Last week Jay was out in one of our non-crop areas and found dodder! Dodder is one of the few truly parasitic plants found in North America. It looks like golden hair growing on top of the crop. Given enough time it can completely engulf an entire area. Here is a photo from Wikipedia of dodder covering an entire tree.
Dodder initially grows from seeds. Once it establishes itself on the host plant the dodder loses it’s connection from the ground and grows entirely on the host plant. The dodder inserts a small appendage called a haustoria directly into the host plant to extract water and nutrition so it has no need to be connected to the ground. Most dodder is not even green meaning that it doesn’t have much chlorophyll. It doesn’t need the chlorophyll because it is not creating energy from water and sunlight, it is sucking it out of the host!
One of the biggest problems with dodder is that is extremely hard to get rid of, especially for organic growers. You can’t just pull out the dodder and burn it or compost it because even the tiniest piece of dodder that is attached to a living plant will grow again. It has to be completely eradicated. Non-organic growers can try to control dodder by using pre-emergence herbicides to prevent the dodder seeds from coming up. If the dodder is already growing on a host crop many growers will use a burn-down herbicide such as glyphosate to kill the host. Without the host plant to extract nutrition from, the dodder will die. Another strategy for controlling dodder is to alternate crops to a non-host. Dodder grows much better on dicot plants and doesn’t really grow very well on grasses (monocots). So, in theory a grower could put a field into grass, wheat, or corn production in an effort to control dodder.
The dodder we found was very small and just getting started. We were lucky! It was also growing in a non-crop area so we didn’t have to worry about destroying a valuable crop. We decided the best thing to do was to simply burn the infested area. It destroyed not only the host plant but also the existing dodder.
We will be keeping a close look out for this invasive parasitic plant. I will not be surprised to see it pop up again. I was chatting with a farmer friend at the market a few weeks ago and he was finding it in his cropping area. There was no option for him other than to destroy the crop. If you find it on your property or farm, get rid of it. Do it quickly! Don’t let this terrible parasite get started.