Author Topic: Deformed Hop Plant  (Read 2280 times)

Offline b-hoppy

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Re: Deformed Hop Plant
« Reply #15 on: May 26, 2011, 09:01:24 PM »
Herbicide damage was my first thought as the chemical can reach non-target plants not only by volatilization but also by drift.  Windy conditions or high pressure at the nozzle can create problems.  Cupping of the leaves is one sign and another would be the stunted growth.  It does not look like downy mildew as the lower leaves are usually the first to show signs of the disease.

I've had some leaf cupping occur during years of intense rainfall but couldn't really pinpoint the excess moisture as the sure cause. 

Now that the damage is done about all you can do is wait.  I have a feeling the little girl will make a come-back as their kind have a strong will to live.

Offline gmac

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Re: Deformed Hop Plant
« Reply #16 on: May 26, 2011, 09:25:06 PM »
I'm not sold on herbicide damage although it's possible.  Rapid growth from 2,4-D or dicamba (both part of standard lawn spray) overspray causes epinastic growth which results in twisting and cupping.  These herbicides are IAA mimics (indolacetic acid) which duplicate plant hormones responsible for cell elongation which is what leads to the distortion.  Thing is, if it was a very low rate of drift I would expect more cupping of the leaves and leaf elongation.  At higher rates, the leaves become small and stunted but the stem becomes dramatically twisted.

My thoughts are that virus is the most likely.  Some of the "mosaic" viruses can cause similar growth although it is often accompanied by light and dark patterning of the leaves (in a mosaic pattern, hence the name).  Aphids were also mentioned and many viruses are vectored by aphids or other sucking pests.  Can't say for sure that this is the case but that's my guess based on the pictures. 

Just to back this up, I spent over 10 years doing formulation chemistry screening for a major agriculture herbicide company and I am a certified crop advisor and agronomist so I'm not completely guessing.  I'd say either a virus or herbicide drift.  Not sure that it came in the mulch, kind of unlikely because most of the herbicides used today have very little carry-over but it's possible I guess.

If it's herbicide damage, it should grow out of it next year.  If it's a virus, they'll likely die.  Sorry.

Offline brewmichigan

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Re: Deformed Hop Plant
« Reply #17 on: May 27, 2011, 09:19:44 AM »
I'm not sold on herbicide damage although it's possible.  Rapid growth from 2,4-D or dicamba (both part of standard lawn spray) overspray causes epinastic growth which results in twisting and cupping.  These herbicides are IAA mimics (indolacetic acid) which duplicate plant hormones responsible for cell elongation which is what leads to the distortion.  Thing is, if it was a very low rate of drift I would expect more cupping of the leaves and leaf elongation.  At higher rates, the leaves become small and stunted but the stem becomes dramatically twisted.

gmac, I don't have any other pics right now but almost all the leaves on the plant are cupped. That was the first sign of damage. I thought they might have had either too much or too little water. I know it's not too little so I thought they were over watered but the herbicide theory fits much better.

I like the response though. Very thorough.
Mike --- Flint, Michigan

Offline gmac

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Re: Deformed Hop Plant
« Reply #18 on: May 27, 2011, 09:32:38 AM »
If the leaves are more cupped, I'd go with low rate of herbicide drift injury.  Lawn sprays are almost all comprised of phenoxy herbicides like I mentioned above which causes that symptom.  I'm not that far from you (I'm in Ontario) and so I know we've both had a heck of a wet spring but I don't think that would cause it although I'm not as familiar with hops as with row crops.

It could grow out of it depending on the rate.  I've done titration trials down into the ppb range and these sorts of products are very active, even at ultra-low rates.  If it grows out of the damage and bears cones, I would use them but not everyone would.  Thing is, if the plant recovers then the herbicide has been metabolized or degraded sufficiently for the plant to over come it which means that any residue in the cones would be at an incredibly low rate but if you have concerns about using the cones, that's your choice.  If the plants survive and I think they likely will as long as the growing point is not killed (still growing even though distorted), they should be fine next year.

You could remove the mulch and replace it on the off-chance that it was a carry-over problem with the mulch but I don't think that's as likely.  More likely is drift from a neighbour or yourself applying lawn chemicals.  Some of them exhibit a phenomenon called vapour drift where the product will volatilize and move off-target even if there was absolutely no wind (dicamba is particularly notorious for this).  I burnt my hydrangea last year and I think I know what I'm doing.  It happens a lot when temps get really high.   

Offline brewmichigan

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Re: Deformed Hop Plant
« Reply #19 on: May 27, 2011, 10:44:13 AM »
Well 2,4-d was used so if dicamba is known for drift, I would think that is the issue. I think the plant is done for the year though. All the ends are so deformed it's not growing like it should which isn't a problem. It will be back next year and hopefully that should be a good year since it'll 4 years by then. Thanks the awesome replies.
Mike --- Flint, Michigan

Offline hopfenundmalz

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Re: Deformed Hop Plant
« Reply #20 on: July 12, 2011, 05:03:59 AM »
My plants that look bad in the spring are doing well now, but were delayed a bit by the deformed growth.  Must have been the overspray as gmac suggested.

Might even get some off of the chimook.
Jeff Rankert
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Offline brewmichigan

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Re: Deformed Hop Plant
« Reply #21 on: July 12, 2011, 06:50:56 AM »
Mine are the same. Because the spraying happened so soon in the spring they shot right through that and are big and bushy now. They're so out of control they broke the stake I have them attached to.
Mike --- Flint, Michigan

Offline Slowbrew

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Re: Deformed Hop Plant
« Reply #22 on: July 12, 2011, 07:05:05 AM »
I'm sure everyone know this but avoid windy days when spraying any herbicides.  Even if they aren't prone to drift the wind will drive them all over.

Some of the lawn service companies in Des Moines spray lawns whenever it fits their schedule, rain or shine or gale force winds.  Makes me shake my head.

Glad to hear the plants survived.  I hope next year is better.

Paul
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