Texas Grain Sorghum: Early Fields Reaching Midge Scouting Period
Earlier fields of sorghum are heading and beginning to bloom. So, it is time to start looking for sorghum midge on the field margins.
The adult sorghum midge is a small (less than 1/8 inch), orange-red fly with a yellow head, brown antennae and legs and gray, membranous wings.
Scout fields in the morning when the temperature warms to approximately 85° F. Because adult sorghum midges live less than 1 day, each day a new brood of adults emerges. Sampling must be done almost daily during the time sorghum grain heads are flowering.
Sorghum midge adults can be seen crawling on or flying about flowering sorghum grain heads. The simplest and most efficient way to detect and count sorghum midges is to inspect carefully and at close range all sides of randomly selected flowering grain heads.
Inspect plants along field borders first; particularly those downwind of earlier flowering sorghum or johnsongrass. If no, or few, sorghum midges are found on sorghum grain heads along field edges, there should be little need to sample the entire field. If you find more than one sorghum midge per flowering grain head in border areas of a sorghum field, inspect the rest of the field. Sample at least 20 flowering grain heads for every 20 acres in a field.
For fields smaller than 20 acres, sample 40 flowering grain heads.
Sorghum Headworm Calculator: We have added a calculator to the Entomology Website to calculate the economic threshold of sorghum headworms. We are hoping to add midge and stinkbugs to this calculator soon. https://insects.tamu.edu/extension/apps/sorghumheadwormcalculator/
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