I sincerely doubt late blight is overwintering in zone 4. I would personally go ahead and use your soaker hose in your field that was used 2 years ago for potatoes.

From what I know:

--- LB bacterium is "air borne".
--- It cannot live/survive/over winter in soil.

Therefore, plant rotation cannot help in any way to prevent it, b/c it is not soil borne.

Late Blight is a bacteria, Phytopthera infestans, but it's the spores that it makes that are infectious which are transmitted by wind and embedded in raindrops.It is not a soilborne disease as you mentioned above

Were your potatoes infected with LB or EB? If so, since LB can only survive in living tissue and in your zone the plants would bekilled as mentioned above.

But if you had enough potatoesto form cull piles, then yes,LB could exist in those over the winter and serve as a source of infection.

Where I live in NYS the western part is a potato growing area and in those years where there are alerts, LB is not present every year, infection of plants where I live in the East originates from those cull piles.

Lastly, are you sure it's Late Blight and I ask since disease with Grey Mold is often misdiagnosed as LB/

Carolyn

Here is a picture of the "mess". I assumed it was late blight because the potatoes went down at the same time. If it's not in the soil then I don't know where it came from unless it was in the potatoes I planted and they perhaps died back first and spread it to tomatoes

It probably came from the air. Every year this thing spreads throughout the NE of the USA via the air.

Prophylactic spraying with fungicides can help since your garden is LB prone. I know many organic growers here use copper. Moving the garden out into the sunnier spot will surely help too.

Considering that you are in zone 4b, at this pint , your season probably practically is over. With cold and possibilities of rain, you could not do anything to help for all practical purposes.

What I would do (next season) s to keep the lower parts of my plants pruned, to allow a good air flow. Then I would spray them systematically shortly after plant out , at an interval of about 2 weeks.
Good luck the next season !

I fungicide weekly, from day one, with this organic Copper Fungicide (Bonide).

I am sure that the synthetic Daconil (Chlorothalonil) is much stronger than Copper, but I prefer to call it an end to my tomatoes, than to use the potentially dangerous Daconil.

See EPA > âÂÂOn September 4, 1987, the Agency classified chlorothalonil [Daconil] as a Group B2 or probable human carcinogen.âÂÂ

Some of my tomatoes. No disease at all. Thank you Copper.

This post was edited by Daniel_NY on Mon, Sep 22, 14 at 21:47

What are you recommending I spray with?
Good idea about keeping foliage trimmed. This year we had so much rain they grew so lush that I just couldn't keep up with the trimming. It's such a shame because up u it 2 weeks ago they were extremely healthy and loaded with tomatoes and not one insect or caterpillar on any of them all summer

pattio2, please see my previous message above.

Thank you Daniel_NY and all for your good advice. Now I just have to wait till next year.

Since all new infections are spread by air and in raindrops I really can't see the sense of stripping the lower part of the plant unless LB has infected plants in a previous year AND the garden is in a very warm climate where any spores dropped to the ground are protected by living tissue and could be splashed up onto the foliage.

Daniel, Daconil is not stronger than copper, it's more effective since it covers the specific attachment sites on the upper leaf surface where fungal pathogens bind. Mancozeb or copper can be a backup to Daconil if desired but are much less effective.

Your copper treated plants look fine but how do you even know that LB was a threat in your area for any specific season, including the one when that picture was taken

I've pointed out here before that Daconil has LESS toxicity to humans, pets and the environment than does Rotenone, which is organic and approved by all organic certifying agencies that I know of.

Not all organic products are without toxicity and not all synthetic products have significant toxicity.

We've been through this all before here, and I'd like to point out that daconil is THE most used effective anti=fungal in the world and has been so for several decades so there's more info about that one than any other.

No human has died of cancer, no bees, no fish, no pets.

When I research a particular product I prefer to use EXTOXNET for info and I've linked to the one for Daconil below.

Read it carefully and you'll see that with humans it's possible eye irritation that can be a problem.

read it and you'll also see that rats have been most used for studies and one can't extrapolate to humans from rat studies. That I know since I once did studies with Golden Hamsters and mice many years ago now.

In my faves I have lots of links for different garden products and as for Daconil I can find many links that condemn it and many that lay out the truth, such as the EXTOXNET links.

Below I'm linking tothe EXTOXNET Daconil link and I suggest that anyone interested read it very carefully.And pay attention to the names of Universities and government agencies that are part of the EXTOXNET newtwork.

Carolyn

Here is a link that might be useful: Daconil

carolyn137 wrote:

> Daniel, Daconil is not stronger than copper, it's more effectiveâ¦

By STRONGER I meant⦠EFFECTIVE. Sorry for my English - not my first language, as you probably remember.

> Your copper treated plants look fine but how do you even know that LB was a threat in your area for any specific season, including the one when that picture was taken

Well....I donâÂÂt know. But I never said that LB was in my garden. I simply said that I sprayed Copper, and everything looks fine. Maybe it was LB in my garden and Copper defeated it; maybe there was no LB in my garden, so Copper didn't have who to defeat.

> No human has died of cancer, no bees, no fish, no pets.

When a human dies of cancer, the doctors know EXACTLY where the cancer came from ?

> When I research a particular product I prefer to use EXTOXNET for info⦠pay attention to the names of Universities and government agencies that are part of the EXTOXNET newtwork.

So you donâÂÂt trust EPA. OK.

It looks like the EXTOXNET website is no longer updated. I didn't see any information newer than 2000. That doesn't mean any of it's information is wrong but it's always a good idea keep up to date on products that are used on food.

Daconil is Chlorothalonil which is believed to be a factor in the decline of honey bee populations. Regarding human ingestion the EPA rates it toxicity category IV, "practically nontoxic" but category II, "moderately toxic" if inhaled. Of course always follow label instructions and warnings.

EPA says: âÂÂOn September 4, 1987, the Agency classified chlorothalonil [Daconil] as a Group B2 or probable human carcinogen.â I donâÂÂt know if EPA changed their minds since 1987, but that suspicion is reason enough for me NOT to use Daconil.

Daconil - Safety Data Sheet (February 5, 2014 !)

HAZARDS IDENTIFICATION

Classifications:
⢠Skin Corrosion/Irritation: Category 2
⢠Oral: Category 4
⢠Dermal: Category 4
⢠Inhalation: Category 3
⢠Skin Sensitizer: Category 1B
⢠Carcinogenicity: Category 2
⢠Specific Target Organ Toxicity: Repeated Category 2
⢠Specific Target Organ Toxicity: Drowsiness Category 3
⢠Eye Damage/Irritation: Category 2A

Hazard Statements:
⢠Harmful in contact with skin
⢠Causes skin irritation
⢠May cause an allergic skin reaction
⢠Causes serious eye irritation
⢠Toxic if inhaled
⢠May cause respiratory irritation
⢠May cause drowsiness or dizziness
⢠Suspected of causing cancer
⢠May cause damage to blood, liver, lung, kidney, spleen through prolonged or repeated exposure.

A twofer for Daniel, then lower down for danzeb.

Daniel, the link you gave is not to the EPA, rather Syngenta, in the same business as Monsanto as to contol of millions of acres of commercial crops world wide.

Did you see the warning for tanker trucks transporting Daconil? Not really relevant for the home grower is it.

And the majority of tests carried out with rats and rabbits, which I spoke to above?

Syngenta and Monsanto are no doubt two of THE largest corporations worldwide whose customers use different formulations of Daconil as well as different pesticides. So I see that link as pertaining to their customers since it says if they have any questions to call Syngenta and gave a phone number.

Dazeb, yes I have seen reports of not just Daconil but other anti-fungals well, and certain pesticides that might be factors in Colony Collapse.

Background here is that the man who services my Monitor, a Japanese computer controlled heater, I use kerosene vented to the outside, lives in Arlingnton Vermont, has a daughter married to a man who maintains 500 hives and travels to many places to place them, especially here in the NE which is apple country.

We spoke about the possible problems and I already had a nice article on Colony Collapse from a local newspaper here in upstate NY, and I'll link to it at the bottom.

it's worth reading when considering the many known causes of Colony Collapse and those possibly involved, and what the chances are that cumulative inducers might do/

And now a link to a new problem here in the NE, this article from Essex Junction, VT, over Egg MT from where I live and VT is where the SIL with the bee hives also lives.

http://www.huffingtonpost.com/2014/01/28/zombie-bees-eastern-us_n_4683136.html

I hope those interested find something useful with what I wrote and the two links.

Carolyn

Here is a link that might be useful: Colony Collapse

I doubt the cancer toxicity from the dilute Daconil sprayed at home crops, which is washed off, comes even anywhere close to what is achieved eating a single sausage, or the background radiation you are dosed with daily from mother nature.

Anything that is going to be effective is going to have consequences. There is nothing natural about spraying your garden with concentrated copper, and I don't doubt tanker trucks of pure copper would carry similar warnings. Everything has it's pluses and minuses and needs to be looked at objectively.

Bees are becoming primary concern for me, next year we have plans to add bee theme to the plant swap and set up table for swapping on bee favorites... I have phenomenal annual which reseeds, impatiens glandulifera, great bee magnet. It is 6 feet tall and needs no care whatsoever...
Am thinking I had just about every known fungal and bacterial problem with my tomatoes but the LB.
I am not fond of Daconil, nor do I like copper. I have long standing habit of eating tomatoes off the vine...
There is no one spray that will work year from year, just as Daniel got lucky this year with copper next year could present different picture, wind direction will change, weather will be more unfavorable, really does not depend how experienced or careful gardener too... life happens...
LB is tough, so sorry you had been hit so many times.
Tania from tatianatomatobase, reports that open tunnel structure, i.e. similar to greenhouse but with 2 short sides off has been really helpful to protect from air borne problems, Tania does not use any sprays. This is the route I am considering adding to my aerated compost sprays. I do feel comfy with my microbes LOL

May I suggest that you consider getting Mountain Merit and including a few in your garden next year. Also, Iron Lady has significant tolerance. They won't totally stop Late Blight, but they will slow it down significantly and will give you more time between fungicide applications. Yes, copper is a fungicide!