??Biological fungicides

On Friday 23 Sept, I’m going to a talk on Companion Biological Fungicide by a rep from Growth Products, which has received FDA approval for its use as a soil drench for greenhouse use.

Answers to what specific questions would be of use for RHA members?

Link: www.growthproducts.com/news/pr_companion_biological_fungicide.cfm

Title: Biological control of damping-off of tomato seedlings and cucumber Phomopsis root rot by Bacillus subtilis RB14-C.

Authors: Kita, Nobuhiro; Ohya, Takeshi; Uekusa, Hidetoshi; Nomura, Ken; Manago, Masahumi; Shoda, Makoto.

Authors affiliation: Division of Biotechnology and Bio-Resources, Kanagawa Institute of Agricultural Science, Kanagawa, Japan.

Published in: JARQ (2005), 39(2), pages 109-114.

Abstract: “Bacillus subtilis RB14-C, which is a streptomycin resistant mutant of B. subtilis RB14 isolated from compost, produces an antifungal peptide, iturin A, and was evaluated for its suppressive ability against damping-off of tomato seedlings and Phomopsis root rot of cucumber. In damping-off disease of tomato seedlings caused by Rhizoctonia solani, RB14-C cell suspension treatment did not suppress the disease occurrence whereas germinated seed treatment of the RB14-C cells reduced the occurrence of the damping-off. In both treatments, iturin A could not be detected from the treated soil. In the Phomopsis root rot of cucumber, root immersion treatment of cucumber seedlings with RB14-C cell suspension at the time of transplanting effectively suppressed the root rot, resulting in growth recovery 50 days after the treatment even though the initial growth was retarded due to the Phomopsis infection. These results suggest that germinated seed treatment of RB14-C cells and root immersion treatment with RB14-C cell suspension can be applied as promising biol. control practices of the damping-off of tomato seedlings and the cucumber Phomopsis root rot, resp.”

Title: Co-utilization of Bacillus subtilis and Flutolanil in controlling damping-off of tomato caused by Rhizoctonia solani.

Authors: Kondoh, Maki; Hirai, Mitsuyo; Shoda, Makoto.

Authors affiliation: Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama, Japan.

Published in: Biotechnology Letters (2000), 22(21), pages 1693-1697.

Abstract: “Damping-off of tomato caused by Rhizoctonia solani was controlled in a pot test using the biol. agent, Bacillus subtilis RB14-C, and the chem. pesticide, Flutolanil. The co-utilization of B. subtilis RB14-C, and Flutolanil decreased the amt. of Flutolanil used from 375 mg/pot when Flutolanil was used alone to 94 mg/pot, while exerting the same effect of reducing disease occurrence.”

I realize that this is a little off the subject of the post, but it fits the title of “biological fungicides”, and I’d forgotten about it until I saw this post, so…

I have a found/collected OGR (Old Garden Rose) that I’ve used several times as a seed parent, that has an exasperating tendency to get heavy growths of mildew on it’s hips. This causes them to rot and drop off. Two years ago, I pollinated as many of the blooms on that rose as I could, planning for many hips to be lost. Once the petals dropped some started getting the mildew, as I’d expected. So, on a whim (and thinking of the fungicidal properties of some plants) I squished wild onions (weedy Allium sp. from the lawn) and rubbed the juice over the patches of mildew on several hips. This seemed to stop the mildew in its tracks. I reapplied several times over the growing season and got almost all of those treated fruits to maturity. Untreated ones rotted through and dropped off as expected.

I’ve also used juice from crushed leaves of another weed, garlic mustard (Alliaria sp.) and it seems to work too.

(To bring the thread back to the original intended subject)

I wonder if damping off fungus might be susceptible to any of these types of biological fungicides.

Soap and water will work, as will alternate sprayings of a vinegarsolution with a baking soda solution