What is doing this? It kills them dead, it did it last year and its doing it this year, too. I hardly see any bugs on them, but they just die.

It is quite advanced, as in leaves are gone already, it could be anthracnose.
Cucumbers can be easily affected by various pathogens, like fungi, bacteria.

It's Cucumber downy mildew (CDM): if you live on the US East Coast unfortunately it's a very serious problem and it's slowly spreading inward.

You should plant a CDM resistant cultivar lick Brickyard or Bristol. Fungicides are effective when used either in the early stage of the disease or preventive: note that while some are extremely effective against CDM (propamocarb for example) they may be hard and/or very expensive to obtain, especially during crop season. Mancozeb is fine to use at higher dosages but only as a control measure.

Thanks ElPolloDiablo! How sure are you that is indeed CDM? I was doing some looking, and seemed to me that CDM was generally a nuisance, but would not typically kill your cucumber plants. This stuff is absolutely killing them, and fast. I thought it might be bacterial wilt? But that is apparently spread through squash beetles, and I have not seen any of those...

Thanks!!!

Homeslice said:Thanks ElPolloDiablo! How sure are you that is indeed CDM? I was doing some looking, and seemed to me that CDM was generally a nuisance, but would not typically kill your cucumber plants. This stuff is absolutely killing them, and fast. I thought it might be bacterial wilt? But that is apparently spread through squash beetles, and I have not seen any of those...

Thanks!!!

In 2004 a new Cucumber downy mildew strain was first isolated in New England and has since spread to the whole East Coast and has been spreading Westward since: this month it was discovered in Michigan already.
This stuff is not your ordinary Downy mildew: it spreads very fast on the plant and once it has affected enough leaves, messing up the chlorophyll cycle, the plant will die. It's considered a major agricultural disease for very good reasons.

I had to deal with bacterial wilt on cucumbers and melons in the past: your plants' symptoms are not consistent with it. Basically it starts out with leaves wilting for no reason during the day and recovering in the evening around sundown. Then some leaves (but not on all cultivars) will get large papery spots and finally the plant will just wilt and die for seemingly no reason. It's incredibly frustrating until you understand what the problem is.

How do you differentiate anthracnose from downy Downy mildew on cucumbers when the leaves do not have the typical white layer one would expect for mildew?

ElPolloDiablo said:

In 2004 a new Cucumber downy mildew strain was first isolated in New England and has since spread to the whole East Coast and has been spreading Westward since: this month it was discovered in Michigan already.
This stuff is not your ordinary Downy mildew: it spreads very fast on the plant and once it has affected enough leaves, messing up the chlorophyll cycle, the plant will die. It's considered a major agricultural disease for very good reasons.

I had to deal with bacterial wilt on cucumbers and melons in the past: your plants' symptoms are not consistent with it. Basically it starts out with leaves wilting for no reason during the day and recovering in the evening around sundown. Then some leaves (but not on all cultivars) will get large papery spots and finally the plant will just wilt and die for seemingly no reason. It's incredibly frustrating until you understand what the problem is.

Wow ElPolloDiable, when I read your first post, I read it quickly, and thought you said powdery mildew, since I had that before and read about it many times and cured it with a baking powder stray no problem. So I started doing more research, and I came to the conclusion it was downy mildew. Then I came back here and found that is what you said it was in the first place. So you nailed it, thanks so much!!!

From what I can tell, Daconil is the best way to beat it, does that sound right? I don't care if its a chemical spray, whether it is organic or not, none of that jazz matters to me. I just want to keep my cucumber plants from dying! This downy mildew is horrible, horrible stuff. Even plants I planted a few days ago in a separate small pot are getting hit with it and dying. :(

Thanks!!!

PaleoTemp said:How do you differentiate anthracnose from downy Downy mildew on cucumbers when the leaves do not have the typical white layer one would expect for mildew?

Don't know about anthracnose, but for downy mildew the leaves have no white layer on them. They start turning yellow/brown, then full brown, and all parts of the plant die off in short order.

Bump!!!