Viruses in Raised Beds

[snooger]

I created several raised beds 8 years ago and had fantastic luck the first 4 years. Each year thereafter, I've had more and more problems with viruses. Last year's harvest was terribly affected. I do use anti fungal sprays. The garden is drip irrigation. Last year I used a barrier between the soil and the above ground part of the plants to avoid having soil borne viruses impacting the plants. I'm to the point now that I'm thinking of just replacing all the soil... however it seems to me I'll still have viruses. I do not rotate crops, which may be a problem as well. I really like the crops where I put them so I'd prefer not to rotate them if possible.


Anyone else have these problems or suggestions? Digging the whole garden up to replace the soil will be a monumental task.

Thank you!

[rainbowgardener]

do you know what viruses? If it truly is a viral disease, anti-fungals won't help. And what kind of plants? If you are talking tomatoes, many varieties have been bred to be virus resistant. That may be true for other things as well, but I don't know much about it.

Here's a little article about plant virus: https://www.rhs.org.uk/advice/profile?PID=188

also

The first step to ensuring a virus-free garden is to be careful when planting and pruning. Wash your hands or gloves after dealing with each plant, as well as any equipment that was used to cut or dig. When cutting or removing diseased plants, it is best to entirely disinfect the equipment and containers properly before using them elsewhere. Try to remove weeds as much as possible, since they often act as carriers for plant viruses and tend to choke gardens. Since viruses thrive on plants that are already growing poorly, keep plants healthy by giving them enough water and nutrients. When planning a garden, don’t try to crowd too many plants into a single space since this method will almost certainly backfire. Viruses spread even faster through plants that are grown close together. In this type of scenario, the soil will also tend to have much less air, thus increasing the spread of viruses. Give each plant enough space to grow and a turn up the soil once in a while to increase aeration. Adding mulch such as wood chips or even small pebbles into the soil will also help to add air pockets. At the garden center, look for plants that are guaranteed to be free of viruses. An even better option is to seek out virus-resistant breeds of plants or seeds. Prevention of viruses is the best way to help your garden stay healthy.

If you do detect signs of a virus, there are a number of ways to start treatment. First remove the plant from the area immediately. Viruses are rarely eliminated with the use of chemical sprays. As an extra precaution, it also helps to remove the soil in the immediate area before setting down a new plant. Check the plant for insects. If you do notice that there seems to be an abundance of bugs on the plant, use a good pesticide to get rid of them. It is vital to act soon because when plant viruses become established, they spread quickly and are incredibly difficult to stop. Diseased plants should be destroyed when removed; this can be done by burning them or disposing of them in a sealed trash bag. Never use diseased plants in a compost heap, since the virus could easily be transmitted to the resulting batch of soil.

http://www.gardenforever.com/pages/gard ... iruses.htm

It is a good point in there about maybe without trying to remove all your soil (understandably a huge task), you can remove the soil just in the area you are planting something. This would be like making a planting hole, but then not putting the dirt back in it, fill the hole with some clean potting soil.

Sorry you have had this difficulty. It must make gardening very frustrating.

[snooger]

You are completely correct, an improper characterization of my problem for sure. I have problems with fungal disease not viruses. Thanks... it has been since last fall when I investigated this. The problems are fusarium and verticillium wilt. Tomatos are the worst hit, cucumbers are also hit. Peppers as well (although this may be some other problem). These are the major plantings in my garden. I have numerous other things, but these are my major crops.

I have really enjoyed the raised beds but you are right, very frustrating to see your work turn into dying and fruitless plants. I was considering solarization but it seems to me I'm too far north for that to be really effective (Chicago).

[applestar]

As far as I know, I haven’t encountered fusarium and verticillium wilt, but looking up diagnostic characteristics, the information on this page look useful:

Verticillium Wilt of Tomato fact sheet
http://vegetablemdonline.ppath.cornell. ... illium.htm

Diagnosis involves making a vertical slice of the main stem just above the soil line and observing a brown color in the conducting tissues under the bark. This discoloration can be traced upwards as well as downwards into the roots. In contrast to fusarium wilt, verticillium wilt discoloration seldom extends more than 10-I2 inches above the soil, even though its toxins may progress farther.

Also found these....

Organic-Fungicides-Veg-Crops-Herbs-Efficacy

Some selected fungicides for use on herbs - CT Integrated Pest Management Program
http://ipm.uconn.edu/documents/raw2/htm ... play=print

[snooger]

I've read the articles (I tend to dig quite heavily into studies) and this always helps some. BTW, include Anthracnose in my list of problems. I have used fungicides (multiple), and they do help, but it is typically marginal.

So, my original thought was to replace the soil, but my instinct tells me that I'll never get "all" the soil and so even this won't solve my problem. The other thought was solarization this summer. I was planning on just planting a container garden this year and put plastic down in late June.

Regardless, I'm not confident I'll have luck with either of these strategies. I like the idea of digging out the hole for the plant and just replacing good soil in that spot. If I do that and mulch around the rest of the bad soil, it may help some this year. Inevitably I'm not sure I can rid my beds of these problems in the long run.

[applestar]

I like to alternate actual fungicidal remedies like baking soda, drop of oil, etc. with phylo- and rhizo-sphere biological competitors like milk/yogurt/whey solution and diluted AACT (actively aerated compost tea) sprays.

[rainbowgardener]

That is good news though. Fungal diseases are actually treatable; viral diseases are not. Baking soda, hydrogen peroxide, and diluted milk are fungicidal treatments. Cinnamon is also a natural anti-fungal, but is not good for the plant leaves. You can mix some cinnamon powder into your soil. Since you know you have had these diseases, start treating the plants right away as soon as you plant them. Prevention works better than treatment. You can't mix treatments, but you can alternate them. Spray the plants all over (including undersides of leaves) at least every two weeks.

Also space your plants with plenty of room for air circulation, never water the leaves, just the soil. I prune my tomato plants just enough to be sure there is air circulation to the interior of the plant.

There are tomatoes with bred in resistance to the wilts. Look for resistant varieties.

Best wishes! Let us know how it all works out for you.

[DarrenP]

As has been suggested, plenty of air circulation around your plants will help minimise fungal diseases. As well as any fungicides, look into companion planting. Not only does it help with pest control, it also helps with fungal disease.
Famous last words I know, but I have yet to experience any fungal disease or any major pest problem, and I mix my beds up with all sorts, as well trying to rotate crops. The main crops to rotate are your brassicas and your solanacae (tomatoes, potatoes, etc).

[snooger]

Thank you everyone for the advice. I now have a lot more alternatives at my disposal. Interestingly the spacing issue came up a few times. My tomato plants are so full (when they are not dying off), that they form a hedge. Maybe the strategy is also to plant half as many? Time to make a new bed!!

[imafan26]

I don't have too much fusarium or verticillium but I do get mostly late blight and mildew since I live in a hot climate. Sanitation is important as well as selecting suitable varieties that are disease resistant. It does mean that I often have to settle for less than spectacular tomatoes but they still taste better than the market varieties. The spores of some fungal diseases are floating around in the air and hard to totally avoid.

However, the conditions for fungal diseases to take hold are the same.... warm humid conditions.

You will rarely see fungus on the plants when it rains almost continuously for weeks but within three days after the rain stops and the humidity increases from all the water evaporating off from the ground, that is when fungal conditions take hold. It is important to start an antifungal spray program as soon as the rain stops and to repeat it if you have light rains between. While it is raining, the rain washes off the fungal spores before they can take hold, it is when the humidity rises and the spores are still sitting on the leaves, when the plants are vulnerable. Sometimes no matter what I do, I can't keep the fungi off and I end up pulling the plants, waiting for dryer weather and starting over.

Plants that are most susceptible will be plants that come from dryer areas and have leaves that are hairy or fuzzy. These plants are designed this way to actually capture moisture, but it is a problem when they are in a wetter environment. Sometimes, if you can wait, it is better to move the plants out when the weather is dry. The alternative would be to actually keep the plants wet and keep washing off the spores, but I haven't been able to keep them wet long enough to get past the humidity without having issues form the soil being too wet.

Sometimes, I have had to rotate fungicides. It is important when using sulfur or oil not to use them within a month of each other or they will burn the plants. If I know the rain is going to last awhile, I usually will go with an oil as a preventive since it helps the plant shed water and does not wash off like sulfur. If it is really humid, I might add a second fungicide like chlorothalonil or even cinnamon, potassium bicarbonate + horticultural oil, or milk.
https://attra.ncat.org/attra-pub/viewhtml.php?id=126
https://njaes.rutgers.edu/fs547/
https://plantpathology.ca.uky.edu/files/ppfs-gen-07.pdf
https://pdfs.semanticscholar.org/8140/3 ... eed8f5.pdf

[MockY]

The way I try to combat Fusarium wilt and root rot nematodes is by crop rotation. In between plantings, I completely fill the bed with Garlic. After such a long period, at least most of the nematodes have starved as they don't care all too much for garlic. As a result, I've noticed I don't get hit by Fusarium wilt anymore in the plantings directly after the garlic.

And one can't have enough garlic, right?