Slugs/bugs eating my Ludisia? - Orchid Board

NKOrchid · #1 11-20-2016, 02:43 PM

The past couple of weeks I've been posting a lot. I really appreciate your help - and here goes yet another post!

I just bought a Ludisia Discolor. I've never owned one before, but I had to buy it since it was so cheap (5 dollars)! I bought it in a poorly lit store and I tried to inspect the plants before picking one. However, when I came home and inspected it closely under lights, I think I definitely have a problem. I've never had an issue with another orchid that looked like this, but my guess is that it's some sort of snail or bug?

Here are some pictures of the soil, the plant and the issue:

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Imgur: The most awesome images on the Internet
Imgur: The most awesome images on the Internet

Thanks for reading!

estación seca · #2 11-20-2016, 04:41 PM

It could be insect or gastropod damage. It could also be damage from transport or being handled in the shop.

I would keep it away from other plants and pay close attention. If there are slugs or snails they will make their presence known.

NKOrchid · #3 11-20-2016, 04:49 PM

Thanks for replying!
I guess it could be a lot of different things. I'm really hoping it isn't something that's alive. At the moment I'm keeping the plant away from the rest of my collection. Would using Physan 20 or a mix of water and alcohol help if it's slugs?
A part of me is also hoping that if it is snails, it's old damage and that the snails aren't there anymore... Which doesn't sound too likely to me.

NKOrchid · #4 11-20-2016, 05:22 PM

Jkofferdahl: Wow, that stuff sounds awesome! It's available in a lot of stores, so that's great. Not really expensive either. Do you know how to use it? What amount, what to mix it with, etc.?

NKOrchid · #5 11-20-2016, 05:52 PM

Great! I just read about it and what it's supposed to do is dehydrate pests. It's also effective on slugs, but less effective because the more moist the environment the less the DE works. Do you know why it doesn't have an effect on the plant? Why doesn't it dehydrate it too?
Great advice!

estación seca · #6 11-20-2016, 06:29 PM

I'm not so sure I want sharp diatom skeletons getting into my stomach and intestinal crypts.

NKOrchid · #7 11-20-2016, 06:31 PM

I trust what you write and I know wikipedia is far from always right, but here's what it says (which is where I got my information from):

Diatomite is used as an insecticide, due to its abrasive and physico-sorptive properties.[10] The fine powder absorbs lipids from the waxy outer layer of insects' exoskeletons, causing them to dehydrate. Arthropods die as a result of the water pressure deficiency, based on Fick's law of diffusion. This also works against gastropods and is commonly employed in gardening to defeat slugs. However, since slugs inhabit humid environments, efficacy is very low. It is sometimes mixed with an attractant or other additives to increase its effectiveness. The shape of the diatoms contained in a deposit has not been proven to affect their functionality when it comes to the absorption of liquids; however, certain applications, such as that for slugs and snails, do work best when a particular shaped diatom is used.

As far as I understand (my native language isn't English) that's not the same as what you're saying. However, what you say sounds way cooler and more effective!

Orchid Whisperer · #8 11-20-2016, 08:12 PM

Quote:

Originally Posted by NKOrchid

Thanks for replying!
I guess it could be a lot of different things. I'm really hoping it isn't something that's alive. At the moment I'm keeping the plant away from the rest of my collection. Would using Physan 20 or a mix of water and alcohol help if it's slugs?
A part of me is also hoping that if it is snails, it's old damage and that the snails aren't there anymore... Which doesn't sound too likely to me.

Physan is a disinfectant, not a pesticide. Alcohol that is not applied directly to the pest could do more damage than good.

My guess is that it is slugs or snails. Try a slug bait such as Bug-get-a (Ortho's brand of metaldehyde) or another slug bait.

Leafmite · #9 11-21-2016, 12:34 AM

You can also soak the entire plant for a few hours in a bucket of water, first (if the plant is blooming, though, it might not be a good idea to submerge the blooms). That will help to drown anything that came with the plant. Then, when the plant is dry, use the Diatomaceous earth.
Someone told me that Diatomaceous earth is mostly silica and, like those little packets that come to help absorb moisture, it has a drying effect on critters by absorbing moisture. No idea if this is true but my hands felt rather dry after using it (I know, I know). It doesn't seem to hurt the blooms of my orchids or citrus which is a real bonus.

I am quite pleased with the Diatomaceous earth. It is killing scale, mealy, pill bugs and I do not see any spidermite on the two alpine strawberry plants that I brought inside to enjoy (also treated) and they usually have issues with that and are, therefore, grown with the passiflora (this year, they are under lights, instead). I noticed that one of my citrus had a bit of stickiness on a leaf but there is no sign of scale/mealy bugs so I think that it killed either young scale or mealy bug. I did do a second application on a few plants. With so many plants, I have quite a bit of sources for things....

This is my first experiment with the stuff so I cannot say how this will work long term but with the stuff I grow, I am hoping that Diatomaceous earth will be a good solution.

NKOrchid · #10 11-21-2016, 05:11 AM

Jkofferdahl: I see. Well, I'm definitely buying it. I guess it's worth testing since it's quite cheap.

Orchid Whisperer: Someone recommended to try 1:3 alcohol/water solution, when I had an issue with some brown/black spotting and a possible fungus problem. I had three plants that were obviously infected. One I threw out, since it was so infected I didn't want it in the same apartment as the rest. The two others I started treating with the alcohol solution. I've treated them twice now during one week and it doesn't seem to affect the plant, however I could be wrong and the plants could get damaged somehow along the way of the treatment. The Ludisia I'm not treating with alcohol yet and thanks to your comment I wont, since (as far as I understand) it would not help one bit. Thanks!

Leafmite: The Ludisia is blooming, but the buds hasn't opened yet. It has three stems with buds. I could submerge it in water to the point of the buds, just to be safe. Does submerging it in water really kill everything? All pests, slugs, bugs, fungus?
Have you ever damaged a plant by submerging it? I will definitely try submerging it in water and then treating it with DE. Sounds like a pretty effective solution!
If this seriously has no effect on the plant, I'm considering doing it to all my plants, since they're all at risk of having some sort of mite/fungus problem after I added an orchid to my collection that later showed to be in pretty bad shape and the issue was spreading to other plants. Thanks for the great advice!

Do you guys use a specific brand of DE?