Giant Knotweed Extract: An Organic Fungicide

A giant knotweed (Reynoutria sachalinensis) cluster grows outside my window, put there to offer some summer shade and be cut down in fall to return the southern sun. Seemed like a good idea at the time, as knotweed gets over 12 feet high and was much easier to get going and more drought tolerant than bamboo. But as I found out, knotweed is also highly invasive. And, it grows a half foot per night. Yipes. Way too renewable for my taste. So, I'd been thinking for some time about pouring a couple of gallons of horticultural vinegar on the root clusters, untangling myself from the knot I'd woven. Then this news: a simple exract of plant tissue using alcohol results in a botanical fungicide that EPA looks ready to permit for commercial use. More details below the fold.

The proposed USEPA rulemaking "establishes an exemption from the requirement of a tolerance for residues of the biochemical pesticide Reynoutria sachalinensis extract on all food commodities. The Interregional Research Project Number 4 (IR-4), on behalf of KHH Bioscience Inc, submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA)".

Perhaps you've heard of "induced resistance" as a pesticidal strategy. Knotweed extract "induces phytoalexins which infer resistance to powdery mildew and other diseases such as Botrytis". In other words, the extract helps the crop or ornamental plant fight the mold rather than attacking the mold directly. If the extract were made with organic alcohol, the fungicide should be considered organic. An invasive organic fungicide: 'now that's what I'm talking about'.

Powdery mildew gets my pumpkins, squash, cucumbers and grapes, cutting off yield right at the peak. Usually comes after a hurricane remnant throws a week of rain. Payback time. One question remains, do I make my own fungicidal exract with a gut-rot grade of rum or wait for KHH to offer it's new product (might be called MILSANA) at the retail level? Think I'll leave that knotweed for a bit more.


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