We looked at some of the bacterial biological controls sold commercially and found that they unfortunately didn’t provide useful control against black spot…
http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2008/OT005.pdf
Dave neither link is accessable on my computer. Could you tell us which active ingredients the tested products contained (I am particularly interested in knowing whether any were T. harzianum based.)
Thanks Henry,
I was at the U of Minnesota Library earlier in the day when I wrote the previous post and put the links in. It must have worked from there because they have subscriptions to the journal. I’m at a coffee shop now and they aren’t working.
This is what we tried and reported: Rhapsody AS (Bacillus subtilis), Sonata ASO (Bacillus pumilis), Concern Garden Defense (Neem oil), Fung-onil Concentrate (Chlorothalonil), and an untreated control.
The Chlorothalonil control worked great as expected but the more natural products were not significantly different from the untreated control or so minorly different at just a portion of the rating dates that it didn’t provide practical control.
David
Jim and Pierre,
I have always felt that there was a physical/mechanical side of disease resistance as well. I halve also noted that roses that exhibit this property, do so best when the foliage is hardened off. Also, I think it factors in why good overall plant health is important in overall disease resistance in a relative way.
Today I had a phone call with a man that pioneered in Trichoderma harzianum products beginning more than twenty years ago.
He told that this funghus use is very good to fight pithium and other harmfull substrat or soil funghi but that results for foliage deseases are deceiving. For this purpose he has an extracted Trichoderma molecule that triggers foliage defences.
Within a week or two I’ll try his Trichoderma “Solsain” on my sowing trays.