Late blight strategies

[swampr]

I'd like to grow organic, but last year was a disaster on the tomato front due to a plague of late blight that hit during the 3rd week of July and spread through my entire tomato crop within a week.

I am aware that many have success with copper and daconil.

I'm looking for alternatives that are less toxic outright, or leave less residual toxic metals. Organic solutions would be optimum.

I was thinking zinc is less toxic than copper for example... Would zineb be effective?

Can anybody give me advice or point me in the right direction?

[skip]

G'Day Swampr!

I know nothing about the control of late blight but I have read that there are tomato varieties that have some resistance to it, such as Legend.

Another option for controlling late blight is to grow plants in a greenhouse environment.

Skip

[klorentz]

How about pray. Seriously. Here in Michigan we where under a warning last year. Some areas where about 25 to 30 miles away that did have late blight.Guess I was lucky we did not get it.


Kevin

[jcm05]

I plan on growing a couple varieties with known LB resistance. I also plan on growing Daniels again as last year it appeared to exhibit resistance. It was the last plant standing in my garden when every other one was devastated. I don't plan on using chlorothalonil again.

[amideutch]

Agri-Fos and Azoxystrobin. Ami

[swampr]

that's a helpful start ami, heres some more info:

en.wikipedia.org/wiki/Azoxystrobin

www.agbio-inc.com/agri-fos.html

[peppereater]

quote re:john
I don't plan on using chlorothalonil again.
As I've been able to gather, that is a good idea. I am not the scientist mule is, and don't go researching these issues via technical papers. Not much anyway. I just have not had that many problems with much other than early blight, don't ask me why. I do believe there was higher than usual rainfall nationwide last year, if that is a factor.
Copper Oliate and Bordeaux are not forbidden in organic production, although runoff is dangerous to marine life, fish and micro-organisms. Sulphur alone is a somewhat effective fungicide but possibly not adequate. As ami might attest, some of the bioactive micro-organisms may be quite effective, either as soil additives, or applied as foliar spray, I can't say I've researched that other than to say these myccorhizal and other organisms, and the beneficial relationships with some crops, show promise for disease tolerance in many crops.

[stratcat]

Feb 6, 2010 21:39:34 GMT -5 jcm05 said:

I plan on growing a couple varieties with known LB resistance. I also plan on growing Daniels again as last year it appeared to exhibit resistance.

Hi, John! Good to see you.

Which varieties are resistant to LB? My gardens lucked out last year. Had a couple friends call who lost all their tomatoes.

[jcm05]

Feb 8, 2010 23:40:23 GMT -5 stratcat said:

Hi, John! Good to see you.

Which varieties are resistant to LB? My gardens lucked out last year. Had a couple friends call who lost all their tomatoes.

Great to see you made it over John. I'm growing Mountain Magic F1 and also West Virginia '63. Hopefully though, I will not be "testing" their resistances!

www.bejo.cn/gba/upload/pdf/347/Bejo%20Tomatoes%20Eastern%20U.S.%202009.pdf

[stratcat]

Thanks for the info. Good luck.

[peppereater]

One other product touted as a pesticide/miticide/fungicide is NEEM oil. Can't say offhand what all fungi it's labeled for. I also can't vouch for its effectiveness in the garden on other that spidermites. Approved for organic use.

[nolika]

Hi, everyone, I'm new here, from Slovenia!

Each year we get blight very early (end of August) and it wipes out all the plants in matter of days. There are three solutions to this problem I use...
One being planting varieties that ripen before that date (very early varieties), the other being using an organic soda spray - really helps - that I found on the internet and modified a bit (I will post about this later, I have to dig up the 'recipe' ) and the last being pruning my plants severely to allow plenty of airflow.

Many gardeners here use plastic roofs (not greenhouses, just simple construction with some plastic cover) for their tomato plants, so the plants don't get too wet on rainy days and dry quicker ensuring the fungus not to spread to fast. But that really looks ugly in a nice garden, if you know what I mean.

Oh, one plant that did well for me last year, although it was planted with all others that got sick, was 'Matt's Wild Cherry'. That one had lots of tasty little toms up to frost (and we can't EVER have fruits up to frost here , no matter how much we try, so that was an accomplishment ). Another one I heard was good is 'Tomatito de Jalapa' but I'm yet to try that one...

It's nice to be here

[jcm05]

Welcome nolika! I had late blight pretty bad last year that first appeared in the beginning of July. I used chlorothalonil to control it until I could harvest the crossed fruit. Once I did that, I stopped spraying and within weeks most plants had given up the ghost. Except for one that exhibited what appeared to be substantial resistance to the pathogen. The variety was 'Daniels'. Now mind you, this was by no means a very scientific observation and I really have no way of testing it, but I do plan on growing the variety again for years to come as it is a very good tomato. I just hope that I don't get to test this hypothesis again.

[amideutch]

Yes, putting a roof over the plants definitely helps keep disease at bay along with periodic fungicide spraying. Both my open greenhouse on the left and would frame with roof on the right. Ami

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[nolika]

Wow, Ami, that wood frame looks great. Did you make it yourself? Here, everyone just 'throws' something up together and put plastic over it and that really looks nasty. But this frame of yours is something I would love to have in my garden, without being ashamed of it

Oh, I still have to find the soda spray recipe. Tomorrow, gotta go to bed now