By JARED ORZOLEK

orzolek@crescent-news.com

An insect has invaded northwest Ohio in recent weeks, targeting farmers' wheat and corn crops, local agriculture experts say.

Armyworms -- known for their ability to march from field to field or over roadways in search of green plants to eat -- have recently been seen in high numbers in fields in area counties.

"We have probably fielded 30 to 40 questions on armyworms this week," said Glen Arnold, agriculture agent with the Putnam County Ohio State University Extension Office.

"Now they are hatching and causing concern for farmers. The armyworm likes grasses. They also like wheat and they also like corn."

Agriculture experts report that adult armyworm moths arrived in northwest Ohio in April and May. Carried by weather systems, the moths fly north from southern

states like Kentucky and lay eggs in fields or clusters of grass.

When the eggs hatch, the larval worms eat green vegetation until they reach close to an inch and a half in length. They then enter a pupation stage and adult moths emerge in one or two weeks.

The insects are only dangerous to crops during their larval worm stage. The worms are seen in northwest Ohio annually, but farmers are dealing with above average numbers of the insects this year.

"We are seeing a large number of moths that came up from the southern states into Ohio," Arnold said, explaining that agriculture experts in Kentucky observed high numbers of the moths earlier this year.

The worms consume plants like corn, wheat, or grasses planted in ditches, but do not typically target soybeans or alfalfa.

"The numbers vary from field to field," Arnold said.

Jim Lopshire, agriculture agent for the Paulding County Extension Office, said armyworms reach densities high enough to warrant a pesticide application when farmers observe five to six insects per foot of plant row.

"We have received some reports of armyworms out there to the point where it becomes cost-effective to spray," Lopshire said.

"We are seeing damage in some cases where all the leaves have been removed or eaten. It's definitely widespread and basically covers the northern half of the state."

Lopshire said pesticides can be applied by airplane, helicopter or ground applicator and said 2008 marks the second year in the last seven when infestations have reached levels that require pesticide applications.

Lopshire said armyworms do not become active until evening, so farmers must scout their fields for the insects during the appropriate time.

"It's good to see farmers out scouting their fields. You don't want to lose that yield potential," Lopshire said.

"If you walk the fields during the day you won't see that many of them -- if any."

The insects have also been observed in Henry County, according to an official at a grain elevator located in the southwestern portion of the county.

"It's causing quite a bit of economic damage," said Gary Pennell of Farmers' Elevator in Pleasant Bend, which provides pesticide application services as well as grain storage.

"We have really been spraying a lot of these. We need to continue looking for the worms for a week to 10 days. Normally, it's just a field or two. This is the most widespread I have ever seen them."

Armyworms are known for their ability to march en-masse from one field to another. They sometimes march across a roadway and are capable of eating an entire lawn in one night.

"Homeowners tell me it's a weird feeling to wake up and find your lawn missing," Arnold said.