David Owens, Extension Entomologist, owensd@udel.edu
This week I had the chance to visit a hopyard in Newark. Both potato leafhoppers and mites were active. Thresholds in hops from other states are 2 leafhoppers per leaf and 2-5 mites per leaf. The mite threshold is the most problematic because of the potential for isolated hot spots to develop. Look at a couple of leaves per plant, from at least 5 plants per row or per variety. Focus on leaves about 3 feet from the ground. Portal’s label indicates it has activity against potato leafhopper in other crops but is not labeled for leafhopper in hops.