Fall Armyworm, Spodoptera frugiperda.
Fall armyworm egg mass.
Late instar larva showing distinctive net pattern and inverted 'Y' on head.
This moth is an annual pest from southern states. Arriving in Kansas in July, it lays eggs on corn, sorghum and other summer crops. Damage to sorghum may occur from July to the first frost. Feeding during the whorl stages causes large, irregular perforations in the foliage that are evident as leaves unfold, giving the plant a ragged appearance. Late-planted fields may suffer more damage if attacked while the plants are small.
Leaf damage has little effect on yield, and larvae feeding within the whorl are protected from exposure to insecticides, making control difficult at this stage. Do not consider treatment unless 75 percent of plants show fresh damage and there are one or two live larvae per plant. Head infestations by fall armyworm and mixed infestations with corn earworm can be assessed the same as for corn earworm.
Please refer to the most recent version of the Sorghum Insect Management Guide for specific control recommendations.
Page last updated on 10/31/2013 by J.P. Michaud.