Oncidium Sharry Baby rapidly declining - pests, black and yellow spots, few roots - Orchid Board

DebontheBackstreet · #1 08-19-2023, 11:12 AM

Hi there,

I’m new here but not new to the orchid world - I’ve been growing phalaenopsis orchids for nearly three years and six months ago I purchased an Oncidium Twinkle as I heard it was a good starter oncidium. It’s been doing well (currently has two developing flower spikes). So I added a Sharry Baby to my collection about 7 weeks ago. Only it’s been problematic from the start and I made a couple of rookie errors.

The Sharry Baby came from a nursery that I trusted and I’d previously had very healthy plants from them - it was an online purchase. Being new to oncidiums, I thought that the shrivelled pseudobulbs and accordion leaves were due to the fact that the plant had been in transit during hot weather, but I had trouble rehydrating them. The plant had three developing pseudobulbs as well as several mature ones. A couple of weeks later, I noticed a bush snail on the plant and also that one of the leaves was developing an infection (it was yellow and mushy). I spoke to the nursery for advice and treated the infection. They advised also to treat the snails by picking them off the plant. I also asked about the spotting I’d noticed on the leaf tips and was told that it was connected to misting and high humidity in the nursery but all was fine. The infected leaf spread to the pseudobulb and so I spoke again to the nursery - I was advised to repot and remove the infected pseudobulb. This I did.

When I unpotted, I found many snails and they had eaten pretty much all the new root growth, leaving me with only the old roots, which were around a moss ball. My rookie error was that I didn’t realise there was a moss ball and I was watering when the coir was dry, which led to overwatering and probably accounted for the infection. So I lost most of the roots but was optimistic due to the new growths. I had noticed that one of the mature bulbs was wobbly - it’s growing a little bit away from the rest of the plant - and that the rhizome felt flimsy, so when I repotted I staked the plant to try and help it stay together. I removed some of the papery sheaves so I could check for pests and spray with hydrogen peroxide 3% and noticed holes, probably from a pest, in one of the pseudobulbs. A week later, the rhizome was still wet from watering - the root ball was holding on to moisture, so I thinned out the remaining roots to help the rhizome dry out between watering. This has worked well.

I also removed the flower spikes and put them in a vase. A few days ago, I noticed that the flowers had mealybugs and I saw a pinkish thing on the plant, which I suspect is a young mealy. Today I found more signs of pests - a black thing and sticky substances on the leaves. I’m treating the mealies with hydrogen peroxide 3% and rubbing alcohol.

The repot was about three weeks ago and the plant was stable until Monday when the rapid decline started - . pseudobulbs, leaves and one of the new growths are yellowing. I’d been watering very lightly since the repot, keeping the media moist but not wet and added a layer of lightly misted sphagnum around the developing roots. I’ve also noticed yellow spots on the leaves and black spots too - photos are attached and I wonder if anyone could advise me on whether they are signs of infection, viruses, disease or more signs of pests? If disease/infection, could the rest of my orchid collection be at risk? I’m sanitising my hands and tools before and after touching this plant and it is isolated but I live in a small flat.

I honestly feel like this plant has so many problems it may be time to consider condemning it and starting again with a healthy plant (I’d probably get some more twinkles to help me recover my confidence).

Any advice or thoughts would be much appreciated. Thank you so much if you’ve read this far.

Ray · #2 08-19-2023, 02:39 PM

Hi, Deb.

Welcome to the Orchidboard.

Personally, I wouldn't give up on it yet (but I would ask for my money back from the vendor).

If you can find a suitable treatment for the snails, which are likely the primary problem, you might be most of the way home. You might try this:

Thoroughly spray the leaves and bulbs with rubbing alcohol, as that is likely to kill the insects, then submerge to pseudobulbs in cold coffee for a few hours. The caffeine is supposed to be toxic to the bush snails. Metaldehyde is a known bush snail toxin, but may be difficult for a hobbyist to acquire.

After that, warmth, humidity, and shade can help it grow new roots. If you can find Kelpak, definitely get some. If not, a liquid rooting hormone is a reasonable substitute.

Immerse the entire plant for about an hour in tepid water containing either of those products, if available, or just plant water. Pot it up - staking it so it won't wobble - in your medium of choice, water it in with that solution, then invert a clear plastic bag over it to trap humidity and slow desiccation.

If it survives, in a few weeks it should grow new roots (especially near the emerging pseudobulb) and you can treat it normally.

estación seca · #3 08-19-2023, 06:58 PM

Welcome. I second everything Ray said. This orchid can take an amazing amount of abuse and survive. You might wind up with a much smaller plant or plants, but they should eventually flower.