a) are small (1/8 of an inch), wedge-shaped and gray to yellow with three pairs of spots between its eyes
b) can vector Aster Yellows which can cause yield loss in wheat
c) become infectious after feeding on an infected plant for 30 minutes AND incubating the disease (in its body) for 9-21 days
d) remain infectious for an extended period of time
There is little research and no economic threshold, since they are rarely a problem….
In the 1930’s, there was 1 paper that stated that an “insecticide treatment should be considered when disease symptoms are noticeable and leafhopper numbers are high (clouds when you walk in field).”
This is an individual, field by field decision, but many of our herbicide sprays will be applied with a pyrethroid insecticide.