Forages & Grains
Volume 62 Number 14 Date 08/03/2017
POTATO LEAFHOPPER - Counts remain below the two-leafhopper-per-plant economic threshold for alfalfa 12 inches and taller in southern and west-central fields, with most sites having averages less than 0.6 leafhoppers per sweep. Above-threshold counts have not been found in the past two weeks. Heavy rains in July and harvesting of the second and third alfalfa crops appear to have reduced populations from the high levels observed 3-4 weeks ago. Nymphs are still very common in sweep nets, indicating that populations could still increase in August.
GRASSHOPPER - Late-season grasshopper activity is escalating in alfalfa and other crops. Defoliation has become pronounced along field margins since mid-July across the southern two-thirds of the state. Grasshopper damage to forage crops can be serious at this time of year, especially in new alfalfa seedings and when dry weather slows plant regrowth after harvest. Chemical intervention is not necessary unless populations reach 20 grasshoppers per square yard at the margins or eight per square yard within an alfalfa field.
-- Krista Hamilton, DATCP Entomologist