Save My Cymbidium - Mealy/Scale!
 

Hello from Sydney, Australia! I’ve been trawling the forums for the past week looking for answers to help my problem, and thought it was time to post and ask if anyone has thoughts about what I’ve been doing to try to save my Cymbidium from what I think is a mealy bug/scale attack..!

Some backstory..

My husband and I were gifted our Cymbidium for our wedding a year ago, and it has seemed quite happy until about a fortnight ago. Always lush green leaves, and about three or four new shoots last spring – no flower spikes yet though. When we first got her, she seemed crowded in her pot, but my Mum spoke to a nursery and they said Cymbidiums like to be crowded and not to worry.. So I left her outside and hoped for some blooms.

We live in a ground floor apartment facing full west, so we get loads of afternoon sun, and just reflected light in the mornings. It’s been a hot summer in Sydney – a month straight of no rain and 26C+ days. Our balcony has an overhang so even if it does rain, my plants don’t get anything, so I do all the watering myself. No issues so far that I could see, apart from lack of flowers. I occasionally used some fertiliser when watering - Neutrog brand Strike Back for Orchids.

The issue..

So about 2 weeks ago, I noticed white fluff on the Cym. Quite a bit of it on the undersides of leaves and down into the crevices of the leaves near the bulbs. So google told me it was likely mealybugs, and I did find a few actual bugs crawling around. I also have a lemon tree on the balcony which has had some mealy bugs over the past 6 months which I’ve treated with EcoOil and it seems fine. Assuming they crawled over from the lemon..

Although I read you’re not meant to repot in Summer/Autumn, since there is no new growth I decided the Cym needed repotting, after a full clean-up with an isopropyl solution (recipe gleaned online – isopropyl alcohol, water and a little mild dish detergent). I pulled her out of her pot and she was all roots.. After a bit of a hack job – man was she tough to pull apart – I split her, got rid of the dead roots with sterilised shears, and repotted into three new pots, in an Orchid potting mix (Scott’s Osmocote brand in Australia).

Now that I think I’ve cleaned up the mealybugs, I can see I’m now dealing with scale. I don’t have pics of the bug issues as I’ve cleaned them all off, but enough google image searching tells me what I’m dealing with. So I bought some White Oil spray last night and gave them all a good spray this morning.

My question is – will my Cym survive?? I have pics of her now – she has black and yellow mottles all over her bulbs and the bottoms of the leaves. One isn't as bad as the other two. And some yellow spots where I cleaned off the scale, and a few black spots tips on leaves.

Any advice much appreciated! Assuming it’s a Wait And See scenario at the moment..

Thanks!

With mealies and scale, I think your only options are (1) a systemic insecticide, (2) discard the plant, (3) keep treating it with something else until you discard the plant.

Here, I would look for a systemic with Imidacloprid as an ingredient, mix as directed, spray leaves, roots, growing medium, everything. Repeat spraying the aboveground parts at the frequency recommended, for as long as recommended.

Good luck!

:welcomeflowers:
I don't know how badly infested the plant was/is ... For not heavily infested, rubbing alcohol, soap can be effective.

For scale, you can spray well with 70% rubbing alcohol, and wipe all the leaves well with a paper towel. For mealy bugs, spray well with a mixture of rubbing alcohol and water with several drops (or a couple squirts) of dish soap. Repeat at least once a week until you haven't seen any more pests for a couple of weeks, but keep an eye on things.

Or you can use products that OrchidWhisper recommended. You still need to repeat at least once.

Or continue with what you have used, if it seems to be doing the trick, repeat once a week until a couple weeks after you haven't seen any more pests.

I would expect the plant to survive, but if heavily infested, it can be difficult to erradicate the pests (pesticides will be more effective than more environmentally friendly products).

Thanks for the feedback! They are looking the same now - not any worse - after a few days so I will just keep an eye on them and hope for the best. I can't see any more bugs/scale, and I'm just keeping them in the shade. Will update in a week or two with progress!

I agree with OW; you need a systemic insecticide. Topicals are all but worthless in such a situation, as they only kill the insects that are directly sprayed, only affect adults, and have no effect on scale insects protected by their shells or mealies growing on the root system.

I prefer acephate over imidicloprid, but use both.

When in need of a systemic treatment I use imidicloprid. It's easy to find here and practical to use (spray).

I plan to rotate acephate with imidacloprid this year. best to keep the insect's biology off guard. My thought process on mostly using Imidacloprid as much as I have in the past is safety around pets and humans. It is the same stuff as is used in Advantage brand flea control on dogs, except the stuff for dogs is hundreds of times more concentrated. During the USEPA pesticide approval process, I am sure they had to consider pet-to-human toxicity pathways since there is such close contact between people and dogs.

I'm sure safety has been considered carefully with acephate too, but it is probably reasonable that exposure assumptions with acephate might be different than for imidacloprid. Admittedly, these are just "hunches" on my part.

The pots seem quite large for repotting sick plants.

Meh, they will grow into them.

Cymbidiums, especially those with poor root systems, do not like to be over-potted because the poor roots cannot absorb the water fast enough and the media stays too wet too long. This plant has been stressed enough and would be happier in a smaller pot until a new growth is initiated with roots strong enough to absorb the nutrients available.