After a dodder attaches itself to a plant, it wraps itself around it.
If the host contains food beneficial to dodder, the dodder produces haustoria that insert themselves into the vascular system of the host.
The original root of the dodder in the soil then dies.
The dodder can grow and attach itself to multiple plants.
In tropical areas, it can grow more or less continuously and may reach high into the canopy of shrubs and trees; in cold temperate regions, it is an annual plant and is restricted to relatively low vegetation that can be reached by new seedlings each spring.

Dodder is parasitic on a very wide variety of plants, including a number of agricultural and horticultural crop species, such as alfalfa, lespedeza, flax, clover, potatoes, chrysanthemum, dahlia, helenium, trumpet vine, ivy and petunias.
It is an ectoparasite and is categorized as holoparasitic plant, or a plant that is non-photosynthetic and is completely dependent on a host.

Dodder ranges in severity based on its species and the species of the host, the time of attack, and whether any viruses are also present in the host plant.
By debilitating the host plant, dodder decreases the ability of plants to resist viral diseases, and dodder can also spread plant diseases from one host to another if it is attached to more than one plant.
This is of economic concern in agricultural systems, where an annual drop of 10% yield can be devastating.
There has been an emphasis on dodder vine control in order to manage plant diseases in the field.
After a dodder attaches itself to a plant, it wraps itself around it. If the host contains food beneficial to dodder, the dodder produces haustoria that insert themselves into the vascular system of the host. The original root of the dodder in the soil then dies. The dodder can grow and attach itself to multiple plants. In tropical areas, it can grow more or less continuously and may reach high into the canopy of shrubs and trees; in cold temperate regions, it is an annual plant and is restricted to relatively low vegetation that can be reached by new seedlings each spring.
Dodder is parasitic on a very wide variety of plants, including a number of agricultural and horticultural crop species, such as alfalfa, lespedeza, flax, clover, potatoes, chrysanthemum, dahlia, helenium, trumpet vine, ivy and petunias. It is an ectoparasite and is categorized as holoparasitic plant, or a plant that is non-photosynthetic and is completely dependent on a host. 
Dodder ranges in severity based on its species and the species of the host, the time of attack, and whether any viruses are also present in the host plant. By debilitating the host plant, dodder decreases the ability of plants to resist viral diseases, and dodder can also spread plant diseases from one host to another if it is attached to more than one plant. This is of economic concern in agricultural systems, where an annual drop of 10% yield can be devastating. There has been an emphasis on dodder vine control in order to manage plant diseases in the field.
Cuscuta