The threshold under hot, droughty conditions is 2 leafhoppers per trifoliate, once the edible beans begin to flower. When edible beans are under stress, leafhoppers will likely impact yields greater. A driving rain is effective in reducing leafhopper numbers. In alfalfa, leafhoppers will cause yellowing of leaves, stunting of growth, reduced vigour, and loss in protein. Populations will build in alfalfa under hot, dry weather.
Spider mites are evident in some soybean fields at low levels.
Populations will build, under hot and dry conditions. Spider mites feed on the plant juices, resulting in leaves appearing puckered and sandblasted. A natural pathogen, which controls the spider mites, develops under sustained cool and humid conditions. There have been recent reports of pockets of yellowing in soybeans. These fields should be closely examined to determine if soybean cyst is the culprit.