Bermudagrass Stem Maggot

Don W. Clark Jr. - Grady County ANR Agent

There is a relatively new pest that has had a major impact on Bermudagrass hay production in South Georgia and North Florida.  The Bermuda grass stem maggot, native to Southeast Asia was found in Tift, Pierce, and Jeff Davis counties in 2010.  I found it in Grady County in 2011, it was also found in many South Georgia and North Florida Counties in 2011 and 2012 as well.

            If your Bermuda grass hay field looks like it has been damaged by frost in the middle of the growing season, you are probably experiencing damage from this insect.

            The larval (maggot) stage of the BSM is what is causing the damage.  This maggot is inside the stem when the damage is done.  The adult fly lays its eggs on the Bermuda grass pseudostme (folded leaf blades).  Upon hatching, the larva works its way toward a node, where the leaf blade emerges from the stem.  As the larva develops, it feeds on the node.  This feeding results in the browning of the last one to three leaf blades.

            In 2011 and 2012 I consulted with Dr. Dennis Hancock and Dr. Will Hudson for the purpose of setting up a test in an effort to find a control strategy.  Some observations we made were that BSM was much more common on small stem varieties like Alicia than large stem varieties like Tifton 85 and Coastcross.  Also we needed to control the adult fly because the maggot would be difficult to control protected by the stem.  I set up several tests in 2011 and 2012 in an effort to find an acceptable control strategy.  We used low rates of several pyrethroid’s and three different spray schedules.

     My three growers used different spray schedules as follows:

A.   Treated behind the baler (3 days after cutting) and again 7 days later.

B.    Treated 7 days after cutting and again 7 days later.

C.    Treated 5 days after cutting and again 10 days later.

All three of my hay producer’s experienced similar control.

Dr. Hancock, Dr. Hudson, and two graduate students are also continuing to work on control strategies for this pest.  Hopefully we will have more information on control of this pest very soon.   For more information check out this factsheet:  Biology and Management of Bermudagrass Stem Maggot.