Insects Out and About: Armyworms, Rose Chafers, and others

Armyworms, Rose Chafers and a few others are out and about.

Three different insect pests are common enough this year that a friendly reminder to be on the lookout for them is in order.

The weekly Department of Agriculture Pest Update newsletter indicates that Armyworms have been found in pockets around the state.  They are not widespread, but in the pockets where they have been found there has been some significant feeding.  So, looking at fields to see if one of the pockets is in your crops is worth doing.  It would be worthwhile to spot check including, but not limited to, winter wheat, corn and soybean after a grass cover crop and new alfalfa seeding especially if there is a connection with grassy weed growth or cover crop.  You may find armyworm damage to be spotty or “clumped” within fields as well as on the local and greater landscape level.  This makes scouting important, yet frustrating.  A single field may be devastated while all others in the area look good.  It can be very frustrating, and damage easily missed until it is too late.  Unfortunately, when it is too late you will know it.  Above ground Bt traits vary in their control of armyworm.  Only those trait packages with Vip3A offer control.

Rose chafers were later emerging this year than normal due to the cool spring.  These beetles are common again this season and reports of damage to grapes, raspberries, strawberries, fruit trees and ornamentals are increasing. Chafer feeding is expected to continue for 2-3 more weeks and will subside in most areas by mid-July. Insecticides are usually not needed to control this early summer defoliator, but if you want to protect ornamental plants they are drawn to or have a very heavy infestation on a fruit crop.  A fact sheet with information on insecticide to control them can be found at  . Make sure the product you use is labeled for the plant/crop you are applying it to and follow all label directions.

Spotted Wing Drosophila (SWD) Fly emergence began in western Wisconsin by June 21. The first capture of SWD adults in survey traps should be viewed as an early warning to fruit growers to increase monitoring efforts and make preparations for SWD management. This invasive pest is particularly challenging for organic growers due to the limited number of organically approved and effective insecticides. Information is available at this website for managing this pest: . Controlling SWD requires a rigorous, persistent and diverse management plan.

Potato leafhopper numbers in alfalfa so far have been low in fields scouted and second cutting either is or will begin soon which will help keep numbers low, and soybean aphid numbers have also been low in fields scouted so far.  But it is still a good idea to keep an eye on fields for these pests.


If you have any questions, please contact:
Bill Halfman, Monroe County Extension Agriculture Agent,
Phone: 608-269-8722 or Email: