How can I fix my soil so my beans and cukes stop getting diseased?

[adeledamate]

I have planted many types of (organic and non gmo) string bean and cucumber plants and seeds for the past four years. I have boxes/raised beds and have tried planting in different ones every year with no success. The plants start off beautifully, I pick one nice harvest then it's down hill from there. First there's a couple of yellow leaves, then small fruits that dry up and fall off, finally in the end, the rest of the leaves start turning yellow. I've done some research and the pics I've found look just like wilts that cukes and beans get. So.....I just finished pulling up my almost dead plants, which are next to healthy corn and squash plants and decided to see if there was a way to mend my soil. Is it possible to kill the viruses that keep infecting my plants year after year? Can I plant herbs that will help the soil get rid of the viruses? I love string beans and cukes and am so frustrated with this happening every year. Should I give them up for a few years? Any suggestions would be very, very welcome.

 

[OaklandCityFarmer]

You know to get really good soil that can put up with some crazy diseases takes time.

There are some things you can do though. I recommend:

1. Always destroy diseased plants and do not compost them.

2. Solarize your soil for at least 4-6 weeks and at least twice with a tilling and 2 weeks in between.

3. Add beneficial nematodes to help kill off bad ones.

4. Use a good blend of cover crops over winter (I know that's a loose term in most of So Cal) and till them in.

5. Increase organic matter. This will also help improve earthworm populations.

There are many others but here's a good start.

What disease is affecting your plants?

 

[Tutter]

Have you tried bringing in soil for a raised planter area, and see how they do with foreign soil? Sometimes it can become contaminated, sometimes not.

Did I once hear you say that you were in the Los Feliz area? That would be anywhere from Western, to what, Brand or so? Which end are you on? I ask because I grew up in the area. (In the hills.)

 

[adeledamate]

Thanks for the great tips Oakland. You truly are a treasure trove of information. I have been very careful with the diseased plants and put them in the garbage for fear of spreading the disease. I have not tried solarizing and will definitely do this. Is it o.k. to do at the end of this season? I had been planning on planting a cover crop this year, of course now I'll do it after the solarizing. I have a great worm population but will continue to add my finished compost.
Now, as far as the diseases go, I am only guessing what they are by looking at pictures on the internet and my two books, Sunset Western Garden Book and Rodale's Organic Gardening. My guess is either a bacterial wilt or a mosaic virus. I know they are supposed to be spread by beetles but of all the years I've lived here I haven't seen one beetle. I did see some aphids but they were attached to the corn. Which is why I think it is something in the soil, which I guess would make it some other disease. I wonder if I could take the plants somewhere to get them tested? I would so love to be able to grow cukes and beans. I know other people around here have really good luck with them.
Thanks again for the wonderful advice.
Here are some pics of two that I left in hopes that they might miraculously survive. The bottom two pics are of a cuke growing next to a volunteer tomato plant.

 

[adeledamate]

Have you tried bringing in soil for a raised planter area, and see how they do with foreign soil? Sometimes it can become contaminated, sometimes not.

Did I once hear you say that you were in the Los Feliz area? That would be anywhere from Western, to what, Brand or so? Which end are you on? I ask because I grew up in the area. (In the hills.)

Hi Tutter: Yes, I have brought in new soil (from a nursery) and tried plants in the planters, but these too ended up getting diseased. I thought I might have spread the disease with infected trowels or my hands.
Yes, I live in Los Feliz. I live south of Los Feliz Blvd. Just one block south of Franklin Ave.
Near Commonwealth. Did you go to school here? My oldest son goes to Marshall and my younger one goes to Franklin Elem. My husband has lived here his entire life. LA is definitely an interesting place to live. I've been here for the past 12 years and still feel like a small town girl. Not sure if I'll ever get use to the pace.

 

[Tutter]

Oh yes, I was born and raised there! :coolsun

I do know their schools, but I went to Cherimoya Elementary School, west of you. Then Le Conte Jr. High, which has changed markedly. My dh, who also was born and raised there, went to different schools yet, but at that time they had busing for integration, so he didn't go to the schools in his district.

Where you are, there used to be a cute little bakery, where all my young childhood birthday cakes came from, and an older library. The bakery smelled wonderful; is it still there?

I can imagine how different it must feel for you. Things used to be different, though, believe it, or not. Being that your dh never left, he might not have noticed it as much, but there have been some really big changes, which my parents, sister, friends etc. tell me about. Actually, it had already changed quite a bit when we moved.

How nice to meet someone from so close to my old digs!

 

[OaklandCityFarmer]

Thanks for the compliment!

So there are a couple of tests you can do to see if it is bacterial wilt, they don't always work but they might help.

Cut 2 pieces of the infected plant (if you still have them) stick one piece in a glass of water completely covering it. Wait a few hours and if you see some whitish milky stuff coming out of the ends, it's bacterial wilt. With the other piece, squeeze it. A gooey ooze should start coming out that is very sticky, this is another indication of bacterial wilt.

Now with mosaic viruses, aphids can spread them as well. That's good news, so now you know one of the culprits and bad news in that you may have a serious infestation. I would use a soapy water solution for aphids. I also read somewhere that a 1 part milk to 5 parts water will work against aphids as well. If this is true, great news, since a milk solution will help protect against powdery mildew in cucurbits.

Yes, you can solarize at the end of the season. We do. Then plant the cover crop. Also you might want to try to establish a lady bug population to help with the aphids.

Good luck!

 

[adeledamate]

Tutter:
We have some students at Franklin, I teach at Franklin as well as having my son attend, that come to Franklin instead of Cherimoya. From what I hear Cherimoys is not as good as it use to be. Hopefully it will get better.
Do you remember what street the bakery was on? We have a donut shop close by and lots of very cute cafe type restaurants but no bakery.
Where do you live now? I was born and raised in northern Cal. How funny that we switched places.

 

[adeledamate]

Thanks Oakland. I'll try the two ideas to see if it is bacterial wilt. I did some more research after I pulled up one of the plants. The roots were covered in all of these little nodes. It looks like I have nematode root knot. I think that's what it was called. I'll have to check that site again. I will definitely be solarizing my soil. I found a great website that explained how to do it and it actually seems pretty easy since I have boxes. I have a big roll of painter's plastic covering that I think will work well. I have some volunteer tomato plants and 4 pumpkin plants left in the boxes. It looks like the pumpkins have leaf miners. Should I just pull everything out and solarize now? What a disappointment.

 

[OaklandCityFarmer]

Thanks Oakland. I'll try the two ideas to see if it is bacterial wilt. I did some more research after I pulled up one of the plants. The roots were covered in all of these little nodes. It looks like I have nematode root knot. I think that's what it was called. I'll have to check that site again. I will definitely be solarizing my soil. I found a great website that explained how to do it and it actually seems pretty easy since I have boxes. I have a big roll of painter's plastic covering that I think will work well. I have some volunteer tomato plants and 4 pumpkin plants left in the boxes. It looks like the pumpkins have leaf miners. Should I just pull everything out and solarize now? What a disappointment.

I'm sorry that things didn't turn out as well as you hoped. There's always next year. You could solarize now if you'd like. This might give you a chance to plant a fall crop in one of the boxes? How's your microclimate there? We used to grow some plants year around in Newport Beach. At least that way you can have something in the ground while your working on your other boxes. Just a thought.

What cover crops are you planning on using? Barley, oats, annual ryegrass, wheat and a few others have been known to hinder the progression of nematodes in the garden. Also, you should check out about purchasing and applying some commercially available beneficial nematodes for after you solarize.