These parasites and other beneficial organisms usually keep armyworms from reaching damaging levels. Avoid treating with insecticides when large numbers of parasitized larvae are present. Before deciding whether or not to treat for armyworms with an insecticide there are a few things to consider. First, what sizes are the armyworms. Controlling larvae of this size is not profitable because the damage is already done.
Pheromone traps are available to monitor adult armyworm activity.
See ENT-54, Vendors of Microbial and Botanical Insecticides and Insect Monitoring Devices , for a list of vendors of the armyworm lures. Armyworm moths are common throughout the season and are frequently captured in pheromone traps baited for other moth species. Control Preventive treatments for armyworms are not justified. Although it may appear as if the preventive treatments are very effective and that some fields in Kentucky that have significant armyworm infestations will require treatment, in fact the likelihood that a particular field will have an outbreak of armyworms is still very small and is usually associated with a regime of no-till into grassy cover crops. Keep in mind that majority of fields will have some armyworms in most years, but the chance of encountering a infestation that economically justifies the cost of treatment is small on a field by field basis.