HPIPM:Onion Aster Yellows

Taxonomy

Domain	Bacteria
Phylum	Tenericutes
Class	Mollicutes
Order	Acholeplasmatales
Family	Acholeplasmataceae
Genus	Candidatus Phytoplasma

Scientific Name

Candidatus Phytoplasma asteris-related strain

Common Name

aster yellows phytoplasma

Author: Howard F. Schwartz and Michael E. Bartolo

This disease is caused by the aster yellow phytoplasma which affects many weeds and crops including onions, carrots, lettuce and celery. The pathogen is transmitted by the aster leafhopper (Macrosteles quadrilineatus Forbes). Symptoms initially appear as a yellowing at the base of young leaves, which then spread toward the top. Leaves flatten, become marked with green and yellow streaks, but do not twist. Flower stems are abnormally elongated, and have malformed, sterile floral clusters.

Disease management recommendations include crop rotation out of onions for three years; elimination of weed hosts in and around onion fields; insect control; and isolation from other susceptible crops or volunteer onions.

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.