Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
Forage Grass
Baythroid XL recently received an expanded label for forage grass. The following is the link to the new label (http://www.cdms.net/LDat/ld7JO034.pdf).
Soybeans
We continue to see high levels of bean leaf beetles, especially on the western half of the state from Greenwood through Middletown. Remember, at this time you will need to consider a treatment for defoliation as well as consider their ability to feed on the pods. At the pod fill stage, the defoliation threshold drops to 10-15% defoliation. This insect can also feed on pods. Bean leaf beetles can clip pods or plant diseases may enter the pod through their feeding sites. This can result in seeds that appear shrunken, discolored, and moldy resulting in a reduction in seed quality. Although we have not established thresholds for pod feeding in our area, the following link provides information that is used in the Midwest (http://www.ipm.iastate.edu/ipm/icm/2000/8-21-2000/lblroof.html). They have also included some new information in a recent newsletter that may better address the pod feeding aspect. It should be noted that we may be ahead of them in emergence of second generation since we have been seeing newly emerged soft gray beetles (http://www.extension.iastate.edu/CropNews/2008/Issues/20080728.htm). Also, we do not have any data on bean leaf beetle control in our area. When possible, a material with residual control should be used. However, the presence of other pests, especially mites, will impact your selection of a control material.
You should also scout for stinkbugs and pods worms as we enter the pod set and pod fill stages. In VA, Ames Herbert reported last week that they are expecting the major corn earworm moth flight to begin a little earlier than normal based on what they are seeing in their corn survey, which is still in progress. We continue to have high corn earworm trap catches in some locations; however, only time will tell if this will translate into a major podworm outbreak in soybeans. Although we are finding low levels of corn earworm in full season soybeans, this is not unusual for this time of year and only scouting on a routine basis will tell you if you have an economic problem. As trap catches increase, open canopy blooming fields will be attractive to egg laying moths. A treatment should be considered if you find 3 podworms per 25 sweeps in narrow fields and 5 podworms per 25 sweeps in wide row fields (20 inches or greater).