Published on Monday, July 13, 2015
Following a month of rain, cloudy days, and moderate temperatures, disease continues to be a threat this growing season. With spores set up for perfect growing conditions, pressures from northern corn leaf blight (NCLB) and gray leaf spot (GLS) are leaving farmers with cause for concern.
Check out Intern Christy Kettler's updates below!
Northern corn leaf blight becoming a cause for concern
while brace roots struggle to establish in soil.
Christy Kettler | Sales Intern | Central Indiana
July 6 – July 10, 2015
According to the Purdue University’s Extension program, the time to worry about northern corn leaf blight affecting yield potential is when the lesions have worked their way up to the ear-level leaves before pollination. There is a possibility of hybrid corn yields falling by 30 percent if NCLB takes away photosynthetic potential at or right before tasseling.
Aside from the loss of leaf area and photosynthetic action, NCLB can play a role in stalk rot as well. Northern corn leaf blight should be monitored in relation to the growth and reproductive stages of the corn. Management, through the use of fungicide, may be needed after pollination.
Fungicides have the capacity to slow the spread of NCLB, but cannot kill all of the spores and stop the disease in its tracks. Spraying can add an additional two weeks of growing to the plant, but will not completely control the lesions ability to grow and spread up the plant.
Northern Corn Leaf Blight
Gray leaf spot and holcus are still present and growing in Indiana corn as well. The holcus spots should be monitored, but usually do not have potential to affect yield or diminish plant health. Gray leaf spot (GLS) has become fairly heavy in the lower canopy of many corn fields in the state. The wet conditions and lack of sunshine have created a perfect breeding ground for the disease. Historically, GLS has not proved to be as dangerous as NCLB, but it does limit the photosynthetic activity for corn.
Grey Leaf Spot
Due to over saturated soils that have dried out, brace roots are unable to penetrate the soil. Areas that have dried out have left a very hard top layer which is too tough for most brace roots to establish into. The concern with this issue is the ability of the plant to remain standing once the weight of an ear is present.
Our findings show that corn borers are still feeding on non-GMO crops. These insects can damage plants and move on to the next ones down a row, leaving behind damaged tassels that are wrapped in the whorl. Controlling the spread of these borers is a very timely task. Catching the egg masses is key and spraying an insecticide before they have a chance to burrow down into the stalks.
The traps throughout north central Indiana have shown the next wave of European corn borer moth flight action. I have found 11 moths this week and expect those to be laying egg masses soon for the next generation to attack the fields. Visit Purdue Entomology and Agronomy updates for more information.
Check back next week for more findings!
If you have any questions about these findings or would like more information, please reach out to myself or your seed advisor.
Author: Denny Cobb
Categories: Agronomy, N Indiana, Michigan
Tags: Beck's Blog, AgTalk, Agronomy, Agronomy Update, agronomist, Beck's Agronomist, michigan agronomy, indiana agronomy, Denny Cobb Agronomy, European corn borer, Gray leaf spot, Northern corn leaf blight