Michael Gray Email

On August 26, Joe Spencer an entomologist with the Illinois Natural History Survey, and I traveled to Livingston and Kankakee counties and confirmed significant western corn rootworm larval injury in first-year cornfields that had been planted to Bt rootworm hybrids (VT Triple PRO RIB – expresses the Cry3Bb1 protein). The fields in question were brought to our attention by Bryan Johnston, Cabery Fertilizer, Cabery, Illinois. Bryan indicated that many first-year Bt cornfields in the area had severe root pruning and lodging.…

Recently, statewide surveys of insects in corn and soybean fields were conducted in 28 counties across Illinois. The surveys were performed by sampling five corn and five soybean fields (randomly selected) per county during two periods (August 1 through 6, and August 14 through 16). In each cornfield, 20 consecutive plants were examined for western corn rootworm adults. In soybeans, 100 sweeps were taken (at least 12 rows from the field edge) per field. Densities of western corn rootworm adults exceeded the 0.75 per plant (continuous corn) or 0.5 per plant (first-year corn) beetle thresholds during the August 1 to August 6 time frame in the following counties: Christian (0.91 adults per plant),…

On the morning of August 12, Russ Higgins, University of Illinois Extension Commercial Agriculture Educator, Northern Illinois Agronomy Research Center, sampled soybean fields in DeKalb, Grundy, Kendall, and LaSalle counties. In four of seven commercial soybean fields, he detected soybean aphids in low numbers. Typically, Russ found one to two aphids per leaf. He also noted that beneficial insects were abundant within the soybean fields.
The economic threshold for soybean aphids remains at 250 aphids per plant with 80% of plants infested. …

Although western corn rootworm adult emergence is underway across many central Illinois counties, a quick poll of participants at the DeKalb Research and Education Center field day near Shabbona, Illinois on July 10 revealed that participants have not observed any beetles moving about their cornfields. Joe Spencer, an entomologist with the Illinois Natural History Survey, observed larvae continuing their root feeding activity in his research plots north of Urbana on July 9. Based upon these observations,…

Western corn rootworm adult emergence is underway across east central Illinois. On July 1, Nick Tinsley, Research Specialist in the Department of Crop Sciences, observed his first adult male western corn rootworm of the growing season just south of Urbana within a University of Illinois research plot. Later that day, Joe Spencer, Associate Research Professor, Illinois Natural History Survey, observed five western corn rootworm adults after about 20 minutes of searching in his research plots north of Urbana.…

Reports of Japanese beetles are becoming more common across the state of Illinois. On June 19, Ron Hines observed his first Japanese beetles of the season in Massac County. Much further to the north, Angie Peltier, University of Illinois Extension Commercial Agriculture Educator located at the Research and Demonstration Center, Monmouth, Illinois, collected about 1 inch of beetles in a trap from June 20 to 24. These observations confirm that this perennial insect pest of corn and soybeans is present throughout much of  the state.…

In mid-June, Chris DiFonzo, Extension Entomologist at Michigan State University, reported that a soybean field (Saginaw Farm) was infested with soybean aphids (~44% of plants infested).  Chris indicated that none of the plants had received an insecticidal seed treatment. Reports from other entomologists (Iowa and Minnesota) indicate that soybean aphids are being found at more modest levels. At this point, it remains unclear what soybean aphid infestations will look like for much of the Corn Belt.…