Many South Dakotans are dealing with flood issues following recent rain and damaging storms.
SDSU Extension publishes the South Dakota Pest & Crop Newsletter to provide growers, producers, crop consultants, and others involved in crop production with timely news pertinent to management of pests, diseases, and weeds in South Dakota.
Some portions of soybean fields may show clusters of plants yellowing while the rest of the field is still green. One of the factors that could lead to soybean plants showing early yellowing in clusters is soybean cyst nematode (SCN).
This year’s struggles with weather and climate are continuing this fall. Late planting of corn and soybeans in the spring have now combined with near average or cooler than average summertime temperatures. This combination has led to slow crop growth and the need for an extended frost-free season to ensure these crops reach maturity.
Although many soybean fields are behind schedule, so are the soybean aphid populations. In many reported areas, there are hotspots within a field where a few soybean plants may be heavily infested.
Sudden death syndrome of soybean is starting to develop in soybean fields in South Dakota. Fields currently being found with sudden death syndrome have symptomatic plants scattered within the field, but continued disease development may lead to larger clusters of infected plants.
Interest in cover crops has increased in recent times. Cereal rye has been a cover crop of choice among corn and soybean growers in South Dakota due to its superior tolerance to cold temperatures and ability to overwinter in a Northern climate.
Frogeye leaf spot, also known as Cercospora leaf spot, was found in several soybean fields scouted the week of August 19, 2019. Frogeye leaf spot is characterized by irregular to circular lesions, which are tan-to-gray in color with reddish-purplish borders.
As the season continues, so is our soybean gall midge scouting efforts. For much of South Dakota, the soybean that are infested with soybean gall midge are asymptomatic. That is, they show limited signs of infestation, but we can still find the larvae of the soybean gall midge in the stems.
Populations of green cloverworm, a caterpillar pest of soybean, have been increasing over the last couple of weeks in South Dakota. Although green cloverworm caterpillars feed on soybean leaves, defoliation rarely results in economic loss. However, reports of increasing populations of green cloverworm and increasing amounts of defoliation suggests that scouting for this insect pest is warranted.