Unexplained sudden wilting 3 year old Merlot

[vtoddw]

Hello,

I have a 3rd year Merlot vine in a row of 6 Merlot vines that has sudden wilting on the cordon but the growth from the roots is fine and healthy. None of the other 24 vines have this problem, it was growing fine until last week all the shoots and leaves became limp and turned upside down. I've verified the irrigation is flowing fine on this vine, same as the rest. Only difference is there is a lot of Bermuda grass around the base. Is it possible this is all due to the nutrients / water the grass is stealing? Or could it be a disease, like verticillium wilt?

Here are some pics showing the wilting, the healthy growth at the base of the vine and the neighboring vines which look fine.



Thanks in advance,
Todd

 

[balatonwine]

I had a vine do that once. Base had healthy shoots, but those at the wire were got limp in a week.

Found a big fat wood boring beetle grub in the main stem.

Not saying this is your exact issue, but if you have some healthy lower stems, may be wroth to just cut off the current main stem and try to retrain a new stem from the lower healthy ones. If those also die off, then the vine may simply die. They do that for many reasons. I have a few thousand vines, and every year a few simply die.

 

[vtoddw]

I had a vine do that once. Base had healthy shoots, but those at the wire were got limp in a week.

Found a big fat wood boring beetle grub in the main stem.

Not saying this is your exact issue, but if you have some healthy lower stems, may be wroth to just cut off the current main stem and try to retrain a new stem from the lower healthy ones. If those also die off, then the vine may simply die. They do that for many reasons. I have a few thousand vines, and every year a few simply die.

Thanks very much for the reply. Yeah this vine never had very good vigor and I don't much like the structure so I was planning on cutting off the trunk since I saw the wilting and letting both (or one) of those become the new trucks (I've had better production with vines that have dual trunks than a single trunk, not sure what that's called). Unfortunately since I only have 30 vines I fret at every single vine death, which has been about 1 per year for various reasons.

I appreciate your suggestion, I'm wondering if you can advise whether or not I should cut the trunk this time of year or wait for dormancy in the winter. I've never actually cut any trunks or cordons during the growing season, only new shoots, so I just don't know if the bleeding will harm the vine.

 

[balatonwine]

Unfortunately since I only have 30 vines I fret at every single vine death, which has been about 1 per year for various reasons.

Understand. I have the same for my 30ish tomato and pepper seedlings I raise from seeds each year. I also fret over those I loose.

I'm wondering if you can advise whether or not I should cut the trunk this time of year or wait for dormancy in the winter. I've never actually cut any trunks or cordons during the growing season, only new shoots, so I just don't know if the bleeding will harm the vine.

I can not advise. I do not have enough facts to advise to provide a complete cost benefit ratio.

But personally, simply if it were my vine, I would cut the vine now. For any of the following thoughts:

1) If a disease, it may have come in from a sap sucking insect. Thus maybe not fully worked its way down the stem. So major surgery now may be like cutting off a limb of a mammal affected from gangrene. Stops the spread of the infection. Lots of blood loss, a limb lost, but saves the body.

2) Plants deal with major injury better than we give credit to. While there are best practices for when and how to trim, they can be actually quite variable. Cutting late in the season often is frowned upon for some incorrect reasons. The main reason is that the plant will loose some vigor from some sap loss, and for commercial reasons such lost vigor is to be avoided. But sap loss is really not that big an issue for plant health as most suspect. It is more an issue for vigor. Plants have mechanisms to deal with damage. In fact, cutting too soon in the season may be worse than cutting too late. Sap bleed out is simply one method assisting the plant to avoid infection of the wound. To help the plant simply do not make major cuts if you expect rain within 10 days post cut. In that time frame the plant should have sealed the wound enough to get along without risks. But, yes, that sap loss does affect the vigor and strength of the plant. If I do major cuts on a spring plant, I nip off all fruit that year. Gives the extra energy lost from the cut to heal rather than trying to make fruit.

3) Better to find out now, this year, if the vine will make it or not. Let it tough it out now. And if it can not cope, you can replant this fall. If you try to baby it along all this year, and loose it next year, you actually loose a year or more of production of the eventual new vine you had to buy anyway.

Hope this helps

 

[vtoddw]

That helps immensely. I was thinking along those lines as well, if I wait until dormancy then chances are the plant will die by next spring and set me back yet another year, so I might as well take the risk now.

I went ahead and cut it, first at about the middle of the trunk, then noticed there's no sap oozing so cut it progressively further down until I ended up reaching the base, and no sap. Seems like this plant isn't even pushing water up at the base of the vine.

Here's a pic before I cut it, as you can see all foliage on the cordon is dead and dried up completely, but the lower growth coming from the ground looks very healthy.

And here's another pic showing the stump left after cutting it. I cut the trunk and cordon up into small pieces to see if there was any evidence of fungus ,worms or beetles but found nothing obvious, so this is still a mystery. I'll be sure to update this post when any noteworthy changes occur as it may help someone at some point, although all I have now are more questions than answers...

Thanks again for your help, I really appreciate it!

 

[Fox Squirrel Vin]

That helps immensely. I was thinking along those lines as well, if I wait until dormancy then chances are the plant will die by next spring and set me back yet another year, so I might as well take the risk now.

I went ahead and cut it, first at about the middle of the trunk, then noticed there's no sap oozing so cut it progressively further down until I ended up reaching the base, and no sap. Seems like this plant isn't even pushing water up at the base of the vine.

Here's a pic before I cut it, as you can see all foliage on the cordon is dead and dried up completely, but the lower growth coming from the ground looks very healthy.

And here's another pic showing the stump left after cutting it. I cut the trunk and cordon up into small pieces to see if there was any evidence of fungus ,worms or beetles but found nothing obvious, so this is still a mystery. I'll be sure to update this post when any noteworthy changes occur as it may help someone at some point, although all I have now are more questions than answers...

Thanks again for your help, I really appreciate it!

That's really strange.

 

[VinesnBines]

It looks like it has died back to the ground. These are on their own roots correct? Otherwise you have healthy rootstock.

 

[vtoddw]

Yup, none of my vines are grafted, for whatever reason here in Temecula CA the nurseries don't sell grafted vines. It has dawned on me that this could be phyloxera, but the puzzling part is that there was no evidence of that above ground, the leaves looked normal until they went limp and started drying up, no bumps or anything. The other puzzling part is that the 3 shoots coming out or the ground are very healthy and growing vigorously. I've never encounter phyloxera before in the 8 years I've been growing grapes, so im not sure if this fits the pattern.

 

[VinesnBines]

I thought of phyloxera but like you, I don't have any experience.

 

[vtoddw]

I decided that salvaging one vine is not worth losing the whole vineyard, so the only way to be 100% sure was to dig it up. The good news, is that there is no sign of Phyloxera on the roots that I can tell. The bad news is that the Bermuda grass which has invaded my yard and was growing around the base of this particular vine appears to be weaving it's roots in between the vines. So my theory here is that the Bermuda grass was just stealing too much of the water and nutrients for the Merlot to support it's trunk. That still doesn't explain the healthy vine growth coming from the base, but I don't really know what else it would be at this point.

Here are some pictures showing my findings. As you can see the straw-colored Bermuda grass roots are weaving themselves right through the dark vine roots and there's no visible evidence of the beads that appear on the vine roots (at least form what I could find online).

Thanks to all for you help and feedback, I feel better now knowing that (as far as I can tell) I do not have a Phyloxera infestation.

 

[VinesnBines]

According to my Vinesmith chart, Mad Dog Plus herbicide is best for Bermuda grass. The active ingredient is glyphosate but a more active formulation than Roundup. Since the vines are three years old there should not be a problem spraying around the trunks. Glyphosate won’t hurt the vine as long as you keep it off the leaves. I suggest killing out the grass ASAP.

 

[vtoddw]

Thanks again, that's definitely the plan. I have actually been using Ornamec 170 this year, which has successfully killed it in many other spots in my vineyard, but I held off on treating this particular vine because that new growth coming from the ground was surrounded by the grass, so I was concerned about overspray. I actually just treated it last week with Ornamec 170 finally, since the growth at the base had reached a couple of feet above ground (I temporarily put a bag around the new shoots while spraying), so it's possible it would have been ok.

If the Ornamec doesn't do the trick I'll definitely consider Glyphosate, although I'm admittedly apprehensive about using it ever since Roundup got linked to Cancer....but I imagine the Ornamec causes cancel as well and we just don't know it yet, what can ya do...

 

[VinesnBines]

According to the chart Fluazifop-P-butyl the active ingredient in Ornamec is as good as glyphosate. And yes, they just haven’t been sued yet.
Paraquat is the newest evil. Oh well.
Good luck, wipe out the Bermuda grass and hope no other vines are affected.

 

[Fox Squirrel Vin]

Dicamba is the one you really got to watch out for.

 

[vtoddw]

According to the chart Fluazifop-P-butyl the active ingredient in Ornamec is as good as glyphosate. And yes, they just haven’t been sued yet.
Paraquat is the newest evil. Oh well.
Good luck, wipe out the Bermuda grass and hope no other vines are affected.

True true, thanks again, hopefully my learning experience here helps someone avoid the same setbacks in the future. In short, kill those dang weeds!

 

[Fox Squirrel Vin]

Looking at your root pictures a bit closer.. there looks to be some nematode damage on the smaller roots. That 3201 photo, the lower roots near the bottom of your hand.. those yellowish bumps look like nematode damage to me...

I've edited my previous post, this is a product that works on them and is approved for grapes. Believe it or not but that's actually a good price for a product that is effective against nematodes.

https://www.keystonepestsolutions.com/movento-insecticide-1-quart-904

 

[vtoddw]

Looking at your root pictures a bit closer.. there looks to be some nematode damage on the older roots. That 3201 photo, the lower roots near the bottom of your hand.. those yellowish bumps look like nematode damage to me...

Bad thing about those guys is there are very few treatments for them and the one there is that seems to work is $1,300 a GALLON. I don't believe it comes in a smaller quantity.

https://www.keystonepestsolutions.com/velum-prime-fungicide-nematicide-1-gallon-937

Wow, I hope not, that's extremely steep. I'm hoping that was just an optical illusion. Here's some cleaner pics without the dirt and Bermuda grass roots.

 

[Fox Squirrel Vin]

image 5102.. Nematodes usually affect the smaller roots and the cause those segmented bumps. I can't tell 100% without them in front of me but something seems a bit off on those roots. There also seems to be little root growth for a vine that size but that can be due to soil fertility, available water, and fertilizer use.

I edited my previous post with a different product that is cheaper but may not be approved in your state. It is however approved for use on grapes. I completely forgot about it and it is a product I have used before mainly as a systemic insectacide on potatoes. It's a great product and works on phylloxera as well. Not saying you should use it, but this summer, if you have more issues, it might be worth looking into and if you do have another vine die, send it to your local ag extension office for testing. FYI, the OMRI approved products for controlling nematodes don't work. Maybe in a lab in a dish but I've never had any luck with them.

 

[vtoddw]

image 5102.. Nematodes usually affect the smaller roots and the cause those segmented bumps. I can't tell 100% without them in front of me but something seems a bit off on those roots. There also seems to be little root growth for a vine that size but that can be due to soil fertility, available water, and fertilizer use.

I edited my previous post with a different product that is cheaper but may not be approved in your state. It is however approved for use on grapes. I completely forgot about it and it is a product I have used before mainly as a systemic insectacide on potatoes. It's a great product and works on phylloxera as well. Not saying you should use it, but this summer, if you have more issues, it might be worth looking into and if you do have another vine die, send it to your local ag extension office for testing. FYI, the OMRI approved products for controlling nematodes don't work. Maybe in a lab in a dish but I've never had any luck with them.

That's a much more feasible price, I'll give it a shot because at this point it's really a guessing game. I looked up the various nematodes that affect grapes and it looks like there's 7 different species, not all of which would cause the Galls I was expecting to see: https://www2.ipm.ucanr.edu/agriculture/grape/nematodes/

The scary part is that it says on that site "Every precaution should be taken to exclude plant-parasitic nematodes if the area is free of them; once established, nematode infestations are permanent". I'm hoping Movento will prove that to be untrue.

I see what you mean by the banding in that photo. I have actually had about 1 unexplained vine death per year over the last 3 years, although about 20 ft away from this vine. I've also had a lot of stunted shoots on my zinfandel vines, plus leaf burning in September and October. 2020 was actually my first harvest I used for making wine, then 2021 my harvest was half the yield of 2020. I had previously chalked up the vine deaths, leaf burning, stunted shoots and lack of yield to mistakes I'd made with watering. Now I've got my watering down and I'm inspecting the vines daily to look for hanging or burned tendrils to ensure I don't underwater on the really hot days we get out here. The last two Labor days it hit 112 and 115 respectively.

I started thinking this year that the leaf burning may be more possibly due to Pierce's disease as I did see a sharp shooter in my vines in the last month. I've only seen one or two of them, they are very fast and hard to get a close up picture of them, so I can't really tell if it's a Smoke Tree or Glassy Winged sharpshooter based on it's head pattern. It doesn't help that my neighbor has a massive lemon tree and apparently those things love to overwinter in Citrus.

Here are some pictures of 3 of my Zinfandel vines last year, not sure if this is Pierce's disease, vine stress due to lack of appropriate watering / nutrients or if it's possible due to Nematodes all along. I did lose one of these that looked very healthy last year, it went into dormancy winter of 2020 looking fine and then when I pruned it during the spring of 2021 the entire vine was hard wood all the way tot he ground. I feel like this leaf burning didn't start happening until Summer of 2021 but I only started taking pictures last year. Oddly enough the only vines I've seen with the leaf burning have been the Zinfandel and Thompson seedless (I have for eating- definitely not trying to make wine with those). The Merlot and Cabernet Sauvignon have not had this leaf burning, so I assumed it's just something Zinfandel are prone to. In the first picture that shows the whole vine you can see there are several stunted shoots, only the middle and ends of the vines actually grew and produced any fruit. In the last pic you can see the sharp shooter I saw earlier this month, but I couldn't get a closer shot.

 

[vtoddw]

Correction, I was indeed taking pictures in 2020, here's the Zinfandel vine that was dead by spring of 2021 which I mentioned in the last post. I figured that it was because I got greedy and over cropped it, which I assumed is why I ended up with all that uneven berry ripening you see in the picture here. I have a new vine in it's place this year which is doing well, so assuming this was killed by Nematodes I'm guessing they may kill this one by next year too unless I can turn it around with Movento.