Common Corn Rust
About the Disease: Common Corn Rust is mainly caused by the fungus and seems to be widespread in plants like corn. This is a very common condition in United States of America. The sweet corn is actually highly resistant to many of the diseases. But the fruits still face some problems in combating certain diseases.
Symptoms: During the initial stages of the common corn rust disease, there will be few chlorotic flecks that can be seen on both the top as well as the bottom surface of leaves. The leaves lose their characteristic green color and will turn yellow and brown. On both the upper and the lower surfaces of each leaf, the flecks will be formed as oval shaped pustules.
These pustules will be reddish brown in color. They also seem to be well elongated, giving the leaf, a characteristic rusted appearance. The pustules will turn into black or brown spots at a later point of time. This is not considered to be a very severe condition in plants. The fungal spores will enter the leaf through the epidermis.
Pathogen Involved: The disease is caused by the fungus, Puccinia sorghi
Time of Occurrence: This mainly occurs in the humid climate. In this condition, the growth of the fungus cannot be prevented.
Conditions Favoring Disease: There are certain conditions that might act favorable to the development of the disease. This includes the humid weather condition. The fungi thrive in cold condition. The temperature of 66 F is an optimal one. The spores of the fungus are carried away by the air. The inoculums might not survive for a long time.
Disease Management: The regular use of fungicide can be carried out as a protective measure. But you need to realize that too much spraying of fungicide can also be hindering the growth of plants. Thus the best way to avoid this disease, without affected the other crops, is to practice crop rotation. You need not grow corn in the same place, year after year.
There are so many other non grass crops that can be grown in the same plot. There are special foliar fungicides, which are applied only on the leaves. This can be used in the production fields. Another best option to prevent this disease is to grow the hybrid varieties that are resistant to these fungi. Thus, even though the fungus thrives, it will not be having any effect on the growth of the plant. Resistant hybrids are surely a good choice.