Kansas State University


Extension Entomology

Tag: stages

Japanese Beetles

— by Dr. Jeff Whitworth and Dr. Holly Schwarting

Adult Japanese beetles have been detected around north central Kansas in the last 7-10 days.  These adults may feed on corn, sorghum, and soybean leaves, as far as field crops are concerned, and may cause some “window paneing” much like the leaf feeding of adult corn rootworms.  However, this leaf feeding usually is of little consequence.  In corn, these beetles will be attracted to the silks and, as they can be very veracious feeders, may clip these silks at a pretty good rate.  Fortunately, they are usually localized to small “hot spots” in some fields and thus do not really justify any insecticide application.  These adult Japanese beetles may be active for another couple of weeks, after which only eggs and larvae will be present, and these life stages are not a threat to these crops.


Western Corn Rootworms

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Most of the corn in north central and south central Kansas is at, or just passed, the whorl stage and there seem to be very few whorl-feeding larvae.  However, the Western corn rootworm adults are just starting to emerge from the soil.

WCR adult 1

WCR adult 2

These adults were 1st detected on 23 June in Dickinson County.  These beetles are feeding on the leaf tissue as the plants are not yet tasseling or producing silk/pollen.  There is quite a disparity of rootworm life stages in this same field.  There are many adults in the northwest corner but still mostly larvae, even relatively small ones, in the southeast corner of this same field.  Some of the feeding damage caused by the rootworm larvae can be seen in the last photo.

WCR larvae

WCR larval feeding damage