NEWS & UPDATES
Agricultural Research Service, USDA, ars.usda.gov
While army worms have natural predators in the southern U.S where they are commonly found, these predators cannot withstand the cold climate of northern states. The moths migrate north each spring to lay eggs, leaving behind their predators and taking on invasive characteristics. These moths have landed early this year due to earlier than normal warm temperatures. They have landed in New York- first hitting the western part of the state and then traveled to the Finger Lakes region and now parts of eastern New York. While the armyworms will not be able to overwinter in the cool climate of New York, they still pose a threat to agricultural crops while they remain here in the warm summer months.
How to Identify them:
Armyworms can be identified at several stages in their life cycle. The larval stage is the stage that causes the most damage. The egg sac is dome shaped and holds between 100-200 eggs. In between each egg and coating, the entire outside of the dome are scales that give it a furry, moldy look. The eggs are most often laid in a single layer. The pupa forms a loose cocoon and stay in the dirt until they hatch. The larva is purple to reddish brown or green in color and has a striped pattern. They are between 1-1.5 inches in length. The adult moths of armyworm are nocturnal. They have a wing span that is about 1.5 inches. Their wings are colored brown and gray or a molting of brown and white. Males will have distinctive patterning of triangles on their top wing.
Left to Right Egg(USDA, usda.gov), larva(USDA, usda.gov), adult female and adult male ( John L. Capinera, University of Florida)
Why They are so Terrible:
The most damaging stage of the armyworm is the larva. This stage feeds on the leaves of plants such as grass and many agricultural crops such as corn, legumes, cabbage and cucumbers. The larva lives in the dirt and then migrates upwards into the plant. Once an area has been completely eaten, the worms migrate in a group to a new area, hence the name armyworm. They usually feed at night and can go unnoticed before they cause a substantial amount of damage to a crop field. This can cause farmers to lose most or all of their crop, and have severe economic impacts on agricultural communities.
(Corn infested with armyworms) USDA, usda.gov
How to Control it:
Monitoring and early detection of armyworm is very important because the worms move at a rapid pace and can migrate across an entire field. They are not easily spotted during the day since they are nocturnal feeders and will curl up and hide during the day. If these pests are found it is important to treat them right away with a pyrethoid class pesticide. Pesticide use can be kept to a minimum by spraying a buffer zone around the infected area. Early treatment with pesticide is generally very effective. In addition to pesticide use integrated pest management can also be used to protect fields from future infestations of armyworm as well as other pests.
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