Stunted shoot

[tjpfeister]

It was raining after work today, but I jogged up to the field to see how the plants were doing- all 66 are throwing up shoots. Going into season three, I'm on the look out for oddities and I stumbled across this isolated instance on a chinook. One shoot stunted shoot with short nodes and a lighter, yellow discoloration. I didn't flip leaves over or anything, I'll inspect closer tomorrow, but if memory serves, is this potentially downy mildew? Localized to just one shoot though?

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[PapaBearJay]

Downy.

 

[Senormac]

that's weird....but cool. I'd let it grow and watch it to see what happens

 

[Ruint]

I don't know that downy would discolor the shoot like that TJ...could be a possibility. Have you crowned them? That usually is the best way to ensure that you are not promoting the growth of downy mildew. New buds are formed in the fall, and overwinter right on the crown...downy likes to overwinter right there with them, so when it's time for the shoots to get going, the fungus is right there to get a jump on growing too! At 3 years old, you have no worries about damaging your plants by doing a crowning. To play on the safe side, you can clip that 1 bine off and remove it from your growing area. As I am sure you know, you'll have more than enough opportunities to replace that 1 bine by more shoots coming....

 

[PapaBearJay]

That is a downy spike. Feel free to toss it in a sandwich bag with a damp paper towel. If it hasn't sporulated already then you will see fuzzy gray/purple/black masses the following day. Make sure you leave the bag in a dark, cool spot to induce sporulation.

You do not want downy mildew in your yard as a commercial grower, it will be the bane of your existence.

@tjpfeister Yes, although all commercial varieties are susceptible to downy mildew, some are more tolerant than others. This is also your second year, correct? The disease hasn't spread a great deal in the yard, which means you can nip it early. Speak with your local extension agent about getting on an effective spray program.

 

[Sbe2]

Any advice to homegrowers on how to treat downy?


Trimming, fungcides, anyone have any luck with either method?

 

[PapaBearJay]

Trimming is your best option. Many fungicides labeled for use to control downy cannot be used on the home scale.

 

[tjpfeister]

Third year for most of the plants, fourth year for 11 of the 66. Interestingly (and frustratingly) there is a high occurance of downy showing in my chinook plants, some in my cascade, and zero in my centennial plants. (We just trained and pruned today). So now I need to explore my fungicide options it seems... Papabearjay doesn't have me feeling too optimistic

 

[Ruint]

Look for Rampart fungicide...it kills downy mildew....Cueva is another product that helps prevent downy...getting either of those in a small "home-scale" container might be the challenge. I buy mine in 2.5 gallon containers which would last you years and years...

 

[PapaBearJay]

Look for Rampart fungicide...it kills downy mildew....Cueva is another product that helps prevent downy...getting either of those in a small "home-scale" container might be the challenge. I buy mine in 2.5 gallon containers which would last you years and years...

These are agricultural chemicals. These specific fungicides may not be used on the "home-scale". There are, however, fungicides that are labeled for use in a residential setting which can be purchased at your local garden store. Having said that, he has 66 plants, which is quite a bit more than a "home-scale" operation so it may be to his benefit to obtain his pesticide applicator license and begin making fungicide applications on a "commercial-scale".

 

[tjpfeister]

I have been meaning to make it over to my local extension office and take whatever exams I need to take. The problem is that I have two infants and four children total that make it tricky to find time for anything. Excuses aside, I picked up some stuff from my local farm and fleet store. It might not be my best option, but this is 30% concentrate chlorothalonil, which is supposedly effective against downy

 

[B-Hoppy]

Probably might not be the best LEGAL option.

"Below, I have outlined a general foliar fungicide program by calendar for Wisconsin hop yards with additional notes in the right -*‐ hand column. If you raise other crops and have familiarity with common base protectant fungicides, remember that you cannot use captan, chlorothalonil, or mancozeb on hops. "

From this document: http://ipcm.wisc.edu/download/misc/...-control-in-Wisconsin-hop-production-2016.pdf

 

[tjpfeister]

Argh.

 

[tjpfeister]

Ok, so I chickened out and did not use the chlorothalonil. Though, I find myself wondering why it's great for zucchini, but not for hops. Im guessing that it has to do with lack of studies and how long you have to wait before safely harvesting after application.
The weather has finally dried up, so Im behind as usual, but Im going to get out there and hammer them with copper octanoate- which, thankfully, DOES list hops on label.
Im wondering how Im going to effectively apply it to the undersides of the leaves though, as I only have a backpack sprayer at my disposal. "Very carefully" is likely the answer.
Plus, as I understand it, I want to find a second (non-copper based) product to alternate. *sigh* some hobby, eh?

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[B-Hoppy]

Ok, so I chickened out and did not use the chlorothalonil. Though, I find myself wondering why it's great for zucchini, but not for hops. . . .

The organisms that caused downy on hops and zucchini are different and most likely require different fungicides for their control. I guess there's a reason some folks actually go to school to learn about things other than computers, haha! https://www.ncbi.nlm.nih.gov/pubmed/21405990

 

[tjpfeister]

Howabout that? A dumb mechanic like me just assumed downy mildew was downy mildew. Thanks B!