orchid fusarium on Vandas

[UK Orchid lover]

Hello everyone,

I was wondering if anyone can give me some information on how to spot fusarium wilt on vanda orchids. I lost my first vanda to this disease (It was wilting and had the purple ring in the stem) I am scared to buy more as I am not sure on how to spot the disease.

can any one please share some images of infected plants or the most telltale signs of this disease on a vanda please?

thanks

[camille1585]

Fusarium wilt infection can't be conclusively determined at a glance, and a diagnostic is usually made at a rather late stage, when the plant is doing poorly and the plant is cut into. The fungus eventually kills the plant by clogging up the vascular tissue, so other than that famous purple ring, plants looks dehydrated and may have some yellowing. But those may also be symptoms of a plant dehydrated for other reasons, like underwatering or root rot.

There are lots of cases were plants have a low level infection, yet grow and bloom normally for years. It's also good to know that the purple coloration can be natural in some plants, so that should be examined in relation to other symptoms on the plant.

My advice to you is to not worry about it too much. Yes, the disease exists but it's not everywhere. It's something to be aware of, like many other orchids diseases. The best course of action is the same for any disease: don't buy any orchids which are visibly unhealthy, and try to buy plants from reputable nurseries. The care given at home is also important, don't dunk/soak plants in the same water, sterilize cutting tools between plants...

[King_of_orchid_growing:)]

Don't bother trying to spot the disease. As was mentioned, this disease is rather difficult to diagnose visually at a glance.

Fusarium is rather rare. If you grow your Vandas on the warmer side (60 F - 90 F/15.6 C - 32.2 C), and if they are given a fair amount of indirect light (bright indirect light - if you've grown Cattleyas before, that is as bright as they can be grown), they should do very well. If you're using artificial lights, I recommend an LED light that is rated to produce about 1,200 lumens - 1,700 lumens, 20 PAR - 36 PAR, and 5,200 Kelvin (K) - 7,200 Kelvin (K) nothing less (wattage is not as relevant a parameter). They can be grown bareroot or potted in large grade bark. The roots need to dry out before watering again. If they are grown bareroot, you may need to water daily. If you're growing potted, watering regimen is less (twice a week is fine if you are growing indoors).