Same old story. . . . Black cutworm moths continue to fly throughout the state, but flights are significantly lower in northern Illinois. Regardless of these flights, cornfields should be scouted for early cutworm injury. A few more reports this week indicated some small feeding has been seen on seedling corn. Refer to earlier issues of the Bulletin for tips on scouting (issue no. 5, April 25, 2003) and rescue treatments (issue no. 6, May 2, 2003).
Second verse same as the first. . . . According to degree-days posted in last week's Bulletin (issue no. 7, May 9, 2003), most of the state of Illinois should be experiencing larval feeding. Overall, alfalfa weevil injury is fairly scattered this year, but reports are still trickling in. A few more e-mails made their way in last week, but little more than pinhole feeding was reported. Reports of economic damage are few and far between; we received a few calls indicating some fields were being treated. As we progress past the first cuttings, injury to regrowing buds is minimal. But, as a reminder, control may be warranted after a cutting when both larvae and adults are feeding on more than 50% of the crowns and regrowth is prevented for 3 to 6 days.
Something new. . . . Potato leafhoppers are here! As the alfalfa weevil season winds down, get ready for potato leafhopper activity to begin. Potato leafhoppers do not overwinter in Illinois. These small green insects "ride" in on winds from the southern states. They are not a threat at the current time. Generally, potato leafhoppers do not increase to damaging levels until after the first cutting, the time scouting should begin. Economic levels of injury may be caused and treatment required when 0.2 leafhopper is found per sweep on alfalfa zero to 3 inches tall and when 0.5 leafhopper is collected per sweep in alfalfa 3 to 6 inches tall. More information on the insect in future newsletters. . . .
As always, I'm interested in anything you might find in the field.--Kelly Cook