Dealing with corn ear rot
By
John Grimes-
Discussions about the lousy weather that we have been experiencing and its effect on grain harvest is the current “hot topic” in the farming community these days. Stress levels are running high and you can understand why. Yield potential for this crop is very good and farmers can’t get the crop out of the field. A delay in grain harvest means a delay or, in some cases, an elimination of wheat planting.
Harvesting during wet field conditions can have along term impact on future crops in the field. Harvesting grains at higher moisture levels will increase drying and storage costs. You get the idea. Let’s look at something more positive. How about those 4-2 Bengals? The season thus far has been a pleasant surprise.
Corn ear rot
Several different types of ear rot problems are showing up in some of Ohio’s corn fields this year, and lots of questions are being asked about these problems and how to tell them apart. Reported symptoms range from those typical of common ear rots to relatively uncommon symptoms such as blackish mold growth on the ear. It is important to identify ear rot problems before harvest because some ear rot fungi produce mycotoxins that are harmful to livestock.
Good indicators of potential ear rot problems are:
n Wet weather conditions late in the season.
n Frost occurring before maturity.
n Corn standing in the field for an extended period in late fall.
n Delayed maturity (dry-down).
n Bird and insect damage.
n Hybrid susceptibility.
n Ear drying-down in an upright position.
Generally, it is fairly easy to tell ear rots apart based on the color of the fungal growth on the ear, how the mold develops, and how the moldy kernels are distributed on the ear.
The three most common ear rots in Ohio are Gibberella, Diplodia and Fusarium ear rot. Gibberella ear rot, is the most prevalent of the ear rots this year; however, we have also received reports of Diplodia ear rot in some fields. With Gibberella ear rot, the fungus enters the ear tips through the silk channel. Gibberella ear rot develops best when cool temperatures and frequent rainfall occur during the 3-week period after silk emergence. Hybrids that dry-down with the ear in a declined position are less likely to have problems with Gibberella and other ear rots.
Like Gibberella ear rot, Fusarium ear rot also causes pinkish discoloration of infected kernels, the fungus also enters through the silk, and the disease develops best when warm, wet weather occurs during the 2 to 3 weeks period after silking. However, with Fusarium ear rot, the pink moldy kernels are usually scatters all over the ear. As the disease develops, the infected kernels may become tan or brown or have white streaks. Ears that dry-down in declined position and those free of injuries and well covered with husks are less prone to Fusarium ear rot.
Diplodia causes a thick white mold to grow on the ear, usually starting from the base and progressing toward the tip. Infection can begin before tassel emergence up to silking, and disease development is favored by wet weather and mild temperatures during early ear development. As the disease develops, the entire husk becomes bleached, covered with whitish-gray mold, and glued to the kernels. Infected ears are usually lightweight and may become rotten.
Other important, but less common ear rots:
n Aspergillus ear rot: Yellowish-green to dark green powdery mold on the ear that typically develops under hot, dry conditions. This ear rot may lead to aflatoxin contamination of grain.
n Cladosporium ear rot: Dark, greenish-black streaks scattered over the ear. This ear rot is often associated with insect, hail or frost damage.
Garden cleanup
You’ve seen this advice before, but there probably hasn’t been a year when putting your vegetable garden to bed properly should be heeded more than this year. The wet growing season has left lots of plants and old produce in our gardens loaded with disease. Many vegetable gardeners are wrapping up the season at this point, as cooler temperatures and less sunshine have caused vegetables to slow in production. Now is the time to think about cleanup and making notes for next season.
Garden cleanup is important for disease and insect management. Spent plants can be removed now, with a total clean-up of all plants after a killing frost.
Make sure that diseased debris is removed from the garden. Take special care to remove all tomato and potato vines as well as fruits and tubers; all plant parts harbor blights that may cause severe losses. Be sure to remove all vines and fruits of cucumber, melon, and squash.
If corn smut was a problem, destroy all remaining galls by burning, burying, or depositing in yard waste, to reduce inoculum for next season. After cleaning up all the crop debris this fall, spade or rototill the soil to bury any that remains.
Make notes about how well certain crops did and if you would grow them again, and how you would do things differently next season.[[In-content Ad]]
Harvesting during wet field conditions can have along term impact on future crops in the field. Harvesting grains at higher moisture levels will increase drying and storage costs. You get the idea. Let’s look at something more positive. How about those 4-2 Bengals? The season thus far has been a pleasant surprise.
Corn ear rot
Several different types of ear rot problems are showing up in some of Ohio’s corn fields this year, and lots of questions are being asked about these problems and how to tell them apart. Reported symptoms range from those typical of common ear rots to relatively uncommon symptoms such as blackish mold growth on the ear. It is important to identify ear rot problems before harvest because some ear rot fungi produce mycotoxins that are harmful to livestock.
Good indicators of potential ear rot problems are:
n Wet weather conditions late in the season.
n Frost occurring before maturity.
n Corn standing in the field for an extended period in late fall.
n Delayed maturity (dry-down).
n Bird and insect damage.
n Hybrid susceptibility.
n Ear drying-down in an upright position.
Generally, it is fairly easy to tell ear rots apart based on the color of the fungal growth on the ear, how the mold develops, and how the moldy kernels are distributed on the ear.
The three most common ear rots in Ohio are Gibberella, Diplodia and Fusarium ear rot. Gibberella ear rot, is the most prevalent of the ear rots this year; however, we have also received reports of Diplodia ear rot in some fields. With Gibberella ear rot, the fungus enters the ear tips through the silk channel. Gibberella ear rot develops best when cool temperatures and frequent rainfall occur during the 3-week period after silk emergence. Hybrids that dry-down with the ear in a declined position are less likely to have problems with Gibberella and other ear rots.
Like Gibberella ear rot, Fusarium ear rot also causes pinkish discoloration of infected kernels, the fungus also enters through the silk, and the disease develops best when warm, wet weather occurs during the 2 to 3 weeks period after silking. However, with Fusarium ear rot, the pink moldy kernels are usually scatters all over the ear. As the disease develops, the infected kernels may become tan or brown or have white streaks. Ears that dry-down in declined position and those free of injuries and well covered with husks are less prone to Fusarium ear rot.
Diplodia causes a thick white mold to grow on the ear, usually starting from the base and progressing toward the tip. Infection can begin before tassel emergence up to silking, and disease development is favored by wet weather and mild temperatures during early ear development. As the disease develops, the entire husk becomes bleached, covered with whitish-gray mold, and glued to the kernels. Infected ears are usually lightweight and may become rotten.
Other important, but less common ear rots:
n Aspergillus ear rot: Yellowish-green to dark green powdery mold on the ear that typically develops under hot, dry conditions. This ear rot may lead to aflatoxin contamination of grain.
n Cladosporium ear rot: Dark, greenish-black streaks scattered over the ear. This ear rot is often associated with insect, hail or frost damage.
Garden cleanup
You’ve seen this advice before, but there probably hasn’t been a year when putting your vegetable garden to bed properly should be heeded more than this year. The wet growing season has left lots of plants and old produce in our gardens loaded with disease. Many vegetable gardeners are wrapping up the season at this point, as cooler temperatures and less sunshine have caused vegetables to slow in production. Now is the time to think about cleanup and making notes for next season.
Garden cleanup is important for disease and insect management. Spent plants can be removed now, with a total clean-up of all plants after a killing frost.
Make sure that diseased debris is removed from the garden. Take special care to remove all tomato and potato vines as well as fruits and tubers; all plant parts harbor blights that may cause severe losses. Be sure to remove all vines and fruits of cucumber, melon, and squash.
If corn smut was a problem, destroy all remaining galls by burning, burying, or depositing in yard waste, to reduce inoculum for next season. After cleaning up all the crop debris this fall, spade or rototill the soil to bury any that remains.
Make notes about how well certain crops did and if you would grow them again, and how you would do things differently next season.[[In-content Ad]]