft unlapped/stressed), a specific worm insecticide like chlorantraniliprole (Prevathon/Coragen/Vantacor/Shenzi), or Intrepid Edge would be an effective option to avoid killing beneficials and possibly flaring spider mites. Feeding here was readily 50% defoliation in places, and while this will likely affect yield some, good growing conditions to finish out the rest of the growing season will help the crop to recover and produce pods.


James Thomas has observed a few velvetbean caterpillars near Estill and yellowstriped armyworms in part of a field near Denmark. Leafhoppers and their feeding have also been observed.


White Mold Fungicide w/ or w/o Bravo

Certain fungicides with activity against white mold are often applied with Bravo to improve overall control of leaf spot. In some cases where prolonged field history of peanut production has resulted in the build up of heavy white mold pressure, we may be looking for ways to improve our overall white mold control while not abandoning effective leaf spot control. The presence of surfactants in chlorothalonil products such as Bravo WS help it to adhere to the leaf. It may be possible that applying a white mold product with Bravo could lessen the amount of it that reaches the soil, although I do not have data to add alongside this. That being said, considering leaving Bravo out of a tank mix should be approached on an individual product basis. Something like Elatus overall has enough leaf spot activity where it should provide adequate protection when applied alone in an application when alternated and applied in an overall program. Something like Convoy I would still like to have Bravo (or another product such as Alto/Domark/Topguard) go out with it since it alone would still need a product to provide leaf spot management. We have many good options available for disease control, including a number with activity against both soil and foliar diseases (page 54 in the production guide includes many of these, including but not limited to Lucento, Provost Silver, Umbra...). If there is an effect of Bravo reducing the amount of coapplied soil fungicide being able to move down into the soil profile to a notable degree, this would be more relevant when looking against applications that receive rainfall or irrigation in a timely manner to aid in wash-in. Work has shown the benefit of washing in, while certainly helpful and more so helpful when immediately occurring or soon after application, to decrease rapidly after two or more days. Conditions of the year thus far have overall been favorable to development of white mold; however, in many fields in SC, leaf spot can be more of a concern based on field history and rotation, etc.


Fungicides with Curative Activity

Should rains delay field access so as to result in a spray becoming several days late in a field where leaf spot control is the primary concern, Provost Silver would be a good product to use to provide some curative + protectant activity. Applying Provost with micronized sulfur would be an added boost, but folks have noted the additional mixing logistics to be less favorable to conduct. Priaxor or Revytek are additional options.


Herbicide Injury

The second and third set of pictures was from a field where part of it showed a readily observable concentration of necrotic and chlorotic plants. A range of symptoms were present that included yellow bleaching of leaves across the entire leaf and along leaflet edges, sometimes in smaller splotches. Rolled/cupping leaves could also be observed in areas. The symptoms were more prevalent where the sprayer began in the field. The sprayer had been used for dicamba + roundup the day prior. The injury suggests incomplete cleanout. Leaves bleached by roundup can turn white with time. Pictures courtesy of Kyle Smith.


Upcoming Events:

Corn/Soybean Field Day at Edisto REC, July 25

Cotton/Soybean/Peanut Scouting Workshop in St. Matthews, July 29 (flyer attached)

Peanut/Cotton Field Day at Edisto REC, September 5


Peanut images 7-24-24

Scouting School 07292024

Dan Anco

Extension Peanut Specialist and Associate Professor

Department of Plant and Environmental Sciences

Clemson University – Edisto Research and Education Center

64 Research Road

Blackville, SC 29817

630-207-4926 cell

danco@clemson.edu