fusarium wilt

[Orang3]

There is so much useful information in this thread. Thought it might be good to summarize b54red's experience against fusarium. If i missed something or if something is incorrect please let me know. Or you can update the spread sheet.

Originally Posted by b54red

Since the bleach is so reactive my biggest worry is that I may get too many salts as a result of the bleach's chemical reactions to things in the soil.

Have you tried using Clearex flush? Raybo uses it for his earthtainer to remove salt build ups. Not sure if it will work with bleach though.

[z_willus_d]

Originally Posted by b54red

Naysen, if I saw the yellowing you show in your pictures I would immediately think early stage fusarium. Sometimes the first sign of fusarium will be a slowing in growth. One of the reasons I have been picking so many small fruit off of the sick plants is the growth just slows to almost nothing and by the time the plant totally wilts the fruit will still be smaller than normal. I don't pull plants with fusarium til they totally wilt or if they are still very small and showing advanced symptoms with only very small fruit on them. Marla is right about cutting one of the stems that has a lot of yellowing leaves. If you see the dark vascular tissue it is usually a confirmation of fusarium. Plants with fusarium will tend to yellow faster once hot weather arrives and heavy rain will only speed up the process for some reason. I will try to go out today and cut some stems and take some pictures to show you what to look for.

I think it was your second pick that looked a bit like Gray Mold but it is a little hard to tell in the photo. I can say it seems to hit black tomatoes first and hardest. I wouldn't think it would be a major problem in the drier climate you have in California. It is almost always worse here during times of heavy or frequent rains and very high humidity. The bleach spray is the only thing I have found that is helpful with it and it is only effective if you spray early in the disease cycle before it infects most of the plant.

Ok, I'll try and identify a vine to sacrifice this weekend -- it will be hard to choose. You're right, that 2nd pic was of one of the plants not showing the yellow leaf symptoms, but it does seems to have something else, perhaps Gray mold. Good eye.
-naysen

[Mlm1]

One more way to combat fusarium that is not on the list is to graft the heirloom onto a rootstock that has fusarium tolerance. I have been grafting onto Maxifort and Beaufort for the last few years. Both of these rootstock have tolerance to fusarium race 1 and 2 as well as tolerance to TMV, nematodes, verticillium, corky root rot, and fusarium crown and root rot. I have given the plants to 2 people that I know had fusarium. I had seen their gardens and had cut up their stalks and discussed it with a plant pathologist. I tried both grafted and ungrafted plants in the fusarium infested soil and the ungrafted were unhealthy and slowly died and the grafted were monstrous plants covered in tomatoes. The difference was truly amazing. The grafting is not difficult. I keep some of the grafted plants in my own garden both in ground and in pots and I do find them to be vigorous and productive but not a huge difference between them and my ungrafted plants so I don't know if it is worth grafting if there are no disease problems. I graft because i like doing it and I am always on the lookout for a good use for the grafted plants. Most likely I will have extra grafted plants next spring and would be willing to send them to a few growers that know they have fusarium or verticillium to see how they do. So if any of you that have been posting about your fusarium want to try them pm me and maybe next year we could have some test gardens with the grafts. It would be very interesting.
Marla

[b54red]

Naysen, you don't have to cut a whole plant just one stem that is affected. It does usually need to be bigger than a pencil in thickness in order to clearly see the fusarium symptoms.

[z_willus_d]

These are all pretty much pencil sized, but while I was out watering the work garden this afternoon I figured I snap a few dead branches and snap a couple pics. My work vines aren't as bad (far along to towards the end) as my home, but they seem to be exhibiting much the same conditions. Maybe these pics don't tell much. Maybe they don't prove much for or against Fusarium ID.
-naysen

[b54red]

Naysen, it looks like the 5th and 6th picture might be showing signs of early fusarium. Below is a stem that I cut showing definite fusarium syptoms. It is quite easy to see the advanced darkening in the lower left side of the cut stem.

[rnewste]

Marla,

Thank you very much for your kind offer of the grafted tomato plants. I would certainly like to trial a few in my EarthTainers next year to do a semi-clinical evaluation of their disease tolerance vs. ungrafted varieties.

Naysen, as Marla is in NorCal, you should also take her up on this wonderful offer.

Raybo

[Mlm1]

That's great Raybo. I'll pm you this winter and we'll work out the details. Naysen and I have been in contact and I think he plans to practice grafting this winter and will plan to graft his own next spring although he knows he is welcome to get some from me. It will be nice to see the grafts go to good use.

I'm not totally convinced of the fusarium in Naysen's picture. All of the fusarium infected plants I have seen looked more like this picture although I recognize b54 is really an expert in this area so it may be.
http://www.ipm.ucdavis.edu/PMG/F/D-TO-FOXL-ST.004.html

Marla

[Sun City Linda]

Mim1 - Do you get the seed for the grafting stock from Johnnys, I think I may have seen it in their catalog. Sounds like something fun to fool around with.

[nctomatoman]

Here's where I see where even grafted plants could run into trouble. and this is just based on my observations. I lose plants to Fusarium each year - it made sense in the big garden - the soil was infected and the disease went to the plant through the roots.

So then I moved to clean pots - either new ones, or if used previously, washed well with bleach - and used new potting mix each year. I also mulch well to keep soil off of the lower leaves.

Anyway - each year I continue to lose some plants to Fusarium wilt. My suspicion is that there must be an insect vector for my plants in pots to become infected - something will feed on/chew on an infected plant in another garden - then visit my plant and infect the plant.

What do people think - I guess the only way to test this hypothesis would be to graft all of my seedlings into disease tolerant rootstock, plant them in bleached pots with sterile mix....if some of the plants still come down with F, the insect vector is the only one I can think of.....thoughts?

[Mlm1]

Originally Posted by Sun City Linda

Mim1 - Do you get the seed for the grafting stock from Johnnys, I think I may have seen it in their catalog. Sounds like something fun to fool around with.

Yes I get it from Johnny's. I have used all of their rootstock seed. My favorite for Sacramento is Maxifort. For northern climates (for my family in Montana) I use Beaufort. It is a fun project and it's over before the real work of the summer gets going.

Marla

[Sun City Linda]

Thanks Marla. I think I will get some rootstock and give it a try!

[z_willus_d]

I'm anxious to read the responses to Craig's posit/query. Maybe it's the engineer in me, but I just don't handle open, uncontrolled systems so well. I like to understand and control the variables. I have this glimmer of hope that I might be able to achieve this with the grafting and and also some way of controlling the pest vectors, either through a well structured, organic spray regiment or complementary ecosystem control (beneficials, healthy soil, good floral/fauna, etc.). I'll start with the grafting trials this winter. I should have some questionable, not so pure, definitely contaminated soil-less grow medium from my now outdoor InnTainers. Maybe I'll purify two of six and load with all new media for control.

Marla, have you encountered Fusarium in garden? I believe you wrote "yes, in the past." If so, what did the stem cross-sections look like? More like mine, or the UCD pic? Of course, my pic was only of a branch of pencil diameter, not a main stock.

Thanks,
Naysen

[Heritage]

Originally Posted by nctomatoman

What do people think - I guess the only way to test this hypothesis would be to graft all of my seedlings into disease tolerant rootstock, plant them in bleached pots with sterile mix....if some of the plants still come down with F, the insect vector is the only one I can think of.....thoughts?

Fusarium infects the plant through the roots, so you are possibly getting cross contamination from nearby soil or even through the holes in the bottom of the pots (if sitting on infected soil/surface). I suppose it would be possible for some soil insect (like fungus gnats) to spread the fungus among containers but I don't know.

Grafting plants onto F tolerant rootstock would give plants a better chance of producing a crop in infected soil but wouldn't stop the fusarium completely.

Fusarium is also a seedborne disease, so seed could be a source of infection - especially in the seed trading community. I usually treat any seed from other sources for 2 min. in a 1:5 sodium hypochlorite/water bath (followed by a rinse) just before seeding.

Steve

[Mlm1]

I didn't think fusarium could be transferred by an insect vector. I agree with Steve and would add that it is transferred on all equipment (shovels, clippers, gloves, stakes, pots), as well as shoes. Anything that comes into contact with the infected soil or plant could carry the fungal hyphae or spores to a new area. I can imagine that wind could blow infected soil to a new area.

Yes Naysen I have seen infected stems and they looked like the UCDavis picture so although B54 may well be correct I think it is still possible you don't have fusarium. If you have to remove any plants be sure and check the stems. Either way the grafting will be a fun winter project.

Marla