Thursday, June 19, 2008

Past Entanglements, Present Tense

It's ba-ack....

One knows the inflection of that phrase from hearing it in common use, in so many contexts, even if one doesn't even know what movie it's from. Such is our culture.

Last year, we only discovered one tiny plant of dodder, in a fallow area.

This year, suddenly there was a large, vigorous clump of the eery orange tendrils strangling one of our precious Pink Wink potato plants. EEEK!

At least it was a chance for apprentice J. to examine this pernicious parasitic weed. We carefully gathered up every fragment, pulling up the weeds it had attached to. We treat dodder and affected hosts as biohazard waste...which it is. We pulled it ever so carefully off of Pink Wink, and left the plant. We'll watch to see if it truly does regenerate from material remaining in the host plant vascular tissue, even though we've removed every external trace. (Sorry, I have not been able to figure out how to rotate photos since a computer revamp changed my photo viewing program.)

This parasitic plant became established on the farm while the tenants were here during my sojourn in Canada a couple years ago. Instead of doing some research and doing everything they could to eradicate it, when it started taking over patches of vegetables they just ignored it! They allowed it to seed, then they ran a rototiller through the contaminated bed and spread it all around! It was also allowed to seed prolifically on the pasture, and spread by animals dragging fragments of the tendrils onto host plants. It can regenerate from a small fragment that falls on a host plant.

Favorite hosts in the garden include tomatoes, potatoes, and onions...some of our favorites, too. In the pasture, it favors the best legume forages--red clover, for example. Though it's not supposed to attack grasses, it certainly seemed to be inserting itself into the vascular tissues of the foxtail grass in the potato bed.

It has no clorophyll. It has no roots. It draws all nutrients from the host plant. It wraps around the host, inserts itself into the host's tissues, and draws all water and sustenance fromt here. It isn't affected by herbicides because it doesn't grow like a plant; you can, however, use herbicides to kill it indirectly by killing the host. Not much gain there, if it's in a crop!

Where it attaches to a host, it can send out up to 25 tendrils, seeking other hosts to attach to. each attachment point can grow those 25 tendrils at a rate of several inches a day. Small severed fragments can attach and grow if they fall on a host.

The one plant-like thing it does is reproduce by seed. Thousands of seeds that can stay viable in the soil for 30 years.

This plant is one serious reason for not wanting the City to run construction euipment through our farm to build the pipeline. If seed is transported to our neighbor to the east, it could be a real disaster in his soybean field. Even one seed from my farm could result in a totally infected field, if he fails to notice that seed establishing a colony. He doesn't walk his soybeans nearly as frequently as I walk my pasture, and likely woulnd't notice a patch before it seeded profusely.
Where did this plant come from, to begin with? At first I suspected vegetable seeds. But then I discovered that dodder seed is banned--zero tolerance--in seeds offered for sale in all 50 states...the only such plant. Now I suspect it came steathily in a bale of hay, nearly-ripe seeds entwined around a bit of alfalfa.
Like the snapper, a bit of biodiversity I wouldn't mind doing without. Even if it is extremely fascinating, in its own creepy way.

No comments: