Wheat stem sawfly and western bean cutworm are pests that have caused concern throughout the growing season in the Panhandle this year. Sugarcane aphids are still in Kansas, but they are knocking at the border. We talked with University of Nebraska Extension entomologist Jeff Bradshaw recently to get an update on the pests that were of concern for producers in the Panhandle this season. These are the pests that were on Bradshaw's radar.

NOT WHAT YOU WANT TO SEE: Although blackbirds appear to have cleaned this ear of corn from WBC larvae, they also peeled back the husk and damaged the ear.

Western bean cutworm
Western bean cutworm hits both corn and dry beans in the Panhandle. "We saw a large number and an extended flight of WBC this year," says Bradshaw. "In corn, there are some Bt hybrids that are still effective in managing WBC," he says. "In at least one field this year, I witnessed a scenario where birds had picked a number of larvae from corn ears by stripping back the husk and pecking out the larvae." Bradshaw observes that this is a unique example of biological control, but it is probably a scenario most producers would like to avoid.

"It might be better to avoid having your corn kernels exposed and pecked in this way," he says. "Early scouting and proper timing of insecticide applications are warranted in corn fields that are not protected by Bt."

ON THE LOOKOUT: University of Nebraska Extension entomologist Jeff Bradshaw examines dry bean plots at the Panhandle Research and Extension Center at Scottsbluff. Bradshaw, along with other entomologists, growers and crop scouts, has been on the lookout this past summer for several pests of interest.

In dry beans, insecticides are really the only tools available. "Dry beans are very difficult to scout for WBC because the bean canopy is often closed over by the time one needs to scout," Bradshaw explains. "Pheromone traps or blacklight traps can provide an indication of the size of the population, but they have not been shown to be very reliable for finding an action threshold." By late August in this season, Bradshaw reported that growers were already seeing WBC feeding on dry bean pods. "It only takes two or more larvae per foot of row to indicate a need for action," he says.

Wheat stem sawfly
Wheat stem sawfly infestations were somewhat spotty this season. "We are still gathering data now from our summer survey from wheat fields for the wheat stem sawfly," says Bradshaw. "Indications were that some locations saw high numbers of sawfly, which in some cases, resulted in significant lodging." A number of the fields hit hardest were in the southern Panhandle, Bradshaw says. "However, there might be some good news. Last year we found large numbers of parasitoid that attacks wheat stem sawfly in a few field locations in the northern Panhandle," he explains. "It seems that this beneficial insect has been increasing in numbers and may have dropped the survival of sawflies to nearly zero in a couple locations. We will be conducting some research that is supported by the Nebraska Wheat Board to try to understand why and how this parasitoid has become so effective in a few fields." Bradshaw hopes there may be a way to conserve the activity of this sawfly killer through proper management practices.

Sugarcane aphid
Sugarcane aphid is another pest that keeps entomologists on the lookout. Although not yet found in Nebraska fields, sugarcane aphid appears to be working north through Kansas sorghum fields. "This is a newly invasive insect that is of chief concern for our sorghum growers," Bradshaw says. "Current reports from states to the south seem to indicate that the geographic spread of this insect has been slower this year than in the previous two years. However, some reports indicate that populations of this insect are intensifying in western Kansas." Vigilance on the part of growers, crop consultants and scouts and Extension entomologists will be required to track the progress very closely, he says.

You can learn more about insect pests in Panhandle crops this season by contacting Bradshaw at 308-632-1369.