hugh
Full Member
Posts: 43
Joined: Sat Aug 06, 2005 10:01 pm
Location: Boucherville, Quebec, Canada

Cucumbers

The leaves of my cucumbers have suddenly decided to die. There was a bit of a problem before but I assumed it was just the life cycle of a cucumber. But today it was rampant. The stems and the rest of the plant appears fine – well to date. I have never seen this before but I have grown cucumbers in greenhouses before. I wondered if it could be the very heavy rain we have had recently in Quebec.

Hugh

grandpasrose
Greener Thumb
Posts: 1651
Joined: Tue Jun 28, 2005 4:21 pm
Location: Quesnel, BC, Canada - Zone 4a

Can you describe what you mean by dying? Are they going limp, but staying green, or going yellow and falling off, turning brown? Need a little more to go on! :wink:
VAL
VAL (Grandpa's Rose)

hugh
Full Member
Posts: 43
Joined: Sat Aug 06, 2005 10:01 pm
Location: Boucherville, Quebec, Canada

It has changed in the last few hours – it looks it botrytis when it starts. But there is no hairy grey mould. The leaves just then die – turn brown and curl up.

There are holes in some but no evidence of insects on the surface. As I said we have had very wet weather yesterday (the tail of the hurricane) followed by a very warm day today. If it is botrytis I have never seen botrytis attack so quickly. The squash next to it has caught it as well but not so badly, the leaves are speckled with white.

Do you think I should spray or just hope the weather changes? I am a bit worried about spraying cucumbers as they are sensitive little things.


Hugh

grandpasrose
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Posts: 1651
Joined: Tue Jun 28, 2005 4:21 pm
Location: Quesnel, BC, Canada - Zone 4a

It sounds to me like you have Alternaria Blight. It is caused by the fungus Alternaria cucumerina, and infects melon, squash, cucumber, pumpkin, and watermelon. Wet weather and temperatures of 60-90 F are it's best conditions. Spots develop first on older leaves. They enlarge rapidly and turn light brown or dark brown to black. Spots on the upper leaf surface may develop rings, Rapid defoliation occurs when weather favors the disease.
I have had this on my cucumbers before, and the only biological thing I found to treat it was to spray with copper hydroxide. This did slow the blight considerably and I was able to harvest cucumbers.
Once you have harvested, ensure that all foliage and plant material is burned, and then once again spray the garden area with copper hydroxide. It is a fungus that can lie in wait for it's perfect conditions, so try to eradicate any thing left behind.
You are correct in assuming that the weather has contributed to this, and there was probably nothing you could do to prevent it.
Best of Luck! :wink:
VAL
VAL (Grandpa's Rose)

hugh
Full Member
Posts: 43
Joined: Sat Aug 06, 2005 10:01 pm
Location: Boucherville, Quebec, Canada

Thank you very much your diagnosis, it certainly fits the patient.

The draw back in our envirnmentally conscious region is that you 1) can not burn anything, 2) most garden chemicals are banned.


Does anyone know if the ban on garden chemiclas is across Quebec or our 'city'. If it is Quebec wide, where can you get a list of permitted chemicals? I have also got a problem with my apple trees that need spraying.

Alternaively should I move to Ontario.

Hugh

grandpasrose
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Posts: 1651
Joined: Tue Jun 28, 2005 4:21 pm
Location: Quesnel, BC, Canada - Zone 4a

Hey Hugh - we have the same banned products here in BC - most of them are actually federally implemented and they include the systemic chemicals like 24D, Killex, you get the idea. Copper hydroxide is not one of these. To get a complete list of the banned products in your area you need to contact your Ministry of Agriculture and ask them to send you one.

As far as not being able to burn anything - at least make sure that this material does not end up in your compost or a garden anywhere. I am not sure of the quantity of material you have, but if you have a fireplace maybe? Otherwise, I think I would be tempted to go bury it somewhere that is not going to be disturbed or used for a garden.

For your apple trees, you need to describe what is happening with them before I can tell you what needs to be done - give me a little story!

Hang in there Hugh - we all have these trials every year - it's how we learn! :wink:
VAL
VAL (Grandpa's Rose)

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