This weeks' topic is an unusual weed called dodder vine.
Dodder vine is a parasitic annual weed. It is leafless with thread-like yellow, tan, or creme colored stems. It looks like spaghetti is on the plant.
The vine sprouts from seed and twists around the stems of the host plant it is attacking. The dodder stems then send out short suckers that look like suction cups. They attach themselves to the stems of the host plant and penetrate the stems to take nourishment through the suckers. Dodder stems will branch out repeatedly to go after other hosts. As the dodder vine matures and becomes attached to to a host plant, its roots will die and it lives exclusively off the host plant.
White or creme colored flowers produce the seed from April to October. It can germinate the same year, or lie dormant until the following year.
Control is hard to achieve because once it's attached to a plant it can not be removed. Cutting out the infected area does not guarantee the dodder will not reappear. It is best to destroy badly infected plants.
It is better to prevent the seeds from germinating next spring by applying a preemergent herbicide like trifluralin, the product in Preen. Apply in early spring (around the time of the last frost) and again six weeks later.
On the organic front, there is nothing known to prevent dodder. However, disease organisms that will infect dodder vine and kill it are being looked into.