In South Dakota, sunflower flowering is well underway. That means it is time to start scouting fields for red sunflower seed weevils. During the last two years, red sunflower seed weevil populations have been higher than normal with areas that exceeded the thresholds by as many as 300-500 adults per sunflower head.
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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.
Northern corn leaf blight was found in a few corn fields scouted recently. The disease was found at very low severity, except occasionally when an individual plant was found with several lesions on one leaf.
August 12, 2019
SDSU Extension staff will be hosting several forums during Dakotafest 2019 held August 20-22 on the Schlaffman Farm near Mitchell, S.D., (2300 E Spruce Street) inside booth #600.
While scouting sunflower near Sturgis this week, we came across outbreak levels of checkerspot caterpillars that were defoliating the plants. Similar sightings have been reported throughout Western and Central South Dakota in recent weeks.
Goss’s bacterial blight was found in a few corn fields scouted the week of August 5, 2019. The severity ranged from low to moderate, where at least 25 percent of the leaf area was killed by the bacteria infection on several plants. The disease is characterized by long, tan-gray lesions with wavy margins found in the center of the leaf or along the edges of the corn leaf blade.
According to the latest climate outlook update, odds are favoring that August 2019 will be cooler than average. The update was released by NOAA’s Climate Prediction Center on July 31, 2019.
The 2019 wheat harvest is well underway in South Dakota, with many acres of winter and much of the spring wheat crop left to harvest. To date, reports on yield and quality have been variable, depending on when the crop was seeded, weather conditions at important growth stages (such as flowering and grain fill) and disease pressure throughout the season.
Is your corn developing spots? Corn fields have been found with what appears to be Holcus spot, a bacterial disease. Upon further investigations, the leaves were found to be negative for any plant pathogens.