Fungicide safety for orchid use
 

First, this is a bit of a cross post, but I haven't gotten any feedback in the beginners section. Sorry.

There seems to be a lack of options for fungicide where I live this time of year. I tried to find copper but could not so I ended up with Spectracide immunox. The chemical in it is myclobutanil.
Has anyone used this on their orchids? If not and I decide to experiment does anyone have tips?

Thanks in advance.

I haven't used that one but I've used a couple different premixed fungicides in the spray bottles from Home Depot that were designed for use on flowering plants. Neither of them caused any harm to the orchids.

I use Hy-san, eco friendly fungicide. Whatever the orchid nurseries use.

Hi, Firstly, do you know that you need a fungicide ? What is the problem you are trying to solve? There are quite a few fungicides available to orchid people, however, some target different pathogens. Phyton 27, Physan, Dithane M-45 and a host of others are good for taking care of most of the problems. They are all available online, too!

I use Dithane M-45 as a fungicide and Physan as a preventive.

As a preventive measure, I highly recommend Zero-Tol. It is a great broad-spectrum, contact algaecide/fungicide, and exhibits no phytotoxicity whatsoever.

I am having an issue with black root tips. A fungus was the only theory I got that I haven't already checked for. here is a link to the original thread: http://www.orchidboard.com/community...root-tips.html

If anyone in this section has any other ideas I would love to hear them.

Thanks for all the input so far!

I had a problem with root tips turning black and turned out to be the water. Went to ro and problem solved. Your water may be soft but you can still have high TDS. You need to find out what your TDS is. TDS meter aren't that pricey and give you good feed back on what to do.

Do you have a water softer?

No, no softener, it comes that way out of the tap. I do not know my tds, that's one of the few water tests I don't have. I'll see about getting one.
With as much as it has been raining I have not been watering much but the problem has become much more widespread.

I tried the spray on 2 orchids that I'm not in love with, we'll see in a couple of days how safe it is.

Sounds like you have your hands full!!!! I don't miss those days.

Words of caution..... Moisture will spread a fungal problem like wild fire. You may have to take extreme measures now to avoid a disaster.... I feel your pain.... No fun.....

Do you know if there's a difference between Zerotol for pro's and the Zerotol RST?

Just the concentration of the as-shipped product.

Zero-tol in the 2.5 gallon (smallest) container is 27% active ingredients, which being oxidizers, makes it a DOT hazardous material for shipping. The RTS (Ready To Spray) quart bottle is 6.7%, making it non-hazardous.

The application concentration would be the same, so when I refill the RTS bottle from my big jug, I make a 25% solution to use in the 150:1 RTS sprayer.

Thanks for the explanation Ray..... I'll be on the look out.

Remember, many orchids do not grow in the ground but on trees or rocks and their roots are adapted to having plenty of air flow. If you are having fungus problems, perhaps using a more open mixture (large lava rock) and net pots or baskets would help. This helps provide humidity around the roots without providing the conditions in which fungus can grow. Black roots could also be a sign of 'toxicity' to something in the water or too much fertilizer as others have mentioned. If you've corrected things concerning the water, the problem will go away once the offending substance is diminished enough in the medium. Changing or flushing the medium well with pure water will help if this is the culprit. Good luck!
Leafmite

Reporting back:
Looks good so far. I started with a couple that had been badly sunburned and I figured they were pretty much goners anyway. Well, they are not only still alive, they look like they are starting to recover. I've sprayed several since and so far no sudden deaths. I don't know if it is the fungicide or that it's been insanely dry but I haven't seen any new black root tips.

While I appreciate that 99% of root problems are actually medium and pot problems, most of the roots I am seeing this on are not in medium or pots. Most of my plants are mounted or in baskets and none have been in their current situation longer than 7 months. I have included a picture so you can see what it looks like. Sorry I didn't post it sooner, life can sometimes be too "interesting" to follow up on things like hobbies.

http://i68.photobucket.com/albums/i1...ds/aroots3.jpg

http://i68.photobucket.com/albums/i1...ds/aroots2.jpg

http://i68.photobucket.com/albums/i1...ds/aroots1.jpg

They look great. Whatever you have been doing it is working!

Fungicides safe for orchids.
 

I have used chlorothalonil on orchids including Dendrobiums with no ill effects. Some people will be familiar with this material under the brand name Daconil. It can also be found under many other names including "Ortho Garden Disease Control".

People here routinely report using mancozeb also known as Dithane and many other names and I used this on all my plants a few weeks ago with no ill effects.

People here also use Thiomyl also known as thiophanate methyl. It is a systemic so I have just bought some of it.

Both Mancozeb and Thiomyl can be purchased on the internet in small quantities.

Mancozeb and Thiomyl are often used as a mix to give a broader spectrum of activity.

Thiomyl is also one of the 2 fungicides in Banrot.

I read this thread with interest since I believe hobbyist use way too much fungicide most of which do nothing.

Your last photo was the proof. You have a normally growing orchid and the tips of the roots turn black when they stop growing from a variety of reasons.

I your case it is the method in which you potted in a basket with sphagnum. All the moisture is around the basket and the roots in the air are not receiving enough water to continue growing. The moisture is around the basket and the plant finds it easier to get the water there. That is the reason for all the new roots closer to the basket.

This is very noticeable on Vanda.

It is a natural growth pattern and you would have been fine doing nothing. All the fungal products mentioned here are bad poisons and should be avoided whenever possible.

Can I ask what products you prefer?

I think that what Jerry is saying is that he believes that hobbyists often use fungicides when they are not needed (and thus the fungicides do nothing).

Hi ! The query was founded about the fungicides. The eveidence is in the back rotted roots in the pics. Which exact pathogen is not evident.

All of the products you and other people are talking about are well documented to help control specific problems. They are NOT poisions if applied correctly for the problem. Problem is to get a right diagnosis. Ive been growing for over 30 years in many locations and used all of them with success on orchids. Good luck to 'Tolumnia' with the plants!

I think the number one lesson everyone should learn is quarantine all new arrivals to your collection! I always keep the new plants lumped together. So there is no possibility of water spattering from new plants to my collection. I tend to the collection before I ever touch the new ones. They are the last on the list for anything.

I think Martin Moates says it best:

He does advocate a proper spray program of fungicides.

To answer the questions directed to me --

I use three natural products (Companion, Essentials -rooting hormone- Vermi-liquid worm secretions added essential microbes), the most effective for fungal control is Companion brand of Bracillus bacteria made from seaweed. There are other products that use bracillus bacteria in different combination and I assume they all work about the same.

It does not kill fungus and I personally do not believe any of the products effectively kill fungal problems. Bracillus bacteria is natural anti-fungal inoculate. It stregthens plants to resist the disease. The best cure is to never get the problem.

After using Companion for three years I went from destroying 380 seedlings (out of 4000 new ones) three years ago to 80 the next year to zero the third year. This season despite twice a day rains including a rain after dark each day (everything is outside under shade cloth) I have destroyed only 6.

Fungicides are applied commercially as a preventative mostly to control spreading from an infected plant to healthy plants. Diseased plants are destroyed not 'saved'.

The biggest problem with hobbyist use is that the items offered for sale have been used for so many years the fungi have evolved to be resistant to the products.

What hobbyist fail to realize is that these products are not to be used more than twice a year. Commercially, if more treatment is desired, the products need to be rotated between at least three different types of fungicides. That does not mean three different 'names' but three different classes of drugs that work differently.

The newer drugs are effective to prevent spread but very expensive. Heritage is the best but $600 a pound. Even with 12,000 orchids and new purchases every week, it is not commercially viable for me. Destroying diseased plants is the economical method.

For hobbyist the best and least expensive treatment is a fan. Good air circulation is the best prevention.

Being a hobbyist I care more about _not_ destroying plants than I do economy. That is why for use as fungicides I have chlorothalonil, mancozeb, myclobutanil, thiomyl, Heritage and Captan.

For miticides I have abamectin, Floramite, Tetrasan and Talstar.

For insecticides I have azadirachtin, abamectin, spinosad, imidacloprid and Talstar.

and what do you use for all the nervous twitches you have from using all these chemicals?

This thread has gotten me to produce a tutorial with photos of fungal issues. You can find it on my web site

Pythhion and Fusarium fungus on Cattleya

I think that for the fear-mongers the best quote is from George Carlin: "Saliva causes cancer, but only if swallowed in small amounts over a long period of time..."

...um..you all just swallowed again.

Wow this thread has turned so interesting. Thanks for all of the feedback!
If you had plants that looked like this what would be your guess as to they problem? I should note that since the weather has gotten REALLY hot and dry (which means I am watering with the hose every day) the problem seems to have stopped progressing. Even on plants that had it but have not been treated in any way. And all of my plants have been putting off new healthy roots like there is no tomorrow. I think this officially rules out the water as a problem.

I'd love to hear something about fungicides that are easily available in Canada. By that I mean something I can purchase here rather than ordering from the US. Any good suggestions?

:)