Dan Anco Clemson Update Peanut Notes No. 38 2021

— Written By
New 2ees
Velum (fluopyram) has this year received a 2ee adding Aspergillis Crown Rot suppression. Aspergillus Crow Rot can cause seedling death, usually after emergence, and typically becomes more severe when soils become hot and dry early in the season.
Microthiol Disperss (micronized sulfur) also received a 2ee this year for use in a tank mix with fungicides for improved leaf spot control. The rate on the 2ee is between 3 and 5 lb/A of the sulfur. Most of our work has been at the 5 lb/A rate looking at DMI fungicides (FRAC 3), though last year we also looked at the 3.75 lb/A rate. Both rates looked good, though the 5 lb/A rate did appear to have slightly more efficacy. We have some data showing improvements when combined with other FRAC group fungicides, though more work is being done this year to firm up these results.
Over the Top Fertilizer
How bad would it be if 120 lb/ac potash and 160 units N/ac, hypothetically, were applied over part of the top of where peanut was recently planted? While not an ideal situation, it isn’t the worst either. Biggest impact, in my opinion, would be on the pocketbook in terms of product cost of unnecessary application and caution regarding K levels. While K is not as mobile as N, excessive K in the pegging zone (only a few inches down) can interfere with Ca absorption during later pod fill. K is slightly more mobile in very sandy soils compared to soils with finer texture. Depending on exact soil test amounts, a cautionary approach would be to increase the normal land plaster rate by 500 lb (e.g., 2000 lb instead of 1500 lb, pending soil amounts, soil type, irrigation, etc.). I wouldn’t be inclined to overly worry regarding the N interfering with nodulation of developing taproots. Of the few studies that have been published similar to this where inoculant was added at planting, this amount of N did not cause major problems, though it will be interesting to keep an eye on it. Depending on how much rain we get, a lot can end up leaching away, though some remaining may help early season closing of the rows. Will need to wait until around 45 days after planting to verify any impact on nodulation.

Dan Anco

Extension Peanut Specialist and Assistant 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

Clemson Extension Peanuts

Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, gender identity, marital or family status and is an equal opportunity employer.