Japanese Beetles and Masked Chafers on the Wing

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Japanese Beetles (Popillia japonica) are on the wing in southern and central Ohio with some localized heavy populations.  Adding to the potential grub-party, I've been capturing a few Southern Masked Chafers (Cyclocephala lurida) around my porch lights at night in the southwest part of the state.  Northern Masked Chafers (C. borealis) appear to be lagging behind.

 

Japanese Beetle

 

 

Japanese beetle numbers have been on the downswing over the past several years in much of Ohio with high populations only occasionally being reported.  This has been particularly true in southern Ohio.  However, damage to turfgrass from white grubs has continued to be reported along with the accompanying excavation damage from skunks and raccoons in search of grub meat.

 

It is common for people to assume that white grubs found beneath turfgrass in Ohio are Japanese beetle larvae.  However, the grubs that have been most responsible for damaging turfgrass and drawing animal raiding parties in the southern part of the state were the larvae of masked chafers.

 

Chafers

 

Chafers

 

The reason the great grub switcheroo has been so successful is that masked chafer beetles operate below the radar:  they fly at night and do little to no noticeable feeding damage.  Of course, Japanese beetles are day fliers and are notorious for their leaf skeletonizing damage. 

 

I'm not making any predictions regarding white grub populations this season.  Japanese beetles may be making a "comeback"; however, it's still too early to determine whether they will lay enough eggs to produce damaging numbers of white grubs.  Much rests on chafer populations.  Thus far, I'm not seeing adult numbers nearly has high as last season and I've yet to see my first northern masked chafer.

 

May/June Beetle

 

Turf managers should not confuse masked chafers with May/June Beetles.  We experienced a heavy emerge of the poorly named May/June Beetles in April in southwest Ohio.  There are five species of beetles in the genus Phyllophaga in Ohio that share the May/June common name.  All fly at night and are notorious for being attracted to porch lights where they bounce off walls, doors, windows, startled homeowners, etc.  At least one of the species strongly resembles chafers; however, the grubs prefer pasture grasses, so they do not damage turfgrass.