Browning on hop leaves

[archthered]

All of my hop plants have leaves that are turning brown. Most of it seems to be in spots though there are a few that also seem to have browning at the edges. There is some yellowing though the lighting in some of the pictures makes the brown look more yellow that it is in real life. There is also a couple, literally like two, leaves that clearly have been eaten by bugs. I have not been too worried about that since it is not much damage but I don't know if maybe I should do something about it now.

I have Sevin spray and Super Eight for bug killer but since one of my plants has started to put out cones I hesitate to use those especially if the browning is not pest related. I think it's fungus but I'm not sure I do have a general fungicide, Fung-onil with Chlorothalonil as an active ingredient, for gardens but again with cones coming in I'm not sure that's a good idea though it says most veggies can be harvested within a week or two after application so it may be ok. I also have general fertilizer if that is the issue.

The plants are of varied varieties and are all 2 or 3 years old. I'm not certain they all have the exact same thing but I do strongly think so. I'm adding pictures to help. I thought this may have started about a week ago but it was too light to be sure it wasn't just paranoia. I went out of town and after I got back it was obviously a problem. Other than this they are pretty healthy plants, they are all like 20 feet tall and I was looking forward to a great harvest since bugs and whatnot hadn't been bad this year.

Any advice is greatly appreciated.

 

[Bubbles2]

Couple things it may be. Hops and MJ are about the same, well most plants. So those spots look like a Nutrient Lock out. For instance if there is a cement slab under that shed, that will have an effect on your PH, if PH of soil is wrong either way, things like Calcium ( the plants and humans defense mechanism) it will bud rot later. Also that browning could be Nute burn, where you are feeding it good, or how you are watering. EG., going over and adding a gallon or two of H20 instead of water soak, let dry to 1.5" at soil top and then resoak as needed. I cannot stress enough the value of a Book when growing a certain exotic, a Ph Meter, and Compost Tea for consumable plants. All these forums can get you close, but a book, a meter and comparison photos are no match for guessing, which is what I did with my "couple of things."

 

[archthered]

I have an all-in-one pH,nutrient, and a bunch of other things meter that I use for the garden. I used it on one of the plants not long before I started seeing this browning. It said the pH was around 6, which my understanding is ok for them, additionally it said the nutrient level was a little on the high side but not much. As for the water I water in the morning most mornings, depending on recent rain, hot them pretty hard with the water and then water other nearby plants and then come back to the hops for another light sprinkle.

 

[Soulshine2]

The 4 of mine get slow drip all day. 55 gallon barrel on its side in a cradle, crack a valve going to a hose/pvc manifold to the base of the plants buried under mulch. They couldnt be happier.

 

[Bubbles2]

I have an all-in-one pH,nutrient, and a bunch of other things meter that I use for the garden. I used it on one of the plants not long before I started seeing this browning. It said the pH was around 6, which my understanding is ok for them, additionally it said the nutrient level was a little on the high side but not much. As for the water I water in the morning most mornings, depending on recent rain, hot them pretty hard with the water and then water other nearby plants and then come back to the hops for another light sprinkle.

Well try backing off the Nute's and see if she clears up. I'd get a book, even if it was from the library or used on the Net. Books Rock!

My Grapes get like that when the watering gets funky, it rains like 3" in two days here and then nothing for a week or two at times. My Concords, my Muscadines are like weeds, adapt to all.

 

[Northern_Brewer]

All of my hop plants have leaves that are turning brown. Most of it seems to be in spots though there are a few that also seem to have browning at the edges. There is some yellowing though the lighting in some of the pictures makes the brown look more yellow that it is in real life. There is also a couple, literally like two, leaves that clearly have been eaten by bugs.

You don't say what continent you are on, let alone your location - this would make a difference.

But the skeletonisation that is most obvious on pic 2 looks like beetle damage (chafers, weevils etc). Examine them carefully to see if you can find any of the culprits. The response depends a bit on what beetle it is, which in turn depends in part on where in the world you are; but finding them is the best way to ID them.

Whilst the spotting in the other pictures could be fungal, my immediate guess is that it is sap-feeders of some kind. Look really carefully at the undersides of the leaves, can you see any (possibly minuscule) flecks that shouldn't be there? Any signs of webbing (like spider web but finer and denser)?

A lot of plant pathology comes down to just looking really carefully at your plants, particularly in the bits that predator can't see like the undersides of leaves and in the nooks and crannies of the stems etc.

 

[archthered]

You don't say what continent you are on, let alone your location - this would make a difference.

Sorry, I meant to include that but forgot, I'm in NW Missouri USA

But the skeletonisation that is most obvious on pic 2 looks like beetle damage (chafers, weevils etc). Examine them carefully to see if you can find any of the culprits. The response depends a bit on what beetle it is, which in turn depends in part on where in the world you are; but finding them is the best way to ID them.

In the days since I initially posted this there has been little to no additional damage of this nature. I have not seen any potential pests that would do this kind of damage. I do not expect no bug damage but rather just try to limit it so the fact that it hasn't gotten worse is good enough on that one, for the moment. I was more interested in peoples opinion of applying Sevin while one of the plants is beginning to form cones.

Whilst the spotting in the other pictures could be fungal, my immediate guess is that it is sap-feeders of some kind. Look really carefully at the undersides of the leaves, can you see any (possibly minuscule) flecks that shouldn't be there? Any signs of webbing (like spider web but finer and denser)?

I typically, but admittedly not always, look at my plants pretty well when I water. Initially I did not find any evidence of webs or anything like that. Earlier today, I've not been out as much lately due to life, I noticed increased browning on most, but not all plants, and I did find some web like structures. The plant with the cones had no webs but are also the one with the least issues. The others had increased browning and I did find some evidence of webs and a couple potential flecks. It's hard to say for sure if it is really from insects or how bad it is since the cottonwood trees have been kicking out their fluff and some of the fluff is definitively from them since I can see the seed within the fluff. That said I do think some are NOT from the cottonwoods. If it is some kind of sap feeder will Sevin or Super Eight, I can look up the active ingredients, be ok to use? If not what can I do? Should I hit it with both the bug killer and the anti-fungal I have?

On a related note I have been thinking more about the watering and backing it off as well as being more mindful of how I water, this does not seem to have helped.

Thanks to everyone for all the help so far

 

[Leezer]

You could try neem oil. I’ve had leaf hoppers on my hop leaves and used neem oil to get rid of them. It can take several applications, but I like it because it’s not chemicals.

 

[Bubbles2]

You could try neem oil. I’ve had leaf hoppers on my hop leaves and used neem oil to get rid of them. It can take several applications, but I like it because it’s not chemicals.

Captain Jacks too if you are an organic Gardner

 

[Northern_Brewer]

I have Sevin spray and Super Eight for bug killer but since one of my plants has started to put out cones I hesitate to use those especially if the browning is not pest related. I think it's fungus but I'm not sure I do have a general fungicide, Fung-onil with Chlorothalonil as an active ingredient

Wow - I've just looked them up, Sevin contains carbaryl, Super Eight is permethrin, both of which have been banned (or nearly so) in the EU for over a decade. However they're rather different - carbaryl is banned mainly because it is so toxic to mammals (so you don't want it going on food) whereas permethrin is more persistent and toxic to aquatic ecosystems/fish but isn't much of a worry for human consumption.

Aside from the toxicity angle, the problem with these kinds of broad-spectrum agents is that they kill off the much more fragile population of predators, so can actually make the infestation worse.

Chlorothalonil has also just been banned by the EU, but has been used for many decades as one of the main fungicides on wheat and by the standards of these things is reasonably benign. However, the main fungal diseases to worry about on hops are downy mildew (if damp), powdery mildew (if dry) and Verticilium wilt (fairly rare and not really a problem in the US). The mildews are pretty easy to recognise.

I noticed increased browning on most, but not all plants, and I did find some web like structures. The plant with the cones had no webs but are also the one with the least issues. The others had increased browning and I did find some evidence of webs and a couple potential flecks.

The presence of webs rather confirms my initial suspicion that you've got spider mites. The first half of this presentation has some useful background and pictures (before then going into technicalities about mechanisms of pesticide resistance) also see this article. In general if you've got spider mites then you're better off using a specific acaricide ("mite-killer"), but even then you will kill predatory mites - this is one case where biocontrol by adding more predators actually works pretty well. I hesitate to recommend a specific course of action since I don't know your climate and pesticide market, but if it is spider mite then that at least gives you something to ask local experts about.

 

[archthered]

I have a question and a plan!

Question- Will the leaves already affected by the spider mites recover once they are gone?

Plan- Use Neem oil every 7 days for 2 or 3 weeks. Then, if I can get them, add predatory mites, hopefully this will salvage my harvest this year. After harvest remove all mulch and cover and burn it, then apply Neem oil to the ground covering the plants and burn the rope the hops are climbing, I usually try to get 2 years out of a piece of rope and this is only year 1. Cover plants after the first frost or two but before the real cold sets in. In the Spring remove mulch/cover and spray Neem oil again when the mites are likely to be re-emerging from their winter hidey holes, add new cover and then add predatory mites. If I can get small quantities add predatory mites once or twice during the growing season. The following year add predatory mites in the Spring again and keep a better eye out for early signs of spider mites from here on out and add predatory mites when it looks like they are coming back which will hopefully be rare as this will maybe bring some kind of balance back.

Some of my thinking- I need to eliminate the mites in this year and in the future, just using predatory mites will take too long, especially since I'm not sure how soon I can get them, so I need chemicals/Neem oil this year. The mites will try to over-winter in the soil so burn everything that was in contact with them this year. Neem oil is supposed to help limit future outbreaks if applied to the soil, frost and cold also kill spider mites so exposing the plants to the cold for a bit is good as long as I don't over do it and injure the plants, which should not be too big of a concern since hops do well in cold. One final Neem oil application should kill anything that makes it through the winter and then adding predatory mites should limit the need for further action and let nature handle it, though I want the balance to be on the side of the predators even if this means many go hungry and die the first few applications.

I hope to update this with progress so if it works others can try this if they have the same problem and so they can try something else if it doesn't work.

 

[Ruint]

Sulfur powder used in a duster, or billows type applicator works very well on mites. Just don't over apply as you will sulfur burn your leaves.