Physoderma brown spot of corn is a fungal disease that may
cause your plant’s leaves to develop yellow to brown lesions. It is favored by
warm, wet conditions and, in the Midwest where most corn is grown, it is only a
minor issue. Be aware of this disease, especially if you live somewhere warmer
and with more humidity, like the southeast states of the U.S.
What is Corn Brown Spot?
This is a fungal infection caused by Physoderma maydis. It is an interesting disease, although it can be
destructive, because it is one of few that produce zoospores. These are fungal
spores that have flagella, or tails, and can swim around in the water that
pools in corn whorls.
The conditions that favor the infection are warm and wet,
especially when water collects in whorls. This is what allows the zoospores to
spread to healthy tissue and cause infection and lesions.
Signs of Corn with Brown Spot
The characteristic symptoms of corn brown spot infection are the formation of small, round or oval lesions that may be yellow, brown, or even a brownish purple in color. They multiply quickly and form bands across leaves. You may also see the lesions on the stalks, husks, and sheaths of your corn plants.
These signs can be somewhat similar to rust
diseases, so also look for a midrib lesion that is dark brown to
black in color to identify brown spot. The symptoms will most likely develop
before your corn has gotten to the tassel stage.
Physoderma Brown Spot Control
There are some fungicides that are labeled for physoderma
brown spot, but effectiveness may not be great. It is better to manage this
disease with cultural and preventative practices. If the disease has been an
issue in your area or region, try starting with resistant varieties of corn.
Infected residue of corn in the soil and promote
re-infection, so clean up debris at the end of each growing season or practice
good tillage. Rotate corn to different areas to avoid a buildup of the fungus
in one spot. If you can, avoid planting corn in areas that have high humidity
or are prone to standing water.
Physoderma brown spot of corn is a fungal disease that may
cause your plant’s leaves to develop yellow to brown lesions. It is favored by
warm, wet conditions and, in the Midwest where most corn is grown, it is only a
minor issue. Be aware of this disease, especially if you live somewhere warmer
and with more humidity, like the southeast states of the U.S.
What is Corn Brown Spot?
This is a fungal infection caused by Physoderma maydis. It is an interesting disease, although it can be
destructive, because it is one of few that produce zoospores. These are fungal
spores that have flagella, or tails, and can swim around in the water that
pools in corn whorls.
The conditions that favor the infection are warm and wet,
especially when water collects in whorls. This is what allows the zoospores to
spread to healthy tissue and cause infection and lesions.
Signs of Corn with Brown Spot
The characteristic symptoms of corn brown spot infection are the formation of small, round or oval lesions that may be yellow, brown, or even a brownish purple in color. They multiply quickly and form bands across leaves. You may also see the lesions on the stalks, husks, and sheaths of your corn plants.
These signs can be somewhat similar to rust
diseases, so also look for a midrib lesion that is dark brown to
black in color to identify brown spot. The symptoms will most likely develop
before your corn has gotten to the tassel stage.
Physoderma Brown Spot Control
There are some fungicides that are labeled for physoderma
brown spot, but effectiveness may not be great. It is better to manage this
disease with cultural and preventative practices. If the disease has been an
issue in your area or region, try starting with resistant varieties of corn.
Infected residue of corn in the soil and promote
re-infection, so clean up debris at the end of each growing season or practice
good tillage. Rotate corn to different areas to avoid a buildup of the fungus
in one spot. If you can, avoid planting corn in areas that have high humidity
or are prone to standing water.