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Bermudagrass Stem Maggot in Hayfields

By Will Hudson, Lisa Baxter and Dennis Hancock

We’ve had a number of calls from growers and agents in the last week or so concerned that they should be spraying for BSM.  Even in south GA, the flies are just now starting to show up.  You may be able to find some damaged stems, but most of the widespread browning of the grass is probably due to the extreme heat and dry weather following an unusually cool and wet spring.  BSM damage kills just the last 2 leaves, and does not turn the tips of the leaves brown.  They generally do not affect leaves lower on the tiller than the top 2.  Even in our well-watered research plots in Tifton, we are only seeing 10-20% damage in the most susceptible varieties.  The current drought situation has many producers delaying their hay harvest.  This means we have more mature bermudagrass than usual (and so there appears to be more damage).  There is likely no need to spray yet, but growers should be alert and be ready to spray after the next cutting if there is a noticeable amount of damage.