New Insecticide For Fall Armyworm Control in Pastures and Hayfields

By: Lynn Stillwell Sampson County Livestock Agent

The Fall Armyworm, is a chronic pest here in NC and the rest of the Southeast. It feeds on many forage crops, but appears to prefer a lush healthy stand of Bermudagrass that we grow so abundantly here in Sampson County. The Fall Armyworm prefers many of common winter annuals grown here such as Rye, Wheat and Oats. Those who have had armyworms attack their pastures and hayfields know how devastating it can be and how much damage the one and half-inch long larva can cause.

These pests, as their name implies, are most numerous late summer to early fall. Damage can typically be seen during the months of August through October,. However in times of drought (such as now) it is not uncommon to have an outbreak in July, this is because natural enemies of the armyworm are less effective during drought. Scouting your pastures and hayfields can help identify infestations before significant and economic damage is caused. An easy sign is the presence of flocks of birds feeding in your fields or pastures. Armyworms are most active in the early morning or late afternoon.

If you have determined you have an infestation in your pasture or hayfield you have always had several insecticides to choose from. As of earlier this year you have one more method of control. Prevathon^R insecticide by Dupont has now been registered in NC for use in pastures (as well as corn and cotton) for Fall Armyworm control as well as budworms and bollworms. The active ingredient is RynaxypyrÒ. It is a foliar treatment in all types of pastures from Bermudagrass to fescue as well as any cereal grains to be grazed. This is a non-restricted use insecticide. Animals can graze immediately after application, although there is a four-hour worker re-entry period. With Fall Armyworms soon to be marching across our fields, there is now one more weapon that offers a solution to their destruction.