Downy Mildew on basil in greenhouse

[Julie Rubaud]

We are a certified organic greenhouse and were invaded by basil downy mildew this year for the first time. None of our basil was sale-able. We tried about 10 different varieties, a couple of different potting soils, and then started regular applications of Oxidate. Nothing worked, but we have no experience using Oxidate, and I don't think the twice a week spraying was enough. Any tips?

 

[Eric Rohloff]

Being on Basil and organic makes it a tougher problem. Best practice is a preventive program. Checkout these links for some pretty good info. I think there's a few copper based products label for organic and Downy control.:)
Basil Downy Mildew

Downy Mildew on Basil

[robert schuler]

Here in southern NJ a lot of work is being done to find a control for basil DM because we devote a lot of acres to this crop. DM is carried "IN" the seed and can not be removed by seed treatments. The only fungicides that seem to work are the phosphites.. K phite is such a product. The only organic treatment that worked and not very well at that was Actinovate. No other organic treatments controlled DM in field tests over the last two years. We all need to find a clean seed source... Bob.

[Julie Rubaud]

I have tried seeds from High Mowing Seeds and Johnny's. I haven't tried any other sources yet, but tried about 10 varieties for Have you had any luck with any vendors? I will try the Actinovate, thanks.

[Walter Gaipa]

Hi Julie,

Have you found any new treatments for organic downy mildew control on basil?

 

Walter

[Chris Sawyer]

keep the humidity under control and increase the air flow, oxidate @ 2 oz/gallon is what we use. I kept our basil going until the end of Nov in our house with no heat this year.

[Lloyd Traven]

Have you tried Cease, from Bioworks? Not aware of any phosphites that are organiic certified.

[Michael Pawelek]

Changing cultural practices is the only way to go until someone figures out a better organic product. When I start out my basil and it is in a small area of the greenhouse I place small box fans on the benches for better air movement. If the foliage isn't gently moving there isn't enough air movement. I realize keeping humidity low in the winter in greenhouses can be a problem but it is a must.

[Douglas W. Speed, Sr]

I reading the replies I see several folks have suggested the use of Cease and Actinovate. These products contain only one strain of bacillus subtills. I suggest you try the Revive version of Quantum Growth products which contains a consortium of subtills microorganisms plus other stains of benefical bacteria. visit www.doouglasspeed.com for details.

[Paul Cross]

Cease and Actinovate both carry OMRI labels and thus are pretty easy to get approval to use in an organic regulation. It would behoove the above poster to get his products OMRI listed if he wanted to make it easy for organic growers to consider them. It takes months for me to get approval on non-OMRI products for organic production. Note that his link has an extra "o" in it, if anyone cares to follow it.

I agree with Lloyd's suggestion of trying Cease. It stopped botrytis for us when we were having a problem with it. We fogged with it at night so there was almost no labor to apply.

Look at compost teas also.

Finally, we have had the best luck with basils from Vitalis / Enza Zaden. We're not doing fresh cut, but rather starts and potted. We have experience with the varieties Jolina and Emily.

[Walter Gaipa]

Chris,

Any issues with spraying Oxidate at 2 oz /gallon on basil? That is a pretty high rate and basil is a sensitive plant. Since Oxidate has no residual benefit how often do you spray?
 
Chris Sawyer said:

keep the humidity under control and increase the air flow, oxidate @ 2 oz/gallon is what we use. I kept our basil going until the end of Nov in our house with no heat this year.

[Chris Sawyer]

I use that concentration to cure, for maint. I use 1/oz gallon. I tried the 2 oz ratio on plants that were beyond saving, it cleaned them up. If the disease has progressed you have nothing to lose anyway. I spray after every rain, and every 7 to 10 days to keep diseases under control.

[Mark Langan]

Hi there everyone.

  Sorry I'm late to this discussion, I hope everyone is still following.  The holidays delayed in getting my profile setup are at fault.  First question, is this disease truly systemic, or semi-topical?  What I mean is, this, does this fungus grow it's mycelium into the stomata and the fruiting spores grow on the underside of the leaf(semi-topical and not an text book term), or does it transport throughout the plant to the growing points(systemic).  If this fungus does indeed grow "semi-topical" (grow with the first leaves and then sporulate up to the upper leaves?) then we have a chance to kill it in its' tracks (use any and all above suggestions).  If it is truly systemic and transports throughout the plant, then all we are doing is selling garbage, no matter what we spray to stop the spores, because the plant is thereafter truly infected.  For the customer to say " oh, I guess it was a bad year" will not allow us to stay in business.  If it is the former, then we have a opportunity to stop the spread.  I have been battling this for 3 years years , and am an Certified Organic grower.  Actinovate- do not waste money.  Oxidate / Preclude- no combination of sprays that I have tried have tried in the the field has worked with this (2% everyday X 3, followed by Actinovate + buttermilk- Cornell University), but for cleaning up an infected greenhouse has been great.  For greenhouse, remove all basils-then spray everything- under benches, floors, roof-everything!, spray peroxide 3-5 days in a row.  I have a Stihl backpack sprayer for the job.  For field, if you are in the south- you are probably (sorry) screwed.  In the north-pray for really hard winters.  Ann Chase was very little help on these issues.  What has been working for me,  has been peroxide for clean-up and then Suffoil-X  from BioWorks.  The Suffoil-X smothers the stomata and prevents sporulation. (I killed a great crop of Sage with the 4th spray, because I did not read the label) But does it prevent semi-topical sporulation on basil-if it does indeed grow this way?  It gave me a salable crop, but did the customers have a harvestable crop?

      Prevention, Please read.  I strongly believe and can confirm from Ann Chases article that the seed is infected (Organic seed from Johnnys will no longer be purchased).  But the question is once again, is it systemic or topical?  Robert Schuler said that DM is in the seed, Robert- help! got some research links to show this?  How is a fungus  "in the seed".  If this is true then my 3% peroxide soaks at 1 minute are worthless. P.S. No loss of seed germ., just a pain in the butt for sowing.  Lastly, ask for and know the seed source.  From India, Africa, Southern U.S. -in the words of a past famous N.Y. major " Foget about it".  Look for western U.S. or north as possible source.  Also ask these companies to certify that these fields were harvested from BDM free fields.  We as growers must collectively demand this.

   I hope I asked more questions than I gave solutions, to help us all keep this thread alive.

PEACE, Live and Long and Prosper.  Happy BDM free New Year!

Mark Langan, Mulberry Creek HerbFarm  419-433-6126