RE: Selmo

This damage happened back when this leaf was just a small shoot. When the shoot was young something took a bite out of side of the shoot. The new shoot has the leaf rolled up inside of itself. And when the pest took a bite, it was out of several folds of the leaf. Kind of like when you make snowflakes out of paper. Some kind of chewing pest; caterpillars, grasshoppers, or mice or even lizards can leave this kind of mark.

Exactly what happened, shoot tip was cut when it was tiny and has grown with the square cut on top. Okay, may be a chewing pest, but it must be a nano sized pest - I can't find em...:scratchhead:.

Also when you transplanted it could you of hit the new shoot with something that damaged it on the side.

No - just transplanted it to S/H yesterday.

But being that you said it was inside, then probably snails or a slugs. They can bring infection with them, as they chew on the leaf. The outer leaf was eaten though. The inter leaf rolls suffered the infection from the injury. Giving it that repeated pattern.

Indoor snails or slugs? Again, must be nano sized, I just can't find em, but I'll keep looking.


The leaf will probably not be effected any more by this. The leaf will just be unsightly for a few years until it drops off after it is replaced by new leaves.

Hope this is true... but the new inner leaves are damaged as they form...never to mature.

There are snail and slug baits that are effective, or you can use the old beer in the plate to trap/drown them.

Nano baits for nano slugs and snails?:scratchhead:

Good luck with this and Welcome to the forum!
And what cool name for a cattleya

Thanks, the name for this Cattleya was on the tag that came with it when purchased... Wild Willie Bingo.

Your fertilizer and your RO water lack calcium. That may be the problem with the new shoot blackening. They also lack magnesium.

I mix my municipal tap water (high in dissolved solids, mostly calcium and magnesium carbonates) with rain water so I give my plants calcium. Depending on your tap water you may not need to water all your plants with solely RO, and you might be able to mix tap with RO to avoid dealing with a calcium supplement.

Go to your water utility's Web site and look for the annual water quality report. Let us know what it shows - it might list some or all of total dissolved solids, calcium content, magnesium content, hardness, alkalinity.

As for tiny snails - look up bush snails. They are tiny. If you have them in your collection you might not know it. They do not always take commercial snail bait. They can be killed with caffeine by pouring cooled strong coffee through a just-watered pot, so the medium and roots are already saturated with water. Wait an hour and water again to rinse out the coffee. If you have bush snails in at least one plant you will need to treat your entire collection. Caffeine can damage dry orchid roots, so be sure you have just watered the plants before treating with coffee.

Update on Wild Willie Bingo - Leaf Spots
 

Over nine months have passed since my original post and I'm happy to say I'm no longer experiencing cut leaves. However numerous leaf spots have appeared on what otherwise appears to be a healthy plant growing in semi-hydroponics. If fact, a new flower spike is emerging.

I've treated the leaves with a combination of both Physan 20 and Pyton 27 bacteriacide-fungicides and the leaf spotting condition has only worsened.

The spotting issue usually begins at the leaf tips and spreads down to the lower part of the leaf. I cut off the leaf tips for fear, whatever this issue maybe, that is would spread throughout the plant.

Any ideas or suggestions would be appreciated.

Some Oncidiums are known for having lots of spots. You're using relatively pure water, however, so that eliminates the most prominent cause of leaf spots. And they usually aren't so necrotic, with large depressed areas.

I suggest not using fungicides unless you know what you're treating. It kills off beneficial organisms that inhibit pathogens. And many fungi are resistant to various fungicides. You need to know what is the fungus and whether it's susceptible to the fungicide used.

I rarely say this, but I suggest you go to the diseases section of the St Augustine Orchid Society Web page and look at the virus photos. It's impossible to tell whether a plant has virus infection without a test, but in your conditions I think it's a possibility.

You could also take a piece of leaf to a local university or your Agricultural Extension office. They may be able to look at it under a microscope and identify the problem.