Just about every year, we will get reports of True
Armyworm, Pseudaletia unipuncta,
damage somewhere in the state. Some years, like in 2001 or 2007,
we can have severe outbreaks across a wide region. In most years,
there will be isolated cases but even those can be significant to the
farm affected. Crops most affected are grasses including
field corn, grass hay and pasture crops.
It is important for farmers and consultants to be
monitoring fields starting in mid-June. At a high enough
population, armyworms can create a lot of damage very quickly.
One comment I got from a farmer in 2007 went something
like this, "We looked one day and saw a little damage, but when we
couple days later many of the plants were totally stripped!"
If you detect a problem, try to assess the severity of the damage as well as the age/size and population of the larvae. Spraying with an insecticide is expensive and may not be necessary (or too late).
The best time to look for the larvae is very early in the
morning or just before dark. Armyworm larvae tend to stay near
the soil surface during the day when it is hot and feed at night.
For more information refer to the links and factsheets below:
Outbreaks of Armyworm in 2012
Insecticide Control Options from the VT Agency of Agriculture
Armyworm - Here We Go Again in 2007
Recovery of Field Corn, Haycrops, and Pasture Following Armyworm Damage
you detect armyworm in your field crops or forages or have any questions contact Jeff Carter, Dan Hudson, Heather Darby or Sid Bosworth.
you have armyworm damage, please email me and give me your name, phone
number, crop(s) affected, acres, and extent of damage. Sid.Bosworth@uvm.edu
This site is maintained by Sid.Bosworth@uvm.edu,
Plant & Soil Science Department, University of Vermont.
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