Corn Borer Moth Flight Has Started

Light traps in Dell Rapids and Sioux Falls have both registered catches
of corn borer moths starting on the night of June 5.

The light trap in Sioux Falls is located on my deck while the Dell Rapids
trap is in the backyard of Steve Munk's home.

Compared to last year's flight, the moths are about 2 weeks "late."

The light trap at UNL-NEREC in Concord, Nebraska is also showing 5 moths caught
on June 6.

As of today (6-7-01), we have not found any corn borer moths yet north of
Dell Rapids. The univoltine ecotype is found north of Dell Rapids. 

Black Cutworms Significant in Southeastern Counties

Corn seedlings may be vulnerable to cutworm damage in southeastern SD.
Corn growers are encouraged to inspect their fields as soon as possible.

Approximately 900 acres of corn seedlings have already been sprayed
for cutworms in Union County as of June 1, according to Agronomy
Educator John Gille, with most of the affected areas close to Iowa.

Crop consultant Larry Sax reported on May 30 significant cutworm
activities in about 400 acres of corn in Minnehaha and Lincoln counties.
Black cutworms caused most of the damage on the corn seedlings,
according to Larry.

I also received a report from Yankton County, and personally inspected
fields in Clay County.

Cutworms are active at night and hide under loose soil during the day.
Scouting during the day involves scratching the soil surface to expose
hidden larvae.

Insecticide treatment may be considered if 5% (1 in 20 seedlings)
of the seedlings show signs of cutting or leaf feeding and the larvae
still less than an inch long.

Insecticides labeled for use on corn to control cutworms include
Ambush 2E, Asana XL, Lorsban 4E, Pounce 3.2EC and Warrior.
Read and follow all directions on the label.

Two species of cutworms commonly infest corn seedlings in SD.
Dingy cutworms overwinter as partially grown larvae in the soil then
resume feeding in the spring.  Black cutworms arrive in the field as
moths then lay eggs on weedy and wet fields in the spring.
Larvae of black cutworms are more damaging because they cut the
corn growing points from under the soil.  In general, cutworm infestations
are more common in fields with more plant residues, weeds, and moisture.

Web posted on June 7, 2001 by Mike Catangui

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