|By TIM ALEXANDER
URBANA, Ill. — Entomologists with the University of Illinois (UOI) Extension convened with colleagues across the Midwest during an information-sharing teleconference on July 18.
The topic: insect situations and issues in their respective states. The Extension provided a synopsis of pest problems discussed by UOI entomologists Kevin Steffey and Mike Gray during the teleconference.
“Large numbers” of reports of western corn rootworm adults in some areas, along with “extensive” rootworm larval damage in some fields.
Corn and soybean fields continue to be plagued by Japanese beetles. According to an article posted by Steffey and Gray on July 14 in the Bulletin, Japanese beetles have “captured the most attention” of the state’s farmers in 2006, with “their huge numbers diverting some attention from rootworms.”
A report of large numbers of woolybear caterpillars clipping silks in a cornfield in Iroquois County. Woolybears have been known to cause significant defoliation of soybean plants.
Low numbers of soybean aphids are present in “many fields.”
The pair also revealed that Kevin Black, entomology and plant pathology specialist with Growmark in Bloomington, reports numbers of bean leaf beetles in southern Illinois fields are larger than he has observed in recent years, though still below threshold levels. Virus infection was evident in some of the fields. Black also warned that numbers of green stink bugs (adults, nymphs and eggs) are “large” in some soybean fields in southern and western Illinois. Green stink bugs can cause significant yield losses when they feed on soybean pods.
A weekly survey of soybean fields in Woodford and Stephenson counties conducted by the UOI continued to reveal small numbers of soybean aphids, though numbers have recently increased in Stephenson Co.
“These numbers of soybean aphids are way, way below the threshold of 250 aphids per plant, but the increasing numbers bear watching,” Steffey said. “Development of soybean aphid populations slows down or declines when temperatures exceed ninety degrees, but a return to gentler temperatures will benefit population buildup.”