How to stop fusarium in my collection?

[bateaux_mousse]

I currently have 7 plants that are confirmed or highly suspected to have fusarium. All of them are fairly young plants bought over the past 4 months, four oncidium types, an Osmoglossum, a Caucaea, and a small division of a cattleya. I've also lost one oncidium that had been previously fine and a cymbidium that I only had for a month to a sudden rot, and when I performed autopsies I found hints of purple in the rhizome of the oncidium and the pseudobulb of the cymbidium.

I'm trying to figure out if these issues are coming from the sellers or if they're being infected in my care. I've been buying a lot over the summer, is it just a given that when you're buying orchids regularly a certain percentage will have fusarium?

Or do I have a Typhoid Mary in my collection, maybe an older orchid that's dealing with the infection well enough not to show clear signs but passing it on to younger, weaker orchids? From what I've read fusarium is fairly slow moving, but does it move fast enough in smaller plants to show signs in just a couple of months? My oldest orchid is a cattleya that's been basically doing nothing since I got it about a year and a half ago, I thought for a while that they were just slow growers but I got a couple more earlier this summer and they're growing much faster. I can't cut the rhizome though because the roots have grown over and under it so much that I would be doing a huge amount of damage just to get to it.

I'm also pretty sure that the cattleya division was infected in my care because when I initially cut the rhizome (it was a new purchase from the clearance rack and that part was about to fall off) it definitely had no purple. Whether it could have been infected but too recently to show I don't know, but the main part of the plant is doing very well so I don't think so.

I don't think I'm doing anything terribly wrong that would encourage the spread of infection, I sanitize instruments and don't share water. The sick ones are well separated and being treated, and I wash my hands after handing them. Is there anything I can do better? Do I treat my whole collection as a precaution? Do I treat and quarantine everything coming in? Or just accept that it's always going to be a risk and treat when I suspect an issue?

[Ray]

Improper hygiene is the usual culprit in the spread of fusarium, so if you've been good about that, it seems likely it's an unwanted hitchhiker in plants you are acquiring.

If you want to go the solid pesticide route, purchase some thiophanate methyl, AKA thiomyl or Cleary's 3336.

If you want to go the "organic" route, and to prevent most infections, consider applying Inocucor Garden Solution, which is an assembly of several beneficial bacteria and fungi consortia that consume pathogenic ones. (3 ounces/gallon is needed for a curative treatment, 1-2 for monthly preventive treatments.) It is available at Amazon.com, but shipping is included in the price if you buy it directly from me.

[Selmo]

As ray said two routes you can go or the third route, trash them and start over. Spraying them with either pesticide will not be, a one and done. You will need to spray every 14-21 days for a couple of months and it may or may not work, depending on how serve it is now. How valuable are they to you? Good luck with your route

[estación seca]

A hint of purple might not be fusarium. It seems to me very unusual to buy a large number of plants already infected. I have never seen fusarium in my collection that I recognized.

Fusarium is spread by water droplets, sharing water and tools. Keeping plants far enough apart not to touch, not re-using water and not allowing water to splash from one plant to another is recommended.

You don't say how much experience you have growing orchids. The plants you mention need somewhat different growing conditions to thrive. It is certainly possible you do have fusarium, but my first approach would be to correct growing conditions. Going into winter is unfortunately a difficult time for unhealthy orchids.