Sorghum Tips

Sorghum Midge

This sorghum tip was provided by:
Dr. Ed Bynum
Texas A&M AgriLife Extension Entomology, Amarillo
806-677-5600, ebynum@ag.tamu.edu

Statewide

Sorghum midge, Stenodiplosis sorghicola, is a devastating pest of flowering grain sorghum but also coexists on Johnsongrass. This little fly, about the size of a gnat, is orange-red in color and has a unique biology. The midge lives less than 1 day but during that time a female can lay approximately 50 eggs. She will deposit only one egg in one of the flowering spikelets. The next day another brood of adults emerges from nearby Johnsongrass or other previously infested sorghum fields to deposit eggs in new flowering spikelets. So, depending on an individual flowering head it may be vulnerable to egg lay for 7 to 9 days and individual fields for 2 to 3 weeks.

Each of egg infested spikelet will have a midge larvae hatch in it in 2 to 3 days. The larva consumes the newly fertilized ovary resulting in the spikelet not developing a kernel. Depending on the number of sorghum midge present during the flowering period a portion of destroyed spikelets may be scattered among normal kernels or a majority of spikelets may not develop kernels. Insecticides are ineffective at controlling midge larvae once spikelets are infested.

Scouting fields during the flowering period is critical to knowing if insecticide applications are needed to kill adults before they have a chance to lay eggs. The residue from an insecticide application should provide midge suppression for 1 to 2 days after treatment. If adults are still found 3 to 5 days after the first application, immediately apply a second application.

The time to check flowering fields for midge is when temperatures are around 85o F. This could be mid-morning in some areas or afternoon in other areas. Adjusting the time to scout based on the temperature is important because midge are not active during lower temperatures.

Currently, midge activity is relatively low in the Lower Rio Grande Valley, according to Dr. Raul Villanueva, Extension Entomologist. Dr. Robert Bowling, Extension Entomologist, Corpus Christi, reports grain sorghum fields were late planted due to rains and are at least 2 weeks from flowering. Late planted fields in the Blacklands and north Texas regions may also be vulnerable to midge when fields begin to flower, notes Dr. Allen Knutson, Extension Entomologist, Dallas. Rains across the other areas of the state may have delayed grain sorghum planting and could influence midge infestations later in the growing season.

More detailed information about the sorghum midge can be accessed here.

/* = '9' ){ jQuey('h1,h2,h3,.additioal_posts_module h4,h4,h5,.logo a,.call_to_actio,#ito .ito_title,#ito .tease,#slide_module+#ito h3,#sideba .widgettitle,#outo,#outo a,#foote .widgettitle,.toggle a,.toggle_accodio a,#cotet .tease').css('opacity', '1'); }else if(!ua.msie){ jQuey('h1,h2,h3,.additioal_posts_module h4,h4,h5,.logo a,.call_to_actio,#ito .ito_title,#ito .tease,#slide_module+#ito h3,#sideba .widgettitle,#outo,#outo a,#foote .widgettitle,.toggle a,.toggle_accodio a,#cotet .tease').css('opacity', '1'); }} /* ]]> */