A scouting calendar can be helpful when searching fields for potential threats. Another source of information, possibly even more accurate than the calendar, can be established by word of mouth.
Agronomist Danny Greene, Greene Crop Consulting in Franklin, warns farmers of fall armyworms, which are currently en route to Indiana in swarms from Kentucky.
The moths of these worms are dark gray with splotches and distinct white spots on the ends. They are attracted to late planted corn, where they lay eggs for larva hatching. These larvae are green or black and have dark stripes. When looking for these pests, look for the coloring as well as the looping motion in which they move.
The fall armyworm larvae feed on corn leaves and attack the tassel and ears. The damage resembles ragged holes on the plant, somewhat like hail damage on the most affected, according to Purdue University Extension.
To scout for fall armyworms, look for the damage that the larva caused and eggs laid by moths. Sampling should be conducted in at least five areas within a field. In each area, pick a random row of 20 consecutive plants. Next, determine the number of plants damaged in the group. From the damaged plants number, figure the percentage of infected plants. Another useful tool is to note the number of larvae and their size.
Related: Scout For Armyworm To Save Yields
Although one should always keep a close eye for all armyworms, the application of insecticide is usually not economical for control, unless substantial damages are done. Treatment is encouraged when the infestation reaches 75% or greater, with larvae fewer than 1.25 inches long and significant plant stress.
If certain locations in a field are affected, spot treatments can be used to manage infestation.
My daughter, Casey, a crop scout with Greene Crop Consulting says she hasn't seen any fall armyworm damage yet this year in fields. "But the threat is there as these swarms of moths make their way north," she says.
The opinions of Jennifer Campbell are not necessarily those of Indiana Prairie Farmer or the Penton Farm Progress Group.