Agronomy eUpdate July 28th, 2022

Issue 917

Biomass production and nutrient uptake of drought-damaged corn

Many farmers across Kansas must make a decision on how to get the most from their drought-damaged corn this year. A number of factors should be considered when assigning a value to drought-damaged corn. Nutrient removal from the field is one key aspect since biomass can export significant amounts of nutrients.

corn forage drought drought stress nutrient availability 

Nitrate toxicity in drought-stressed corn and sorghum

Drought-stressed crops such as corn and sorghum tend to accumulate high nitrate levels in the lower leaves and stalk of the plant. Nitrates accumulate when stresses reduce crop yields. Farmers should test their drought-stricken forage prior to harvest. High levels of nitrate can be toxic when fed to livestock.

sorghum corn drought stress nitrate toxicity 

Wheat streak mosaic virus: Problematic in central Kansas for the second year in a row

For the second year in a row, wheat streak mosaic virus was problematic in wheat in the central corridor of Kansas. One of the best preventative measures for wheat streak is the control of volunteer wheat early and often after harvest. Volunteer wheat should be terminated at least two weeks prior to planting.

wheat volunteer wheat wheat streak mosaic wheat curl mite 

Critical timing in Kansas: High temperatures and corn development

The July heatwave came at a particularly critical period for the Kansas corn crop this year. Heat stress will have more of an impact on corn during the reproductive stage of growth when combined with drought stress. Stress conditions were very severe in parts of central, south central, and southeast Kansas.

corn drought stress heat stress corn development pollination 

First report of southern rust in Kansas

Southern rust has been detected in northeast Kansas, making this the first report of 2022. The severity will be dependent on the weather. Southern rust likes 90-degree days, warm nights, and high humidity. Get answers to the most questions about southern rust in this article from K-State plant pathologist, Dr. Rodrigo Borba Onofre.

corn southern rust foliar diseases 

Large numbers of fall armyworm in Texas, moths appearing in southern Kansas

In late June, large numbers of fall armyworms were being documented in Texas. Fall armyworm adults were detected in southwest Kansas during the first week of July, with numbers on the rise. At-risk crops should be scouted regularly for the remainder of the growing season. Recommended treatment thresholds and labeled products are discussed in this article.

insects fall armyworms 

Be on the lookout for the soybean gall midge

Soybean growers in the northern parts of Kansas need to be aware of a potential new pest, the Soybean Gall Midge. While not found in KS yet, it has been detected in southern Nebraska. Yield losses from this insect are due to plant death and lodging. Learn how to identify this emerging soybean pest and how to report any possible sightings.

soybeans insects soybean gall midge 

EPA seeking public comment on atrazine re-registration review decision

The Environmental Protection Agency has requested public comment on the proposed additional mitigations to reduce potential exposure and risk to aquatic communities from atrazine via runoff from agricultural uses in field corn, sweet corn, sorghum, and sugarcane. Details on how to submit comments are outlined in this article.

label requirements herbicide EPA atrazine 

K-State North Central Experiment Field Fall Field Day, August 16

Join K-State Extension specialists at the 2022 North Central Experiment Field Fall Field Day on August 16. The is a free event and no pre-registration is needed. Topics include improving N use efficiency, foliar and in-furrow corn fungicide update, and using cover crops for weed management.

Fall Field Day