Agronomy Talk

AGRONOMY TALK: FOLIAR FUNGICIDES IN CORN

Published on Wednesday, November 25, 2020

 

Data from Beck’s Practical Farm Research (PFR)® studies show that there are several multiple mode of action (MOA) fungicides, that when applied at VT/R1, have provided a positive return on investment (ROI). When applying a fungicide, farmers not only expect to protect their crop from yield-robbing leaf diseases but also to improve late-season standability by reducing stalk rot infection and maximizing harvestability.

To learn more about leaf diseases that can threaten to reduce corn yield, follow this link (Corn Foliar Diseases). To learn more about stalk rots, follow this link (Stalk Rot in Corn). 

One of the benefits from a strobilurin (QoI)-containing fungicides, such as those containing the active ingredients azoxystrobin, fluoxastrobin, picoxystrobin, pyraclostrobin, or trifloxystrobin, is the reduction of ethylene production within the crop canopy. Ethylene is a naturally-produced gaseous plant hormone. In a healthy corn crop, ethylene gas is produced within the crop canopy once pollination is complete and kernels begin to develop. This initiates the processes leading to plant senescence. Common signs of plant senescence in corn include the transition of green leaf tissue to yellow/ tan/brown color, leaf drop, tassel and silk drop, etc. If a strobilurin-containing fungicide is applied near pollination, ethylene production is significantly reduced, thus promoting a “greening” effect. This is usually beneficial for grain yield since it will allow the maximum amount of carbohydrates stored in the leaves and stalks to enter the developing kernels. A strobilurin-containing fungicide application near VT/R1 not only protects yield by helping control diseases and delaying senescence, but it can also help manage environmental stresses. When plants are subjected to a variety of abiotic (temperature and drought) and biotic (pathogen and insect) stresses, they will naturally produce more ethylene to regulate developmental processes within the plant. Although results have been somewhat inconsistent, there is evidence that improved nitrogen utilization may also be a benefit where fungicides have been applied. Lastly, if corn plants are kept healthier longer into the growing season, there is less ability for stalk rot pathogens to infect and cause stalk quality and harvestability issues. 

Previous research has shown that a strobilurin-containing fungicide applied in corn at VT/R1 can cause increased grain moisture at harvest. This is likely due to delayed senescence and the aforementioned “greening” effect. The difference in grain moisture between fungicide-treated and untreated can depend on many variables; however, one of the most significant variables is the harvest moisture level. In general, if corn grain moisture at harvest is below 20%, there is typically about 0.5 to 1% higher grain moisture where a strobilurin-containing fungicide was applied. As harvest grain moisture increases above 20%, there is usually a larger difference in moisture between treated and untreated.

Carboxamide (SDHI)-containing fungicides such as those containing the active ingredient benzovindiflupyr, bixafen, fluxapyroxad, or pydiflumetofen, are being evaluated to determine if there are beneficial physiological responses like those found with strobilurin-containing fungicides described above. Initial results suggest this class of fungicides also has plant health and “greening” effect benefits. 

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Author: Chad Kalaher

Categories: Agronomy, Agronomy Talk

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Chad Kalaher
Chad Kalaher>

Chad Kalaher

Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as researc

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Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as research agronomist, district, and regional sales manager.

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