Matt Rundle, an NK agronomist for Syngenta, was surprised to see the amount of FAW pressure this year.
“The fall armyworm is typically not a pest we deal with in large numbers, but this season, a large population of moths arrived in Ontario, migrating up from the southern US,” he explains. “Those moths have mated, and now their larval offspring are wreaking havoc, particularly in our hay and forage cover crops in South/West Ontario. They are being found in patches, but as their name suggests, they can move through a crop and destroy in a short period of time.”
Different from the true armyworm, FAW will attack broad-leaved forages like alfalfa in addition to small grains and corn, he added.
“In corn, late planted fields are at most risk. The moths are attracted to them as they know it will provide their offspring with a food source for the longest time possible, he said. “In small grains, cover crops and forages, the armyworm moths are attracted to thick, lush canopies. Areas of the field with planter overlap are a great place to start scouting.”
Control options depend on the size of FAW in the field, Rundle said. The Agrisure Viptera trait also controls FAW.
“In forage cover crops, early cutting is an option,” he adds.
“In hay, the conversations get really tricky because we are past the critical fall resting period for some areas of the province,” he explains. “We do not want to cut the hay crop too late and risk overwintering damage to the alfalfa crowns. This requires an in-depth discussion considering factors such as how long the field is intended to be in hay, the pressure of the fall armyworm, and the number of acres it is affecting.”
FAW are a migratory pest, and will not survive winter, he adds. Regular scouting is key to staying on top of this pest for the remainder of the season.
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