Burke – Jenkins Ag News

Bermudagrass Stem Maggot

I received my first call last week on the bermudagrass stem maggot. I have heard about this pest in extreme southeast Georgia, but this is the first time I have witnessed the damage in Jenkins County. Why is this important? This is important because we have many bermuda hayfields and pasture in our county that stand to be severely damaged. Unfortunately, we have very limited information on the stem maggot, so we are having to learn as we go. When scouting for damage, look for browning on the top node of the plant. The majority of the plant will appear green. However, the top part of the plant will be dead. The symptoms resemble grass that was recently sprayed with liquid nitrogen, which often displays a temporary burn after application. The stem fly maggot starts its life cycle with the adult laying an egg at the base of the infected node. The egg hatches into a larvae which tunnels its way through the infected stem, and kills it. If you have an infestation, the best thing to do is go ahead and cut it. It will not get better and the damaged crop will only serve to shade and hold back future yields. After you cut and bale the hay, spray a pyrethroid immediately, which kills the adult flies. Another pyrethroid application needs to be applied approximately two weeks later. This will keep the flies suppressed until it is time to cut again. On a positive note, this pest can not be transferred from field to field, as overwintering occurs in the soil. As always, it is imperative that you properly diagnose the problem before taking control measures. Hopefully, this won’t turn into a regular problem!

stem fly field

This hayfield is showing stem maggot symptoms. Note the “burnt” top part of the plant. The symptoms resemble hay that was recently fertilized with liquid nitrogen.

stem fly2

Close-up view of damaged plants.