leafhopper

"But I just don't know how many prune trees are enough." The long-term goal is to eliminate spraying for the grape leaf-hopper.

Al Zadjali, who has a PhD from the Tokyo University of Agriculture and Technology, points to a part of the tree with small, bushy leaves that look similar to flowers, and explains that this is another symptom of WBDL, which is caused by a microorganism bacteria called 'phytoplasmas.' The 'phytoplasmas' are carried from plant to plant by insects, usually leaf-hoppers. They cause leaf-like structures to grow in place of flowers, yellowing leaves, and dead branches that look like witches' brooms.

sugar beet producers also battle beet curly top virus, which is transmitted by beet leaf-hoppers. Back in the lab, Eujayl set out to develop a set of genetic markers that plant breeders could use in developing curly top-resistant sugar beet varieties.

They over-winter in parasitized eggs of other leaf-hoppers found in prune and plum trees and blackberry vines planted nearby, hatch and then parasitize grape leafhopper eggs in adjacent vineyards.