Fungal infection on cork mount
 

About a year ago I managed to source pieces of natural cork branches which are ideal for growing many epiphytes which have a tendency to roam.
I have recently noticed a white fungal infection growing on the surface of the sphagnum moss I have used to keep the moisture up to the roots while the plants establish themselves. One other piece of cork has developed a thin purple layer of fungus which is spreading across the surface of the cork.
The fungus does not seem to be inhibiting the root growth of the orchid. It just looks unsightly and with time will assist in the degradation of the mount.
Does anyone know how to get rid of this fungus without having to remove the moss and disturbing the orchid roots?

I use neem to prevent fungal rot on my mounts. I would think any fungicide would work but I like neem because its organic.

Thanks for the prompt feedback and advice. What strength do you use and do you spray it on or soak the mount?

I'm a big fan of Physan 20. It never fails.

-J

I would also use Physan 20 but only on the bark...do not soak the new roots and get it away from the new leaf and buds

Thanks for the suggestions. My problem is keeping the antifungal away from the plant and roots as the roots have penetrated the moss so I need to use an antifungal that is plant friendly. Neem might be better in my situation.

Neem oil is a vegetable oil pressed from the fruits and seeds of the neem (Azadirachta indica), an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics. It is, perhaps, the most important of the commercially available products of neem for organic farming and medicines.

Neem oil is generally red as blood, and has a rather strong odour that is said to combine the odours of peanut and garlic. It comprises mainly triglycerides and large amounts of triterpenoid compounds, which are responsible for the bitter taste. It is hydrophobic in nature and in order to emulsify it in water for application purposes, it must be formulated with appropriate surfactants.

Neem oil also contains steroids (campesterol, beta-sitosterol, stigmasterol) and many triterpenoids of which azadirachtin is the most well known and studied. The azadirachtin content of neem oil varies from 300ppm to over 2500ppm depending on the extraction technology and quality of the neem seeds crushed.
It is a good insecticide but it also attracts fungi...because of the oil
better get a fungicide not an insecticide that attracts fungi

Good point Bud. I might just have to remove the moss, treat any residual fugus with Physan and attach new moss.

What about treating it with sulfur powder? you could mix it with water, make a paste and apply it with a brush where the fungal infection is. Sulfur is pretty inexpensive, safe and should dry up the affected area.

Most fungicides that can be bought retail are sold in a liquid form. A very common active ingredient is sulfur, present at 0.08% in weaker concentrates, and as high as 0.5% for more potent fungicides. Fungicides in powdered form are usually around 90% sulfur and are very toxic to humans and mamals. Other active ingredients in fungicides includes the bacterium Bacillus subtilis, and the beneficial fungus Ulocladium oudemansii.