Relationship Between the Dodder & the Marigold

Dodder Function

• Dodder has no roots or leaves. There are several species, and they have specific host plants. Like all plants, it produces seeds with flowers. The flowers can remain dormant for years until optimal conditions cause germination. When it germinates, it will send a tendril through the soil to attach to its host. If there is no appropriate host, the plant will die.

Dodder Control

• The best control for dodder is removing all infected host plants. It's best to remove the plants before the dodder produces flowers and seeds. Killing the host plant will also kill the parasite. Since dodder has specific hosts, plant rotation is a useful tool to prevent its return. Some gardeners treat their soil with pesticides to reduce dodder, but be sure to follow precautions carefully and avoid treating areas that will be used for edibles.

Parasitism

• A parasite is completely dependent on a host to live, grow and reproduce. While parasites may not kill their hosts, they can cause disharmony in an ecosystem by making the host organism weaker. If the host organism fails to thrive, it can affect all organisms in its environment -- including the parasites that depend on it.

Types of Parasitic Plants

• The main types of parasitic plants are holoparasites, root parasites, nonphotosynthetic vines and hemiparasites. Holoparasites include mistletoes. They obtain nutrients from their host, but also photosynthesize. Root parasites have fleshy nonphotosynthetic stems, but some can have photosynthetic leaves to augment nutrients. Nonphotosynthetic vines belong to the morning glory family and include dodder. Hemiparasites have photosynthetic leaves, but most of the nutrients come from the host's root system.