With the lack of rainfall in much of Louisiana, Dr. David Kerns and I have been receiving more calls regarding chinch bugs in late corn and grain sorghum. Chinch bugs are small insects 1/5 to 1/6 inch in length, with a black body and white front wings creating a white X when viewed from above. Immature chinch bugs resemble the adults only smaller and lacking wings. Nymphs range in color from reddish brown to black in later instars.
Chinch bugs are typically active on grasses in and around fields and movement to seedling corn and grain sorghum is common. Damage by both adults and nymphs causes corn to have a reddish appearance on the stem and leaves.
Continued feeding can cause plants to wilt and eventually die. Corn is most susceptible in the seedling stage when plant growth is slow and conditions are dry. Seed treatments and soil insecticides will typically give an 18 day window of protection after emergence. However, during dry conditions water stressed plants are more susceptible to injury and seed treatments may not provide as long of protection as under adequate moisture conditions. Once plants have surpassed the most susceptible stage, chinch bug damage becomes less of an issue.
If plant growth is slow and chinch bug numbers have reached 5 or more on 20% of plants 6 inches tall or less, a foliar rescue treatment should be applied to stop injury.
When using ground equipment, a high volume, high pressure sprayer delivering a minimum of 20 gpa should be used. Aerial applications should only be used if ground equipment cannot make it across a field.
If you have any questions or concerns feel free to contact Dr. David Kerns or Sebe Brown for more information.
Dr. David Kerns Cell: 318-439-4844 Office: 318-435-2157
Sebe Brown Cell: 318-498-1283 Office: 318-435-2903