Atherigona reversura calls Japan, Indonesia, India and even Hawaii home. But it is damaging hay fields in south Georgia and north Florida, and there's little growers can do to stop it right now.
This invasive fly lays eggs in bermudgrass stalks, and its maggot bores down the stalk, killing the first two to three leaves. Bermudagrass is an important crop grown from North Carolina to Texas as a pasture grass or for hay. This type of grass seems to be the most damaged by the fly, particularly the finer textured and most widely planted bermudagrass varieties Coastal and Alicia.
Unfortunately, killing the Asian fly's larvae is difficult. The growth habit of this insect means that a successful insecticide application would likely require a systemic mode of action, said Dennis Hancock, University of Georgia Cooperative Extension forage specialist. Systemic insecticides are generally not approved in forage production.
Harvest management is the only option to limit the damage to hay, he said. If damage is found within 1 week of the normal harvest stage, it's best to harvest the crop as soon as weather conditions allow because the crop is unlikely to add a significant amount of yield.
If damage is seen 1 to 3 weeks after the previous hay harvest, it is also likely that the crop will not add a significant amount of yield. The damaged crop should be cut and (if the yields are substantial enough to warrant) baled and removed from the field as soon as weather conditions allow. Leaving the damaged crop in the field will only compete with any attempts by the plant to regrow and decrease the opportunity that the next cutting will have to accumulate mass.