–by Jeff Whitworth — Field Crops, Entomology
Japanese beetles (see fig 1-adults) were 1st recorded in Kansas in 1992. However, they have been in the U.S. since about 1916, and have been a serious pest of ornamental and agricultural crops in several states east of Kansas for many years. They seem to be slowly spreading across Kansas from east to west, and there have been reports of small but dense populations of Japanese beetles extending west past Interstate I-35 (see fig 2-soybean plants defoliated by adult Japanese beetles in Republic Co. in 2021-photo by J. Hammer). Japanese beetle larvae, commonly called white grubs, can now be found in some no-till areas of fields that were infested with the adults in 2021 (see fig 3 by J. Hammer). This is becoming more common because the adults feed for a short time then fly to nearby undisturbed areas to oviposit. Depending upon when these adults emerge they may feed on young corn leaves, silks, and/or young soybean leaves, as far as agricultural crops are concerned.
Figure 1 Adult Japanese beetles
Figure 2 Soybean defoliation by Japanese Beetles in 2021, Republic Co., KS
Figure 3 Japanese beetle larvae, 2022, from field in Fig. 2.