Is your corn suffering from drought or Goss’s Wilt?
Once you have it, you’ll have it forever, and that is not a good thing, because the bacteria which cause Goss’s Wilt will stay in crop residue over the winter to infect the next crop. The problem is moving rapidly from the Western Corn Belt eastward, and heavy winds that blew through the Eastern Corn Belt this weekend may have helped spread it even faster.
Susceptibility is about the only defense against the bacteria, which now claims a territory as far east as Indiana, and as far north as Canada. DuPont Pioneer plant pathologist Scott Heuchelin says a corn grower should learn the symptoms of the disease and whether their hybrids are susceptible. He says winds, sandblasting, and hail can damage the plant enough for the bacteria to splash up from the soil and enter the plant. Once that happens, there is no chemical cure and once a field is infected, the disease will persist in a field and reduce yields as long as susceptible hybrids are planted.
Goss’s wilt will initially cause leaves to deteriorate, then reduce stalk quality and diminish yields. Heuchelin says the disease can be confused with drought stress and sunscald along with other leaf blights and nutrient deficiencies. He says there are two phases of the disease, and the first phase can begin at any point in the life of the corn plant.
The seedling stage begins with a systemic infection that discolors vascular tissues and produces a slimy stalk rot. The bacteria will build up in vascular bundles and halt the ability of the plant to get water into the growing tissues. The growth is stunted, and the plant will wilt and die and appear to be the victim of drought stress, which is a great camouflage in a year like this one.
The midseason symptoms include freckles on the leaves near or inside the lesions on the leaves. There will also be shiny or glistening patches of dried bacterial ooze on the lesions, which Heuchelin says appear to be a thin layer of varnish. There will also be water-soaked streaks on the leaves with tan or gray lesions that run the length of the leaves.
If you have fields of continuous corn, or a heavy growth of grassy weeds, or excessive crop residue, or use minimum tillage practices, the chances are increased that your fields will have the disease present, and will show up if your hybrids are susceptible. Goss’s wilt likes an environment of heavy rainfall, followed by hot and humid conditions.
Management of Goss’s wilt is limited at this point, other than planting resistant hybrids. Heuchelin says since the carrier is a bacteria—it will not be controlled by a fungicide. And he says target your seed selection to a hybrid that has resistance. He also said that spreading the disease can be avoided with debris management, which is the source of the bacteria. Management is achieved with crop rotation, along with tillage, and cleaning any tillage equipment between fields.
Goss’s wilt is a bacterial-spread disease in corn, which attacks leaves, stalks, and leave the plant diminished and unable to produce an ear. The bacteria thrive in crop residue and can be spread by winds, which have carried the disease eastward across much of the Corn Belt. There are no cures for the disease, other than planting resistant hybrids, and some field management techniques can aid in the effort to reduce the spread of the disease.
Source: FarmGate blog