Extension Field Updates: Aphids in Alfalfa - UNL CropWatch, July 12, 2013
July 12, 2013
Jeff Bradshaw, Entomologist at the Panhandle Research and Extension Center at Scottsbluff: We are just creeping out of "alfalfa weevil season" and heading into "aphid season." Although a couple of our more damaging aphids, cowpea aphids and spotted alfalfa aphids, will not appear until later in the summer, another aphid is starting to show up in some alfalfa fields. The pea aphid is a long-legged, light to deep green soft-bodied insect. The threshold for pea aphids is 50 aphids/stem on 10-inch tall alfalfa and 100/stem on 20-inch tall alfalfa. The number present can be easily determined by shaking stems into a white bucket and counting the aphids.Products containing permethrin, chlorpyrifos, malathion, azadirachtin and others can be used to control these aphids. Check with current product lists for updated labels and restrictions.
Ron Seymour, Extension Educator in Adams County: Center pivots are running and a lot have been for several weeks. Dryland crops look okay but won't be able to hang in there a lot longer without some rain. Corn leaves have been rolling pretty significantly. Pastures are starting to dry up and there hasn't been a lot of regrowth after the last cutting. Wheat is being harvested in Webster County. There's not a lot of wheat in Adams County, but what there is has looked good.
Tyler Williams, Extension Educator in Phelps County: Wheat harvest is underway in the multi-county area and in some places is pretty poor due to extremely dry conditions. Reports of a soybean and a corn field full of false Japanese beetles, but no damage was apparent. Beans are growing well, but dryland corn is brown and leaves are curling.
Robert Wright, Extension Entomologist: Dectes stem borer beetles have been emerging at Clay Center since early July. Through a project funded by the Nebraska Soybean Board, we’re sampling fields in south central Nebraska for stem borer and monitoring emergence and egg laying. Beetles emerge and lay eggs over a long period of time, which is why we don’t recommend treatments, but rather monitoring before harvest. Affected fields should be harvested early to avoid problems with lodging.