Looking for biological remedy against botrytis

[svalli]

Last year I lost many tomatoes in my greenhouse to botrytis. I have been looking for non chemical remedy for this year.
So far I have found two products:
Prestop, which is used by commercial growers and is based on beneficial soil fungus.
Biocin, which is quite new herbal extract.

I'm sure Prestop will work, but it is difficult for me to buy, since it is normally sold only to commercial greenhouses.
The Biocin sounds like some of the other magical potions with more marketing than actual results. Since it is relatively new product no one may have tried it yet. If I find it in any of the garden centers here, I may have to try it with few plants.

Sari

[saltmarsh]

Hi Svalli

I've been trying Equisetum (Horsetail or Scouring Rush) and it seems to work. I remove any damaged leaves and bag them for disposal then spray all of the plants until wet all over.

http://en.wikipedia.org/wiki/Equisetum

To make the tea I prefer to use fresh horsetail fronds 2 1/2 to 3 feet in length as these are much easier to cut than dry horsetail.

I cut six of the mature green fronds into 1/4" pieces using a paper cutter. Bring 1 gallon of water to a boil. Add the chopped fronds, cover the pot and reduce heat to a slow boil and slow boil for 10 minutes. Remove from heat and allow to stand for 24 hours.

Strain into a 1 gallon jar and top off with water to make 1 gallon of tea.

The variety I'm using is Equisetum arvense, the Field Horsetail or Common Horsetail http://en.wikipedia.org/wiki/Equisetum_arvense

If you are treating an active infection mix 1 part horsetail tea with 4 parts water (1 gallon of tea makes 5 gallons of spray). If you're using as a preventative spray, mix 1 part tea with 9 parts water (1 gallon of tea makes 10 gallons of spray).

Spray once a week.

If you are using dry horsetail, use 2 oz of horsetail per gallon of water to make the tea as above.

I normally make 3 gallons of tea at a time which makes 30 gallons of spray.

I hope this helps, Claud

[svalli]

Thanks Claud, The arvense also grows in Finland, so I have to go to look for it in the fields. We have some Horseail grow in the middle of the road through the woods to our summer gottage, so it may be Equisetum sylvaticum. I wonder if it would be as effective.

Sari

[saltmarsh]

Svalli, I only use the species arvense.

From my link above:

"The plant contains several substances which can be used medicinally. It is rich in the minerals silicon (10%), potassium, and calcium.[citation needed] The buds are eaten as a vegetable in Japan and Korea in spring time. All other Equisetum species are toxic. In polluted conditions[citation needed], it may synthesize nicotine.[3] Externally it was traditionally used for chilblains and wounds.[4] It was also once used to polish pewter and wood (gaining the name pewterwort) and to strengthen fingernails. It is also an abrasive. It was used by Hurdy-Gurdy players to dress the wheels of their instruments by removing resin build up.[5]
It is used in biodynamic farming to make the "silica" soil preparation.[clarification needed] (BD 508) Equisetum in particular is used because silicon reduces the effects of excessive water around plants that would lead to fungus. It is the high percentage of silica in the plant that works on lowering the impact of moisture.[6]"

[bower]

Just having my first serious brush with botrytis in 2012. This time it's hot and humid weather, instead of cold and wet as last year. Last year it was really devastating. And today I found black patches on stems of my Black Sea Man that is loaded with green tomatoes. When stems rot it's catastrophic. I need to keep these stems alive if possible until the fruit have ripened.

I read your posts earlier this year and looked for horsetail in a place I had seen it, but found none.

I found a pdf (Wilson) in my search for antifungals, where they tested 256 plant extracts and some essential oils for antifungal activity against Botrytis cinerea. Clove oil is the only one I have on hand, which they reported to inhibit Botrytis completely for 40 hours at concentration 1.56%.

So I pruned away any affected leaves and twigs, and used a q-tip to swab the cuts with clove oil, also the black stem areas.
I went out in the yard and found some lichen we call Old Man's Beard on a tree, so I decided to use it as a wrap around the treated stems, maybe help to keep them dry and isolated from other parts. I will take a look at those after 40 hours, decide whether to reapply oil....

I tried Cinnamon oil and some powdered cinnamon last year - the powder was okay to stop infection of a pruning cut, but only if applied immediately. It did not help existing infection of the plants.

[saltmarsh]

Hi bower, sorry for your troubles. To find horsetails in your area, I'd first ask your electric meter reader if you have those, then the gas meter reader, then the local postman, followed by vets who visit the farms in your area. If you haven't found an ample supply by then, I'll offer further suggestions. I'm still using it and quite happy with the results. Claud

[bower]

Thanks Claud. I'm going to check that place again next time I go to the beach.

For others who may be struggling to develop a local treatment strategy, I also found this PLoS full text about botrytis antifungal activity in resveratrol and other stilbenes from grapes, and Cotoras 2004 abstract reporting on the activity of hydroxylated diterpenes (kauranoic acid derivatives) from another plant in Spain. They are in vitro studies.

For my greenhouse situation the ideal treatment for an existing infection should not add to the humidity in the space - the humid condition favours botrytis apparently whether it is hot or cold. I'd like to try the horsetail topically - make a strong extract perhaps - to apply directly to infected stems that I can't just remove, and I will have to keep up rigorous sanitation and removal of any other infected parts.

When reading about this last year, I learned that pollen and senscent tomato flowers contain substances that stimulate the growth of botrytis. This seems to vary with different varieties - Peacevine set and dropped a great number of blossoms in the cold wet weather last year, and the dropped blossoms were covered in mold and infected foliage and stems before I realized what was happening. Black Cherry flowers seemed to be very resistant to the fungus or simply have a low level of whatever it is that stimulates botrytis to grow. So I'm watching the flower characteristics and drop patterns of the varieties I'm growing this year, to assess the botrytis risk characteristics. I'd like to hear what others have learned about varieties that are especially susceptible or resistant.

We had a cool night last night and - bad news, another black patch has shown up on the infected stem. The infection also seemed related to the support system used - chafing by the rope, so I removed it and then I could see, that the infection has spread rapidly up and down the stems. So much for clove oil to inhibit this botrytis - or whatever it is - the surface looks brownish more than grey. It is certainly a fast spreading rot, and the treatment did not help, so I think I will have to bite the bullet and hope to ripen the green fruit off the vine. I must remove it, can't risk this spreading to the other plants.

[amideutch]

Here is some info I came up with on the web. I'll do some more looking for products here in Germany as they are getting into BioControl big time. Ami

http://www.ncbi.nlm.nih.gov/pubmed/17390837

http://www.landwirtschaft-mlr.baden-...ruckansicht=ja

[amideutch]

Just came across this product. If you need any help purchasing it let me know. Ami

https://biokeller.de/Garten/Pflege-S...ichoderma.html

[bower]

Ami, thanks for bringing up Trichoderma. I did find a T. harzianum product in Canada called RootShield, and they say it can be used as a foliar spray to suppress botrytis. Too late for this year, perhaps I can get it for next.

I see also that Trichoderma could be found in any organic soil or compost, and favoured by the presence of bacterial communities as in a living soil. But these species will not grow above 35C, so the hot temps lately in the greenhouse would make it difficult to use effectively on aerial parts. I would expect to find Trichoderma in the soil in my containers though, as it's a mix of my own and commercial compost, a little garden soil, and fresh chopped kelp - the worms like it. I don't know what the soil temperature might be at present, but perhaps I should try a mulch to keep it cooler.
I must admit, it looks like it would be impossible to isolate the desired Trichoderma spp. from a local soil source without a full lab workup.

I've added some pictures of the stem rot to my Black Sea Man/Chernomor album and I'll try to link them here:
The brown streaks shown on this stem appeared overnight above the infected area.
The second stem also developed a black line moving the infection upward.
The plant had a total of 40 fruit on it: 29 came down with the infected stem and 11 are left on what remains of the plant.
It's sad to see such a good producer is also so susceptible to the blight.