Soybean South


Know Your Enemies

Correct soybean disease identification is by far the single most important disease management strategy, according to the University of Arkansas Extension Service.


Developing a disease management program involves an integrated approach using several efficient and economical disease management practices. Correct disease identification is by far the single most important disease management strategy.

The combined use of several disease management strategies which complement other “best farming” production practices will be more effective than any single control method. Some disease management procedures apply in all soybeangrowing areas of Arkansas, while others may be effective in specific situations. Consult your local county Extension agent for recommendations and incorporate as many of the following disease prevention strategies as possible into your disease management program.

Correct disease identification is by far the single most important disease management strategy.

Crop management considerations

Good crop management promotes plant health and vigorous growth, which enable the soybean plant to be more tolerant to most disease-causing organisms and often escape yield-limiting damage. This involves an integrated approach, which includes proper seedbed preparation, correct planting depth, balanced soil fertility, good internal and surface soil drainage and effective weed and insect management.

Planting resistant soybean varieties is the most efficient and least expensive disease management practice. But, resistance to all known diseases is not available, and pathogens may develop new races that overcome plant resistance. Many highyielding resistant soybean varieties are available for use against a number of potentially devastating diseases and should be planted wherever a serious soybean disease has been a continuous problem.

Identify local disease problems Knowing which damaging disease problems occur regularly in your local area and in each field on your farm is essential information you need prior to selecting top-yielding varieties for soybean production.

Consult your county Extension agent for variety selection recommendations. Use the Extension computerized soybean variety selection program to determine which variety is best suited to each field, especially if your disease situation includes stem canker or soybean cyst nematodes.

Some diseases such as frogeye leaf spot, sudden death syndrome and Phytophthora root rot may not be consistently yield-limiting in some areas of the state. In these situations, a less resistant variety with a higher yield potential may be suitable for your operation.

Loss from disease depends upon its severity. The production of no-till soybeans or continuous soybeans, especially the same variety in the same field, provides an environment in which diseases can be very damaging, even in areas where they have not been a recent problem.

An effective disease management program is essential for control of most soybean diseases and is based largely upon disease prevention strategies.

The University of Arkansas Cooperative Extension Service provided information for this article.

Louisiana Rust Control Tip

LSU AgCenter plant pathologist Boyd Padgett recalls an approach to a situation that occurred last year that farmers may want to consider as an option in the 2008 season if the same thing happens again.

According to Padgett, soybean growers had applied a strobilurin fungicide (with or without Topsin M, depending on the individual situation) around the R3 stage. Later in the season, if their parish happened to light up for rust and the timing worked out, growers tankmixed a triazole fungicide with the insecticide they were going to apply for stink bug control.

This approach has the potential to save money by addressing two problems at one time. – Carroll Smith