Rhizoshpaera treatment

[ATH]

Has anybody played around with options enough to feel that you can say one product is definitively better than others?

Spruce trees came out a couple of weeks ago up here, so I've done round 1 - looking. I have been using Chlorothalonil, but that label switched from signal word "Caution" to "Warning". I try to avoid that if possible...both for applicator health, but when a client asks "how toxic is the spray you are using" I like to explain the 3 signal words found on products and that the one I am using is the "lowest" of those 3... Can't do that with Chlorothalonil any longer. I also like to switch fungicides to avoid building a resistant population.

I do see some recommendations on some Extension factsheets for Thiophanate-methyl (Cleary's 2226). That still has a "caution label" (but when you put the 2 together, you get a "Warning" signal word...).

Open to other suggestions. (didn't get much action on the Buzz, so we'll see if it does here...)

Thanks!

 

[Jed1124]

Chlorithalonil is what I've been using as well. Nasty stuff. My techs hate it too. I've used Junction but now we're up to a danger. I'd like to switch to something less toxic myself.
I have been using Cambistat in conjuction with spraying with success. It thickens the cuticle on the needles making them more resistant to fungal infection. Also helps slow the progression of cytospora canker.

 

[Jason Douglas]

A phosphite may help as well. Systemec induced or aquired resistance.

Blue spruces are junk for our area, get rid of them before Norways get stressed and infected. I may have mentioned something along these lines before...

 

[ATH]

I agree...but the designers apparently love them. They form nice privacy barriers, then they start to die.

Norway certainly does much, much, much better. I've been trying some Serbian spruce as well. There aren't many around, so it is hard to get a good feel for those...have you had any luck or know of big ones around you that are either doing well or not?

I've wondered if Reliant would do any good. That would probably be my preferred fungicide if it would work. I understand that copper-based will work for Rhizosphaera too, but won't last past the first rain... I keep reading and asking and think I have ruled out Thiophanate-methyl. Round 2 will probably be back to Chlorothalonil, but I still want a better option.

 

[ATH]

So here is a slightly crazy twist. I ordered another jug of Chlorothalonil from Midwest Arborist Supplies. They switch brands between QualiPro and Omni - I've talked to them about that, and they are just chasing the lowest price from the wholesaler. Normally no difference.

Had QualiPro before. It is 54% Chlorothalonil and has the WARNING label.

Got Omni this time. It is 53.27% Chlorothalonil and has a CAUTION label.

Think that 0.73% was enough to "cheat" the system and get it down to a Caution? I'm still wanting other options for Rhizosphaera...but for now, at least I am back to a caution label.

links:
Omni label

QualiPro label

 

[ATH]

PS: Both say they contain 6 lbs of AI per gallon (or 720 grams per liter). Must be a rounding thing. I'm betting that is the real reason Omni has a lower %...they are pinching a few pennies.

 

[Jed1124]

Formulation can be the difference between a caution and a warning. Adjuvants or stickers in the blend can make the difference not just the active ingredient.

 

[Jason Douglas]

Yeah the carrier agents can oftentimes make the difference. Like how orchard products can have the same active ingredients as a T&O but the T&O can be used in orchards.

I was thinking using a phosphite as a supplemental treatment rather than exclusively. Any of the Strobi class have Rhizo labeling?

I don't see many old Serbians if that helps. Beautiful trees though.

 

[Dbodave]

This is an old thread but I haven't used chlorothalonil in years for multiple red flags, probably the main one being the restriction not to use in a residential setting.

The 2 products I primarily use for rhizo are thiophanate methyl and tourney. Both are systemic and last much longer than chlorothalonil which is a contact and only lasts 1 week. If you stagger these products you shouldn't run into the problem of resistance since use different modes of action.

I prefer products with systemic modes of action since they can provide up to 4 weeks control vs. Chlorothalonil which is a contact and only good for 7 days. I do carry a jug of junction mancozeb if I need a contact but I very seldom need it. The exception is diplodia, but we are pretty happy if we get a reduction in shoot blight by 90%.

Taking things further our main diseases we spray for are apple scab, rhizo and diplodia/dothistroma. I stagger my products between each round of sprays to reduce the likely hood of resistance and have the schedule planned that if I'm still in round 2 of apple scab but need to start rhizo 1, the same product I'm spraying will work for both trees if needed.

Staggering modes of action between each spray has greatly reduced application failures and customer call backs.

 

[ATH]

You've had good results with Tourney and 3336?

I also heard a recommendation for Humates and Fulvic acid as they supposedly "displace" the fungus on the 'recepors' where it would normally attach to the plant. Another arborist told me they mixed Root Magic in with their fungicide as a foliar fertilizer and had great results. That is a humic acid product with fulvic acid. I'm wondering if that worked so well because of the reason stated above???

Thanks!

 

[Jed1124]

This is an old thread but I haven't used chlorothalonil in years for multiple red flags, probably the main one being the restriction not to use in a residential setting.

The 2 products I primarily use for rhizo are thiophanate methyl and tourney. Both are systemic and last much longer than chlorothalonil which is a contact and only lasts 1 week. If you stagger these products you shouldn't run into the problem of resistance since use different modes of action.

I prefer products with systemic modes of action since they can provide up to 4 weeks control vs. Chlorothalonil which is a contact and only good for 7 days. I do carry a jug of junction mancozeb if I need a contact but I very seldom need it. The exception is diplodia, but we are pretty happy if we get a reduction in shoot blight by 90%.

Taking things further our main diseases we spray for are apple scab, rhizo and diplodia/dothistroma. I stagger my products between each round of sprays to reduce the likely hood of resistance and have the schedule planned that if I'm still in round 2 of apple scab but need to start rhizo 1, the same product I'm spraying will work for both trees if needed.

Staggering modes of action between each spray has greatly reduced application failures and customer call backs.

Is the thiophanate methyl and tourney labeled for needs cast? Ct is a real stickler about the actual disease being on the label. I know, I’m being lazy, I can just look myself, but it’s late

 

[ATH]

I knew 3336 was. I looked up Tourney and it specifically has Rhizosphaera on the (supplemental) label.

 

[Dbodave]

It works, we spray 3336 for the first spray and tourney for the second. Switching from a group 1 fungicide on the first spray to a group 3 fungicide on the second spray helps prevent the disease developing resistance. Tourney is kind of costly but goes a long way and is very versatile.

We did try using junction one year for our needle cast which is mancozeb and copper sulfate. It's a contact that works on multiple modes of action like chlorothalonil, but I didn't like using it too much. Kind of thick and green. It's very versatile though and labelled for practically everything. I do keep a jug on hand if I need a contact for other diseases that develop quicker, like scab and diplodia.

 

[ATH]

Thanks! I think I'll switch it up next year. Product cost is a relatively small portion of the total treatment cost picture, so won't make a big impact on the bottom line.