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A Case of Mistaken Caterpillar Identity
Tweets about European corn borer (Ostrinia nubilalis) caterpillars in the stems of conventional corn and feeding in the whorls of corn are crossing my Twitter feed. Unfortunately, there is a problem with some of these tweets. Not all of the caterpillars that are being identified as European corn borer caterpillars are actually European corn borer caterpillars!
Bean Leaf Beetles Are Back: Adults Observed Near Beresford
Earlier this year, we observed a large emergence of overwintering bean leaf beetles throughout much of the state. We are again observing quite a few bean leaf beetles beginning to emerge. These emerging beetles are the result of overwintering beetles mating and laying eggs.
How to Scout For Soybean Gall Midge
Soybean gall midge have been reported in three counties in South Dakota in the past week: Clay, Union and Lincoln. Scouting for soybean gall midge can be as simple as finding wilting or dying plants along the edge of the field, or it can be rather difficult if the plants are currently asymptomatic.
Dectes Stem Borer Adults Active in Sunflower
In South Dakota, one of the insects that is commonly observed in sunflower is the Dectes stem borer larva. At this point in the season, adults are beginning to become active with females laying eggs in sunflower plants.
Say’s Stinkbug Present in Western S.D. Wheat: Do I Spray?
While looking at winter wheat at the new SDSU West River Research Farm near Sturgis, we came across some very large stinkbug populations in a few areas of the field. The stinkbugs we observed were the Say’s stinkbugs. Although stinkbugs have the potential to reduce wheat yields, this is attributed with feeding that occurs between the late boot and milk stage.
Watch for True Armyworms in Wheat
This week we observed some true armyworm caterpillars in winter wheat fields. The caterpillars were still relatively small, which means they will continue feeding for some time. So far, the true armyworm caterpillars were still feeding on the leaves of the nearly mature wheat, but they have the potential to also clip heads off of the plants.
Bacterial Blight Common in Soybean Fields
Several soybean fields scouted the week of July 15, 2019 were found with bacterial blight developing. The frequent rains experienced in most soybean growing counties have led to the development of this disease. Bacterial blight affected leaves are most evident on younger leaves in the upper canopy.
Fusarium Root and Crown Rot Developing in Corn
A few corn fields scouted in Brookings County were found with Fusarium root rot at low levels. Infected plants were wilting and upon splitting of the lower nodes revealed brown discoloration of the pith. Root and crown rots developing in corn after the seedling stage are usually caused by Fusarium spp. and can be enhanced by injury to the roots or crown, mainly by insect feeding.
Small Grain Pre-Harvest Options
Consider pre-harvest herbicide applications in crop ground planted with small grains that are grown for seed or forage. Dense weed populations may inhibit harvest, therefore proper control of them early in the growing season is best.
Herbicide Interactions With Cover Crops After Oats
After oats have been harvested, options exist to keep a living root in the soil. This can be done through growing cover crops. In 2018 an on-farm trial was preformed near Salem, South Dakota to observe how cover crops grown after oats would germinate after common herbicides had been applied.