The Army Has Arrived on Vermont Farms!

Guest blog post from Heather Darby, an Agronomic and Soils Specialist for the University of Vermont Extension. Being raised on a dairy farm in Northwest Vermont, has also allowed her to play an active role in all aspects of dairy farming  as well as gain knowledge of the land and create an awareness of the hard work and dedication required to operate a farm.  Heather is involved with implementing many research and outreach programs in the areas of fuel, forage, and grain production systems in New England. 

Well, not in the traditional sense, but for the last week armyworms have decimated many corn and hay fields in northern Vermont.  The armyworms, the caterpillar life stage of a moth, are living up to their names, marching across fields, and even over roads to get their next meal.

Why are these pests making a mess in the area? Remember the luxury of not having to shovel snow this past winter? Oh and yes the 80-degree warmth in March? Well, mild winters and unusually warm spring conditions throughout the country have led to the early outbreak of this insect pest.

Armywom survives the winter in the southern U.S. The moths hatch in the spring and fly long distances in large swarms migrating northward. Armyworm moth migrations are somewhat sporadic, cyclic from year to year and difficult to predict. Each year there is usually a mild and often isolated outbreak in the area. However, this season the infestation is of high populations and across a broader area. Once the moths land they lay their eggs on grasses, on leaves of corn, or on small grains. Larvae hatch about a week later and develop over approximately a 3-week period, feeding mostly at night.

The caterpillars that I have seen are mixed sizes; meaning adult moths came in on several different weather fronts. This will and has extended the time armyworm will feed in fields. I am observing some biological control as over 60 wasps and fly parasitoids infect armyworm, along with pathogens that help control the population. These biological control mechanisms will help reduce the chance of a second-generation outbreak.

Damage has been severe on many farms and in some cases has resulted in the complete loss of crops. A farmer told me that there were so many armyworms in the field that it felt like the ground was moving. Once they completely devoured the 40-acre corn field they were seen marching into a neighboring 80-acre field.  This same farm also had 100 acres of hay heavily infested with armyworm. Luckily they were able to harvest the hay before the armyworms ate everything! Another farmer worked several 24-hour days to stay in the front of the armyworms. Everyday the hay fields were scouted and the worst fields were harvested.  The long hours paid off, as they did not lose any of the crops. Many other farms were impacted and have had to replant hundreds of acres of corn.

Many farmers are asking why are we seeing so many pests? One farmer old me that “we never use to have a problem with armyworms and now it seems like every year the problem seems to get worse”. Is this a sign of what is to come as the climate changes and mild winters become a norm for many areas. Will pest populations and outbreaks continue to present major challenges to the farming community? Another farmer told me “that it is just getting harder to farm!”

View video of Heather discussing the army worm attack on WCAX-TV, Vermont’s local CBS affiliate.


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