Extension Field Reports: Goss's Wilt and Sulfur Deficiency in Corn; Hail Photos - UNL CW, June
June 28, 2013
Figure 1. Goss's wilt of corn
Figure 2. Paired comparison archive/-/asset_publisher/VHeSpfv0Agju/content/research design using buffer rows.
Figure 3. Harvest plan for paired comparison archive/-/asset_publisher/VHeSpfv0Agju/content/research plots.
Jennifer Rees, Extension Educator in Clay County: Goss’s bacterial wilt (Figure 1) was found this week in corn damaged from Memorial Day storms in Clay County. I’ve also received pictures that appeared to be Goss’s wilt from crop consultants in other areas of the state. Goss’s wilt lesions have a wavy edge, a varnished look when wet, and characteristic black “freckles” within and particularly along the lesion edges. We are seeing some plant death due to the systemic version of Goss’ wilt.
This can be seen by taking a cross-section of the stem and looking for orange discoloration in the vascular bundles. Because this is a bacterial disease, fungicides are not effective in controlling Goss’s wilt. If you try one of the other kinds of products on the market, consider conducting an on-farm archive/-/asset_publisher/VHeSpfv0Agju/content/research comparison. Spraying the product in a paired comparison treatment design (Figure 2) will provide information on whether the product made a difference in your field.
To conduct this archive/-/asset_publisher/VHeSpfv0Agju/content/research on your farm,
- Spray a pass or round with the product (depending on sprayer size) to ensure you can harvest two passes from the center of the treated area.
- Skip the same amount of distance as you previously sprayed.
- Repeat steps 1-2 at least three more times.
Mark a few plants in each plot and take photos throughout the growing season to determine whether the disease progresses. You also may want to keep track of the percent of plants affected in each treated and untreated area throughout the season, as well as the percent stalk rot and harvest population in each area.
At harvest be sure to make two passes from the center of each treated and untreated area, then compare the weights as shown in Figure 3.
On-farm Research. For help in designing this on-farm archive/-/asset_publisher/VHeSpfv0Agju/content/research trial or to share results, contact Jenny Rees at firstname.lastname@example.org or (402) 762-3644. UNL on-farm archive/-/asset_publisher/VHeSpfv0Agju/content/research information is available in the Farm Research section of CropWatch.
Details. For more information on Goss’s wilt see this NebGuide, Goss's Bacterial Wilt and Leaf Blight of Corn (G1675).
- Diagnosis. To submit a sample of suspected Goss's wilt for diagnosis, send it to UNL’s Plant and Pest Diagnostic Clinic.
Follow crop production in south central Nebraska on Rees' blog at JenREESources's Extension Blog.
|Figure 4 (left). In northeast Nebraska soil with 10 ppm Mehlich III P, with 24-80-0 -20S spring-applied, N balanced to 180 lb N/acre.||Figure 5. A northeast Nebraska corn field where the soil test indicated 18 ppm Mehlich III P, with 24-80-0-0S spring-applied and N balanced to 180 lb N/acre.|
Figure 6. Corn leaf showing symptoms of sulfur deficiency.
Charles Shapiro, Extension Soils Specialist at the Haskell Ag Lab near Concord: With cool, wet conditions this spring, nutrient uptake in some Nebraska corn fields was slow. Striped, yellow leaves indicated a sulfur-deficiency in some cases. With warmer temperatures this week, the condition is improving and a sulfur application may not be needed on fine textured soils. An article in this week's South Dakota State University newletter, iGrow, also includes a report on this field symptom. It notes that in most years "soils would warm and microbial activity (mineralization) would release sulfur by the time corn needs it ...."
Figures 7-8. Hail damage in dryland corn (left) and wheat (right) in northwest Banner County from a thunderstorm that rolled through June 22. (Photos by Gary Stone)