Fusarium
 

Anyone ever had to deal with fighting Fusarium fungus in their collection? I had to discard about 20 plants yesterday that all looked like the picture of health-some in bud others in spike-it was hard. When I cut the rhizome to inspect, there was red in the rhizome and some with the tell tale ring around the rhizome indicative of Fusarium..... any fungicides that would get rid of it?

Benomyl WP

Fusarium????? I've never heard of it. OMG, it must have broke your heart to have to throw out orchids. So what made you cut the rhisome to find out what you had? Was there a tell-tale sign to make you do that? I'm so curious about this. All new to me.

I will not comment on whether you really had fusarium or not. The most normal Symton is darken pseudobulbs from the rhizome up. You did not mention you had these signs.

Fusarium is a common fungus and it exists ever where in the world. It is a constant fight. It spreads by hands, water splashing and contact of plants touching each other.

Commercially it is treated with a number of fungicides. The fungicides are all expensive and need to be rotated. None of them should be used more than twice a year.

The old recommended treatment was Thiophanate metyl and iprodine. They have been used so extensively that they no longer work. Most strains of fusarium are resistant to the drugs.

The QOL inhibitors are the newest attack but very expensive. The best is Heritage and it costs $500 a pound wholesale, not to mention it is very dangerous like most of these drugs. The manufacturer literature warns using it more than twice a year creates drug resistant strains.

Compass by Bayer $100 a pound and Insignia by BASF $150 a pound are cheaper and similar but not quite as good. These three are all QOL drugs and you can not rotate among them. You must use a different family of drugs.

None of these will cure fusarium but are used commercially as a prevention of the disease spreading.

The only treatment if it is an important plant is to cut the infected sections back to good tissue. Normally they go directly to the burn pile.

I have been using Companion brand Bracillus bacteria which is a natural innoculate against fungus. After one year of regular use the rate of fusarium is way down. Even when it comes in with new purchases it does not spread to the older plants which were treated. I do however destroy infected plants immediately.

Thank you Jerry for your time in explaining what it is. I would like to see a picture of it, whether in a book or from someone's camera. Just to see what to look for. If anyone has one to share (a pic, I mean) please do. It's a very scary thought to have to deal with this type of disease.