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Although diseases of soybeans were of little or no importance, the diseases of soybean have assumed increasing importance with the more regular appearance of this crop in rotations and as the acreage has expended. How to control the diseases of soybean plants? Okey, we will explain the diseases of soybean and how to control them.
The first diseases of soybean is bacterial blight, bacterial blight attacks the leaves, stem, and pods of the soybean plants. Small, irregular, water-soaked lesions are produced during early stages of infection. As the disease progresses, the lesions become joined together, they turn brown, and eventually dry out.
Infected seed is the primary source of infection, but this disease of soybean also overwinters on crop residues. Under favorable conditions, the bacteria spread rapidly from infected to healthy plants during the growing period.
Control this disease of soybean, i.e. the use of seed that is not infected provides some measure of control. The greatest promise for control, however, lies in the development of varieties resistant to this disease of soybean.
The second diseases of soybean is mosaic, mosaic is a virus disease that is spread through the use of infected seed. Infected plants are stunted, and they have small, oddly-shaped, crinkled leaflets which are characterized by a more deeply green color along the veins. Seed pods of diseased soybean plants are also stunted, and the yield and quality of the seed are reduced.
Control this virus of soybean, i.e. no resistant varieties are currently available. The greatest promise for control lies in the development of varieties resistant to this disease of soybean plants.
The third diseases of soybean plants is brown stem rot, brown stem rot occurs primarily in the north central states. This disease of soybean is caused by a soil fungus which enters the plant through the roots and the lower part of the stem. Infected soybean plants are characterized by a dark brown internal discoloration. During the latter part of august or early September a sudden browning of the intervein leaf tissues may take place. Severe infestations cause lodging and reduce the size of seed. Crop rotation is recommended as the present control measure, but the development of disease resistant varieties holds the generate promise for effectively controlling this organism.
The fourth diseases of soybean plants is stem canker, stem canker is a fungus disease which occurs most frequently in the Midwestern states. The fungus makes its entry into the stem at the base of a branch or leaf. A brown to black, sunken area develops on the stem and eventually completely encircles it, thus cutting off the movement of water and nutrients. The entire plant wilts, the leaves dry up, and the plant dies. This disease of soybean usually does not appear until after mid-july in the southern part of the cornbelt amd after mid-august in the northern states. This disease of soybean plants lives on the seed, plant residues, and in the soil. Crop rotation and the use of disease free seed are recommended as control measures. No resistant varieties are available at the present time.