Sorghum Midge

Insecticide application is needed when the infestation is very severe. This can be identified by observing the number of midge flies on sorghum earheads. When 2 to 3 midge flies are found, then spray the insecticide on the earheads when 90% of the heads have emerged in the field. Insecticides such as Carbaryl 50SP (3 kg in 500 L water/ha), or Endosulfan 4D or Carbaryl 3D (20 kg/ha), and can effectively check the midge infestation.

The adult is a tiny fly with a yellow head, brown antennae and legs, an orange-red thorax and abdomen, and grayish hyaline wings.

The fly can be seen hovering around the earhead during early hours of the day. Each female lays about 75 eggs in flowering spikelets during its short span of 1-day life. An orange colored maggot hatches from the eggs in 1 to 3 days, and start feeding on the contents of the fertilized ovary. The insect's rapid developmental cycle permits 9-12 generations to occur during one season.

High infestations build-up when sorghum flowering times are extended by a wide range of planting dates or maturities. The presence of midge flies can be identified by visiting the sorghum field early in the morning or late in the evening when the flies are active hovering the flowering panicles. Midge infestation can be identified from the red ooze that comes out when the developing seed in the spikelets are pressed with fingers.

Crop damage: Despite the fact that adult sorghum midge live less than 1 day, midge is capable of causing significant grain loss, as it is the larvae that feed on newly fertilized ovaries preventing seed development. A sorghum panicle infested with sorghum midge will have, depending on the degree of damage, varying proportions of normal seed and non-seed bearing spikelets. Under severe infestation the entire earhead looks blasted with chaffy head appearance

Management: The first choice of management should be early and uniform sowing of similar maturity sorghum cultivars over large areas. Destruction of wild host plants including Johnson grass and sorghum volunteers early during the season may slow midge population development. Growing grain sorghum varieties and hybrids, like SPH 837, possessing some level of resistance to sorghum midge.