Released April 14, 2009
MANHATTAN, Kan. – “Cutworm” is the generic name for the caterpillars (larvae) of about 2,900 kinds of nocturnal moths, commonly known as millers. All fell tender green plants like a North Woods logger.
The larvae start feeding in early spring. Many species have a second, sometimes much larger generation later in summer, said Bob Bauernfeind, Kansas State University Research and Extension entomologist.
“Fortunately, only a few species can create economic problems in our region’s field crops,” Bauernfeind said. “Many more can attack gardens, but homeowners don’t need to identify species. Gardeners typically control cutworms by hand. And, the insecticides labeled for home use simply list the pest as ‘cutworms.’”
No matter their species, mature cutworms can be 1.75 inches long. They all look similar – plump, fleshy, smooth and sparsely haired, he said. But, they hide during the day and feed at night. So, gardeners’ first clue that cutworms are on the attack is often a bedding plant, cut off at ground level and lying on its side.
“That kind of discovery can be very discouraging,” Bauernfeind said. “We’re just lucky that we don’t have more gardeners who see some degree of cutworm damage almost every year.”
Depending on species, the night-flying adult moths emerge from April to July. They’re the many dull-colored miller moths that for several weeks each year swarm any light source they can sight, he said.
Before the adults die, each female may lay up to 500 eggs. Many deposit eggs where they happen to be resting, almost ensuring their new larvae will have to search for the plant food they need. But, some moth species selectively deposit eggs on the exact host plant their offspring will need to survive.
“Cutworms have a host of natural enemies, though, ranging from little parasitic wasps and certain viruses to blackbirds, toads and various foraging mammals,” Bauernfeind said. “So, in most cases, the cause of garden damage turns out to be just one or two caterpillars.”
The culprits are easy to find, he said. They hide next to cut plants, just under the surface soil, mulch or garden debris. Gardeners can simply forage around, pick the caterpillars up and dispose of them. But, as a precaution, they may also want to protect nearby plants with a stem wrap of aluminum foil.
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http://www.oznet.ksu.edu/news/story/briefs041609.aspx
Contact: Elaine Edwards, elainee@ksu.edu
