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Bluestem Breezes

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Potential Disease Problems with Standing Crops

Many fields of corn, grain sorghum, and soybeans in Kansas that would have normally been harvested by now are still standing because of wet weather and slow dry-down. If these conditions persist and the crops have to remain in the field longer into October and November, will they develop molds or other disease problems? KSU Extension Plant Pathologist Doug Jardine updates us this week on risks to our crops still remaining in the fields:

CORN: If corn has ear mold in it now, the problem may worsen as long as the crop remains in the field. If there is no ear mold currently present, it will not develop on standing corn now, even under wet conditions. Ear molds can infect corn through the silks during the pollination period, or following injury from insects or hail. You can head out now and check about 100 ears throughout a field to determine the level ear mold is present. Be sure to check any low spots in the field, since those are the areas most likely to develop ear mold. If ear mold is present, corn should be harvested as soon as possible.

Dry this corn to a moisture content of 14% if it is to be held in storage for more than just a short time.

You can also check corn for stalk rots by squeezing the lower stem with your thumb and fingers. If the stalks crush easily, they are probably infected with one of the stalk rot organisms and may lodge at any time. As with ear molds, check 100 plants to determine the percent of affected plants. If the percentage of stalk-rot-infected plants is high, corn should be harvested as soon as possible, even if it hasn't dried down adequately in the field. If the stalks are firm, the corn will probably be able to stand just fine for several more weeks if necessary.

GRAIN SORGHUM: Grain mold can occur on grain sorghum and turn the heads black or greenish-black. If sorghum currently has some grain mold, the mold problem may continue to worsen as long as the grain sorghum remains standing in the field. If there is no grain mold at this point it should not develop, since grain mold infections occur at an earlier stage of development.

As with corn stalk rots can be a problem in grain sorghum, so check the condition of the lower stalks now, just as described above for corn.

SOYBEANS: Soybeans can have diseases that affect seed quality such as pod and stem blight, anthracnose, or purple seed stain. However, the presence of these diseases is not the most serious concern for soybeans in the field at this point. The main concern is the potential for shattering. While the diseases listed above may get a little worse with time due to wet conditions, the losses incurred from them are not likely to be as great as the losses caused by shattering if harvest delays continue.

For further information regarding crop diseases, visit the Extension Office (215 Kansas, Courthouse, Alma; kamaverfaiksu.edu: 765-3821). For Bluestem Breezes archives, check out Wabaunsee, ksu.edu.



Copyright 2009 The Wabaunsee County Signal-Enterprise, Alma, Kansas. All Rights Reserved. This content, including derivations, may not be stored or distributed in any manner, disseminated, published, broadcast, rewritten or reproduced without express, written consent from SmallTownPapers, Inc.

© 2010 The Wabaunsee County Signal-Enterprise Alma, Kansas. All Rights Reserved. This content, including derivations, may not be stored or distributed in any manner, disseminated, published, broadcast, rewritten or reproduced without express, written consent from DAS.

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