Serious infestations of sorghum midge are relatively uncommon in Tennessee, but they can be very damaging. Sorghum midge is a small, gnat-like insect that is reddish-orange and about 1/10-inch long. Female sorghum midges lay eggs only during the bloom stage. Eggs are laid in the spikelets between the glumes of a floret. The larvae feed on the developing seeds, causing them to dry up and die.
Once grain heads are present, check for sorghum midge throughout bloom every 4-5 days. You can visually look for the reddish-orange flies, but a preferred method is to place a clear plastic bag over the head and shake, looking for midges that land on the plastic. Examine a minimum of 50 heads field in randomly selected areas of the field.
During flowering, once 20-30% of heads are blooming, treat when an average of one midge is found per head. More than one treatment may be needed in some cases.
|Insecticide (Trade Names) for SORGHUM MIDGE||Lb Active Ingredient per Acre||Amount Formulation per Acre||Performance Rating|
|chlorpyrifos (Lorsban 4, Nufos 4)||0.25||8 oz||6|
|chlorpyrifos (Lorsban Advanced 3.775)||0.24||8 oz||6|
|chlorpyrifos, γ-cyhalothrin (Cobalt Advanced)||See label||6 - 13 oz||8|
|chlorpyrifos, Z-cypermethrin (Stallion)||See label||3.75 - 11.75 oz||8|
|methomyl (Lannate LV 2.4)||0.225 - 0.45||12 - 24 oz||6|
|esfenvalerate (Asana XL 0.66)||0.015 - 0.03||2.9 - 5.8 oz||8|
|spinosad (Blackhawk 36% WDG), suppression||0.034 - 0.074||1.5 - 3.3 oz||5?|
|β-cyfluthrin (Baythroid XL 1)||0.008 - 0.01||1 - 1.3 oz||8|
|γ-cyhalothrin (Declare 1.25)||0.0075 - 0.01||0.77 - 1.02 oz||8|
|λ-cyhalothrin (Warrior II 2.08)||0.015 - 0.02||0.92 - 1.23 oz||8|
|Z-cypermethrin (Mustang Max 0.8)||0.008 - 0.025||1.28 - 4 oz||8|
- Insecticide applications are made to control adults and prevents egg laying because larvae are hidden from insecticides.
- Planting early, before mid-May, may help avoid some damage from sorghum midge.
- Sorghum midge are often worse in sorghum next to earlier maturating fields that serve as a source of infestations.
- Johnsongrass is an alternative host that may serve as a nursery for sorghum midge. Maintaining good weed control in and around a field can reduce infestations.