If you haven't scouted your corn yet, now might be the time to do it. If you are lucky and have decent to good looking corn, a scouting trip now might save potential losses due to disease before the season is over.
Crop Watch 7/17: Spread in pollination between corn hybrids could help this field
Disease reports so far range from bottom leaves full of lesions in a susceptible hybrid to one farmer not finding any lesions as recently as 10 days ago. Despite that range of reports, Dave Nanda thinks the stage is set for the perfect storm in terms of corn diseases.
There is plenty of inoculum from last year and weather conditions have so far been favorable, particularly in the Eastern Corn Belt where moisture levels are high. All that's needed is a susceptible host.
Varieties that aren't rated as well as others on disease tolerance or resistance, especially for northern corn leaf blight and gray leaf spot, should be scouted immediately, he says. It may even pay to scout hybrids with supposedly better disease resistance packages. If the pressure is severe enough disease could become a factor even in those fields.
Where lesions, even a couple, are showing on leaves underneath the ear leaf, give serious consideration to applying fungicides when the stage of corn growth is right, Nanda says. Applying too early can risk injury to the corn, and in some cases, cause abnormalities in ear development. Most labels call for applications near brown silk.
Refer to the label for the product you are applying or will have applied to find the right time to treat the corn.
Crop Watch 7/13: Uncertainty creeps into Crop Watch '15 field
If lesions are on the ear leaf now, there's even more reason to pay attention, Nanda says. He notes that it is still early in the season for disease lesions to be showing up on leaves that high in the crop canopy. Action may be necessary.