Yellowish lines and curves on leaves

[Tilly]

Hello Everyone,

This is my first post and I am hoping that you can tell me what is wrong with my orchids!

I have fourteen plants and they are all suffering, even the two that I keep apart from the other twelve. Several leaves on each plant have the problem.

I have tried to take a close up picture of the underneath of one leaf, which seems to have regular, almost geometric shapes. This makes me think it is some sort of pest?

Also, the edges of some of the leaves seem to have a sort of "curve" (not very easy to explain)

They have had this problem for a few weeks, but it seems to be spreading - but only on the orchids. I have a large collection of succulents and so far so good.

Any help VERY gratefully received

Many thanks

Tilly xx

[Orchidtinkerer]

Hi welcome to ORchidboard Tilly,

if had to guess I would highly suspect that to be insect damage, well and you seem to have broken the leaf in at least 3 places trying to take the picture as those are fresh leaf splits. Try not to damage the leaves.

Have you got some insect spray for orchids? Hopefully someone who recognizes the pest that did this can help more, I am 99% sure insects will have caused this but I've not seen this kind of damage before so not sure what would have caused it.

edit: there is also no need to cut off a completely green leaf from the plant, phals take up to 1 year to grow a single leaf, cutting it should be a last resort.

[Tilly]

Thank you very much for your reply. Yes they are fresh splits in the leaf.... it was a bit difficult to take the picture, and I did end up cutting it off. I thought getting rid of a diseased leaf was a good idea? Mind you, on some of the plants there are so many strange leaves that if I cut them all off there would be none left. I shall go to the gardening centre today to see if they have any spray. I didn't know it took so long for a leaf to grow - interesting!
Thank you again for your hel^p.
Tilly x

[Fuerte Rav]

Hello Tilly
I had what looks like exactly the same a couple of years ago. The curved edges on the leaves and the dried out marks/lines on the leaves. I also found honey dew drops on the under perimeters of the affected leaves.
I never discovered exactly what pest it was but I did treat the plants successfully using advice from OB.
I bought pure Neem Oil and Horticultural liquid soap online as a package. Followed their directions for mixing and sprayed every surface of all my orchids, tops of leaves, bottoms of leaves, stem, crevices and the top surface of the media they were in. After leaving in a gentle warm breeze for an hour I made sure all remaining liquid was removed from the crown and crevices so as not to encourage rot. (A piece of tissue folded into a point does a great job!) All the decorative pots, shelves etc also got a wipe down. I repeated this 3 times at weekly intervals to make sure I caught the bugs at all life stages.
The affected leaves don't look pretty but are strong and green - eventually they will become the oldest ones that drop naturally - in the meantime they are still doing their job.
In my environment there is a good chance the pest was a form of scale/mealy bug/cochineal.
Pure Neem Oil wasn't cheap but a little goes a long way. I haven't had any repeat problems but I spray every month or two, just in case. A bonus is nice bright, shiny, clean leaves!
Neem Oil has quite a strong smell, I quite like it but others don't. It disappears after a day or two!
Pictures show top of leaf, bottom of leaf, happy orchid x 2.








Good luck!

[Tilly]

Good morning, Fuerte Rav - thank you very much for your reply. That is exactly what is wrong with my orchids. Other than the weird leaves, they are in good health, apparently. I did have an invasion of mealy bug about a year ago and treated it with "savon noir", which is a natural soap and that did the trick, along with a cotton bud to get into the cracks. I have heard of Neem oil, but don't know if I can get it in any shops nearby. I'll have a look on internet. I have given them an inspect spray and I'll give them a dose of "savon noir" later in the week. I'll let you know how I get on. Again - thank you very much indeed for your help. Tilly x

[Fuerte Rav]

This is the combo I bought online - from UK and delivered to Spain.

Neem Oil & Soap Repellent

[Tilly]

Thank you! I'll try the "savon noir" and if it doesn't work I'll try the neem oil.
Tilly x

[Ray]

Having never seen them first-hand (knock on wood), I cannot be certain, but I recently read an article posted by a Dutch commercial grower about thrip damage becoming an increasing problem in their phalaenopsis/anthurium nursery, and the damage they showed looked similar.

EDIT: Found the link so you can decide for yourself.

[Tilly]

Thank you, Ray, that is very interesting. It is definitely thrip damage on my orchids. I looked it up in French and it is the same word and I saw on a French site that "savon noir" should work. Apparently they do not like humidity so I am now going to take them into the garden and give them a savon noir shower!!
Thank you!!
Tilly x

[Fuerte Rav]

Originally Posted by Ray

Having never seen them first-hand (knock on wood), I cannot be certain, but I recently read an article posted by a Dutch commercial grower about thrip damage becoming an increasing problem in their phalaenopsis/anthurium nursery, and the damage they showed looked similar.

EDIT: Found the link so you can decide for yourself.

Certainly looks like it and goes along with me not being able to find what I thought were the likely culprits such as scale or cochineal.
Thanks Ray, really useful!