The white apple leafhopper is the most common leafhopper found on apples in the Pacific Northwest. Until it became a pest of significance in Washington in the mid-1970s, specific control measures were rarely needed. Resistance to organophosphates is the most likely cause of increased populations. Since about 2000, it has again become an uncommon pest in most orchards, likely because of the shift away from pesticides toxic to its primary parasite.
For more information on life stages, damage, monitoring, and management of the white apple leafhopper, go to Washington State University’s online orchard pest management guide at http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?pn=360.