I am starting to get reports of grasshoppers in some early planted soybean fields. We are starting to see this now that rye is being harvested. Some of these soybean fields can be susceptible to feeding from grasshoppers. The feeding can result in stand loss. When stand losses occurr from emergence to the second trifoliate a treatment might be necessary. It is difficult to find exact treatment thresholds for grasshoppers. Guidelines often used for treatment are 30% or more defoliation with one or more grasshoppers per sweep with a net. It is generally not too difficult to tell if grasshoppers are abundant, so don't worry if you do not have a net. This guideline is used from emergence to the pre-bloom stage. Many times grasshoppers are concentrated along field edges or ditches, so it may be possible to only treat the areas where grasshoppers are found.
Tuesday, June 7, 2011
For more than a decade, a general decline in ECB adult moth populations and larval infestation rates have been seen in most crops. Generally entomologists in the eastern US are attributing this long decline in ECB to increased production of Bt field corn which would be a dead end host for the pest. An adult moth population bucking this trend is widely observed this spring 2011. The reasons are unclear but it is a fact. Growers are advised to scout all whorl and pre-tassel fields.