Mysterious pest/fungus moving through my collection?

[ramonypony]

It ravages new growths but doesn't seem to affect the mature parts of the plants. It leaves behind thick webs and what I can only describe as "granules." The most affected types are my den phals and oncidiums, I haven't seen it on a cattleya yet.

I just found another victim, Encyclia mariae, and it pissed me off enough to try to figure this thing out. I removed as much of the damage I could and sprayed the plant with Bayer Advanced 3-in-1.

Is it spider mites?? I've never dealt with them before but as far as I know they leave pitting in the leaves and tiny webs, doesn't sound like what I'm seeing.

Enc mariae


Den phal

Onc

[Leafmite]

Could it be the larvae of something? Some larvae leave behind webbing...bag worms for example. The granules might be frass.

The Bayer 3-in-one should work. If not, try Sevin.

[rbarata]

Is it spider mites?? I've never dealt with them before but as far as I know they leave pitting in the leaves and tiny webs, doesn't sound like what I'm seeing.

Probably, but not sure. Isolate the affected plants. Prepare a solution of 1 ltr water+10 mml liquid dish soap+10 ml alcohol and spray everywhere, especially under the leaves. Once a week, for a month. After each spray give a shower bath to the plant, literally. Beware of cold drafts after that.

[ramonypony]

Originally Posted by Leafmite

Could it be the larvae of something? Some larvae leave behind webbing...bag worms for example. The granules might be frass.

The Bayer 3-in-one should work. If not, try Sevin.

I guess it could be. They were outside this summer. They've been inside for a month.

[Leafmite]

I really don't know what is happening. Are you near an Orchid Society? If not, you can send pictures/email here and they will usually help you:

Orchid Pests

The problem is, I just don't know what lives in your area and what pests are common there. A systemic is an excellent first step.

If there is also a fungus issue, I believe the Bayer should help with that, too. Many of these systemics are geared toward roses and they are prone to EVERYTHING.

[Dollythehun]

Oh, my memory is bad. Someone will correct me...could it be "Southern Blight?"

[jcec1]

It looks like caterpillar damage, there are many that produce webbing as a defence against predation. The granules are it's faeces. I would spray where the damage and webbing is. You could just try soapy water and try and flush them out or use an insecticide as well.

[katrina]

Definitely not spider mites. I agree w/the larva comments...it looks like caterpillar damage and plenty of them produce a webbing type material. Obviously orchids are not the first food source for most but if it's the only thing they have to eat...they will eat. Some will eat anything green.

Look for an insecticide that kills other caterpillar/moth larva...my bet is it's some sort of moth larva. This type of pest is usually large enough that you should be able to find it if you look around and in the leaf folds of your plants. Many moth larva tend to eat only the newest growth and can be hidden inside the developing leaves...look around and I bet you find the perpetrator. It'll probably be a cute little inch-worm type critter. Cute...but damn destructive.

[dounoharm]

I concur with katrina.....looks like a tiny crawling moth larva damage.....before bringing in plants from outside, and dunk each one for several minutes in a mixture of soap and insecticide....that helps, but there are always a few 'excapees' that need a sure kill afterwards....

[Tindomul]

It looks like caterpillar frass to me. A fungus will not leave webbing. Damaged areas should also be treated to prevent fungal and/or bacterial infection, start with cinnamon powder and don't let the affected areas stay wet.