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