Causal Agent:

Cuscuta species

Distribution:

Worldwide

Symptoms:

Dodder is a parasitic plant that forms a yellow or orange thread-like vine that winds around the above-ground parts of affected plants. These shoots produce pegs that penetrate into the plant to absorb nutrients. The vine spreads to adjacent plants as it continues to grow.

Conditions for Disease Development:

Dodder has a wide host range, including many weed and crop species. It produces tiny flowers in clusters which contain thousands of small seeds. A few seeds will germinate the first year, but the remaining seeds lie dormant for many years before germinating. In the field, the dodder emerges and twines around the onion seedlings.

Control:

Dodder may survive as debris or seeds on or in the ground, or it can be introduced into fields on equipment and in irrigation water. Therefore, early removal of dodder along with infected plants is the best method of control. Burning of residues and cleaning equipment thoroughly before moving it from dodder-infested fields to new areas help to control this parasitic plant. Herbicides and rotation to cereal crops may also provide control.

Note: This disease information was provided courtesy of Seminis Vegetable Seeds, Inc. 20028.