Fungicide prophylactic useage

[WNC Bonsai]

Fungicide use seems to be a recurring issue with bonsai, but when you go to a manufacturers website for information it is often confusing especially when it comes to bonsai—most talk about spraying at rates to cover acres not pots. Here in Western North Carolina it can get pretty humid in th summers and things like leaf spots and rusts are very common. Recent information from the state ag folks suggests that the occurrence of cedar apple and similar rusts are on the increase.

I have seen Clearys 3336 suggested but can folks with experience talk a little about the application of this and other fungicides to be used and just which diseases they work with. In my case I have pine, juniper, quince, hawthorne, japanese maples, trident maples, and elms in my collection. I know too that there is cedar apple rust, powdery mildew, downy mildew, leaf spot of various kinds, and probably pine blight in my neighborhood in addition to what I don’t know about. I have tried peroxide treatments and found them ineffective so need something a bit stronger. Consequently I am searching for the best combination of fungicides to use on a regular prophylactic schedule on a rotational basis to avoid buidling up resistance.

 

[WNC Bonsai]

Just to get the discussion going, I plan on using Daconil and Clearys starting at leafout next spring and alternating their application per the timing suggested on the labels. So does anyone else follow this or a similar schedule? Are there any warnings others might share based on their personal experiences with these or other chemicals? Do the label application rates and timings work for a broad spectrum of plants used for bonsai? Will they kill any?

 

[Adair M]

About the Cleary’s:

It’s designed to be a fungicide for lawns. It “just so happens” to be effective against needle cast in pines kept in bonsai pots. No scientific test have been done, to my knowledge.

I will share my experience: since it’s designed for lawns, it’s sold in huge bags, and is applied with a spreader. I don’t need that much.

I found a substitute sold on smaller quantum’s, with the same active ingredient as the Cleary’s: Bonide Infuse Systemic Granular Fungicide. You can get it on Amazon.

Needle cast infects the needles as they develop. It doesn’t show up until months later. So, apply the fungicide to the soil before the candles begin to make needles. So, I apply some as the candles are growing I. The spring. And again about two weeks after I have decandled in the summer.

For small trees, I apply about a teaspoon. Later trees get about a tablespoon.

I use it on all my pines, and Atlas Cedar.

 

[KLSbonsai]

Cofga, Daconil and Cleary's are the same active ingredient. Chlorthionil is the active. It is long since out of patent rights and there are lots of generics. There is a good website for both insecticides and fungicides called "do your own pest control". I am a director of horticultural services for a landscape company and work with many of these products on a daily basis. As a good rule of thumb on hot summer days apply any pesticide early in the morning or late in the evening.

 

[Paulpash]

This could be useful to you, thanks to @markyscott

https://www.bonsainut.com/resources/dormant-season-spraying.36/

 

[WNC Bonsai]

Cofga, Daconil and Cleary's are the same active ingredient. Chlorthionil is the active. It is long since out of patent rights and there are lots of generics. There is a good website for both insecticides and fungicides called "do your own pest control". I am a director of horticultural services for a landscape company and work with many of these products on a daily basis. As a good rule of thumb on hot summer days apply any pesticide early in the morning or late in the evening.

According to the label Clearys 3336 is not Chlorthionil, its active ingredient is Thiophanate-methyl. Daconil however is Chlorthionil.

 

[KLSbonsai]

Sorry your right. I buy products from a supply that has all private label products. Both of those we lost for the turf care market in the past five years buy can still use them for trees and shrubs. The government's philosophy you cant spray it below your feet but you spray it above your head. I mostly use a fungicide called SysStar it is a combination of two systemic fungicides that can move from the roots up to the leaves or from the foliage to the roots. It's a combo of Eagle from BASF and Systec from Regal Chemical. Covers a really wide range of diseases.

 

[WNC Bonsai]

We have a local company here, Southern Ag, that makes their own versions of each. I think I’ll buy local and see how these work. We had leaf spot run rampant here last summer and I know I have at least one amelanchier and a couple hawthorns with CA rust in my yard. So I need to get ahead of this stuff next spring. So far my juniper has not come down with it but my,luck isn’t likely to hold.

 

[KiwiPlantGuy]

Hi Cofga,
So after 20 odd years in Horticulture I have come across plenty of fungicides. Many of these are available in my country and yours under different brands but same active ingredient.
So to make this post as easy as possible to understand I thought I would describe as below. (Sorry if this info is already known and understood)
1. PROTECTANT - Sprayed to run off plus sticker/spreader achieves the job of protecting the leaves from invasions of certain fungi. Each (active ingredient) chemical has a different range of fungi to help protect. You have to research what fungi you are trying to protect from. Also the large majority (not all) have no eradication properties.
Eradictant- These fungicides work to kill the infestation (fungal disease) present. BUT if you continuously use the same eradicant fungicide you will probably get a resistance (eg. It won’t kill off target fungi). So you have to change fungicide family groups to try and
stay ahead of the fungi and any resistance.
So therefore you can use a combination of the 2 plus fungicides for control/protection of most of your problems each year. And change family groupings fortnightly will work well in the long run.

So in summary you have to read the label of the chemical in question to see which fungi it protects or controls and researching which fungi you need help with.
With your given example, Thiophenate-Methyl is an eradicant with minimal protectant properties, but I can’t remember whether it controls rust - my guess is not. Also switching between Mancozeb (known protectant for rust) and Diconal may work but I think they are both in the same group. Eradicant for rust I would use is either Tilt (ec) or Alto but these maybe only commercially available.
I can’t stress enough that a Sticker/Spreader is a HUGE must (stays attached for up to 2 weeks) and is a chemical one not dishwasher liquid as is water soluable. Also don’t be tempted to mix fungicides with Lime Sulphur as not compatible.
Now, if that is too much theory, I am happy to elaborate more.
Charles

 

[WNC Bonsai]

Hi Cofga,
So after 20 odd years in Horticulture I have come across plenty of fungicides. Many of these are available in my country and yours under different brands but same active ingredient.
So to make this post as easy as possible to understand I thought I would describe as below. (Sorry if this info is already known and understood)
1. PROTECTANT - Sprayed to run off plus sticker/spreader achieves the job of protecting the leaves from invasions of certain fungi. Each (active ingredient) chemical has a different range of fungi to help protect. You have to research what fungi you are trying to protect from. Also the large majority (not all) have no eradication properties.
Eradictant- These fungicides work to kill the infestation (fungal disease) present. BUT if you continuously use the same eradicant fungicide you will probably get a resistance (eg. It won’t kill off target fungi). So you have to change fungicide family groups to try and
stay ahead of the fungi and any resistance.
So therefore you can use a combination of the 2 plus fungicides for control/protection of most of your problems each year. And change family groupings fortnightly will work well in the long run.

So in summary you have to read the label of the chemical in question to see which fungi it protects or controls and researching which fungi you need help with.
With your given example, Thiophenate-Methyl is an eradicant with minimal protectant properties, but I can’t remember whether it controls rust - my guess is not. Also switching between Mancozeb (known protectant for rust) and Diconal may work but I think they are both in the same group. Eradicant for rust I would use is either Tilt (ec) or Alto but these maybe only commercially available.
I can’t stress enough that a Sticker/Spreader is a HUGE must (stays attached for up to 2 weeks) and is a chemical one not dishwasher liquid as is water soluable. Also don’t be tempted to mix fungicides with Lime Sulphur as not compatible.
Now, if that is too much theory, I am happy to elaborate more.
Charles

The really important thing is finding the right combination to do the job and not end up with resistance. A lot of the labels don’t provide a full description of which diseases they protect against, just a generic term like rusts or leaf spots, etc. Daconil seems to be a favorite of many and I see Mancozeb mentioned often along with Cleary’s and sulfur. And of course so much of the online info is focused on either the fruit and vegetable growers or turf production. I was kind of hoping some of our more experienced members might offer their experiences with these combinations of chemcial and diseases.

 

[bwaynef]

With your given example, Thiophenate-Methyl is an eradicant with minimal protectant properties, but I can’t remember whether it controls rust - my guess is not.

Thiomyl:
Gymnosporangium (Rust)
Puccinia (Rust)
Uromyces (Rust)

 

[ysrgrathe]

This is a really excellent resource for determining what fungicide to use, because it lists methods of action and whether or not rotation is needed.
http://ipm.ifas.ufl.edu/resources/success_stories/T&PGuide/pdfs/Appendices/Appendix6-FRAC.pdf

Some notes from labels. Please verify against your own labels as there is sometimes confusion about brand names / concentrations / locality-specific regulations.

 

[Leo in N E Illinois]

In general, it is best to not spray ''prophylactically'' because whether you believe it or not, the cumulative run off from urban and suburban garden & lawn chemical use is a serious issue. Also there is the issue of developing a local resistant strain of various fungi. Fungi develop resistance much more rapidly than insects do.

However, because the OP, @Cofga knows there is a local, resident issue with rust disease, his program is appropriate. The whole topic of fungicide use is complex, and there is little or no ''data'' specifically bonsai. An excellent resource, is your local Ag Extension Agent. In the USA all land grant universities have a department devoted to Agriculture Extension Services. There is a lot of free on line information available for training for the Pesticide Applicator's License. This will include fungicides, and most important safety. It will also list chemicals approved on a state by state basis, and for which crops. It may be worth purchasing the manual for Tree and Nursery Crops. The cost of the manuals is modest, if you have trees worth more than a couple hundred, you really should look into these books. The whole concept of integrated pest management is explained fairly well in these books, much better than one could ever glean from postings here on BNut.

Interestingly the choice of Daconil and Cleary's 3336 is good, as both are in different mode of action groups, and the Daconil is a mode of action that is difficult to develop a resistance to. So the above program overall is pretty good.

 

[WNC Bonsai]

I agree that spraying for the sake of spraying is not good and leads to develoment of more resistant strains. However, as @Leo in N E Illinois pointed out I know there is rust in my yard and every summer by August many of my Japanese maples have a nice coat of mildew on them and last summer my slippery elm had a good case of leaf spot. For these reasons a preventative spraying program seems a reasonable prventative measure for those specific diseases. The table posted by @ysrgrathe is great to see, just the kind of go to resource I was looking for—thanks. Is this table available as a spreadsheet?

 

[ysrgrathe]

Sure, let me know if the published version of the spreadsheet works:

https://docs.google.com/spreadsheet...JteOB4uF8y/pubhtml?gid=1434384811&single=true

 

[WNC Bonsai]

Sure, let me know if the published version of the spreadsheet works:

https://docs.google.com/spreadsheet...JteOB4uF8y/pubhtml?gid=1434384811&single=true

I can read it but can’t find any way to save it offline, any ideas?

 

[quietobserver]

About the Cleary’s:

It’s designed to be a fungicide for lawns. It “just so happens” to be effective against needle cast in pines kept in bonsai pots. No scientific test have been done, to my knowledge.

I will share my experience: since it’s designed for lawns, it’s sold in huge bags, and is applied with a spreader. I don’t need that much.

I found a substitute sold on smaller quantum’s, with the same active ingredient as the Cleary’s: Bonide Infuse Systemic Granular Fungicide. You can get it on Amazon.

Needle cast infects the needles as they develop. It doesn’t show up until months later. So, apply the fungicide to the soil before the candles begin to make needles. So, I apply some as the candles are growing I. The spring. And again about two weeks after I have decandled in the summer.

For small trees, I apply about a teaspoon. Later trees get about a tablespoon.

I use it on all my pines, and Atlas Cedar.

I tried a Cleary’s this year in my satsuki’s & Quinces after reading you and a couple other people suggesting it. I’ve had some nasty fungal issues for a few years on several of them. New leaves are all fungus free all year, so at least in my instance it works too.

 

[KiwiPlantGuy]

Thiomyl:
Gymnosporangium (Rust)
Puccinia (Rust)
Uromyces (Rust)

Looks like my guess was wrong. Sorry for not having all the facts before posting
Charles

 

[WNC Bonsai]

What about Infuse for use on Japanese maples and tridents? They are not included on the label but it seems to cover a broad range of deciduous trees. The active ingredient is propiconazole.

 

[WNC Bonsai]

Update. Although not listed on the Bonide label all the other product labels do list maples in general as safe for application. I need to get spraying as it has been a really wet season so far and I expect e will see a lot of fungal infections if this keeps up. Last year was very wet and humid and fungus problems were widespread around here, especially leaf spot. I also have a friend whose Austrian black pine needles were a bright orange by the end of last summer.