Well, it is that time of year again, at least weather-wise, to be on the lookout for chinch bugs.
Chinch bugs overwinter in Kansas, as adults, usually at or around the base of bunch grasses. But, in milder winters they have successfully overwintered in no-till fields that have relatively thick residue reports Jeff Whitworth, K-State Extension Entomologist.
When wheat breaks dormancy, these adults move from the overwintering site to wheat where they start feeding, mating, and depositing eggs. These adults do not feed as much as the nymphs, but occasionally, if conditions are relatively dry, this feeding may stress some of the wheat. As the eggs hatch and nymphs emerge, they too start sucking the juice from wheat plants until the plants start drying. As the wheat senesces and thus, plants lose their moisture, these nymphs must move to find more succulent plants. Thus, any corn, sorghum or feed adjacent to these infested wheat fields attract this "walking" generation says Whitworth.
All corn and most sorghum seed are pretreated with an insecticide. These seed treatments work. But, remember the bugs must suck a little of the juice from the plant to get a dose of the insecticide, and if there are enough bugs removing enough of the plant's fluid this feeding may still result in death of the plant even though it kills the bugs. Most seed treatments protect the seed and seedling for about 30 days after planting.
Thus, as the wheat starts senescing, it is a great time to assess or monitor chinch bugs. Identification - adults are about an 1/8-inch-long, black bodies with white wings folded over their backs, featuring a distinctive black "X" mark. Nymphs are bright red when they hatch, darkening to black with a noticeable white band across their midsection until wing buds develop.
Just move into the wheat field and push the wheat aside in square foot sized areas and count the number of chinch bugs. If you do this in several areas of the field and the average
is 1 or more adults or 4 to 5 nymphs per square foot--then it would be prudent to delay planting, or if it is planted to corn which has already germinated, a barrier insecticide treatment/spray may be considered before the bugs move out of the wheat.
Preventative options to consider - avoid planting sorghum or feed directly adjacent to thin, stressed wheat stands. You can plant a 50-foot strip of an early-maturing sorghum or feed trap crop between wheat and sorghum fields. If migrating bugs become numerous, you can treat this barrier strip with insecticides before they move into the primary crop.
Weather drives insect development and we have had a relatively mild winter, so many insect populations seem to be a couple of weeks ahead of their average development time. During the last 3-4 years we had relatively large chinch bug populations going into fall and overwintering. This has led to relatively large populations of chinch bugs throughout the next growing seasons. This year, so far, seems to be setting up the same, with the potential of healthy populations of chinch bugs again this summer, says Whitworth.
For more information about chinch bug management, please refer to the KSU 2026 Sorghum (or Corn) Insect Management Guides. Information provided by Jeff Whitworth, K-State Extension Entomologist.
Stacy Campbell is a Crop Production Extension agent in the Cottonwood District (which includes Barton and Ellis counties) for K-State Extension. You can contact him by e-mail at scampbel@ksu.edu or by calling 785-628-9430.