Brassavola seedling leaves got blackish lines along midrib

[Roberta]

I'll jump in with my ... Scale definitely can develop a shell (not baby scale)... underneath would be eggs that can develop into more scale. A fungicide is of no use whatsoever against scale, which is an insect. For a first pass, clean the leaves with soapy water (a few drops of dish soap in a sprayer of water works) Does that remove it? then spray the leaves in all the crevices, leave them drippy wet. If insects, the soapy water clogs their pores and drowns them. The treatment, however, only work on the adults, likely not larvae and certainly not eggs. So the treatment needs to be repeated over multiple weeks. Scale, however, is very stubborn - it that's really what it is, time for an insecticide, preferably systemic like Bayer's. And THAT also needs to be repeated. If it is actually a pest, it is NOT one and done.

[estación seca]

I believe that is juvenile scale. It looks worse than the previous photos. I have successfully treated it on seedlings by drowning them. Completely submerge the entire seedling in water with just a little bit of dish detergent, just enough to form a few bubbles. Leave the plant submerged for 6-8 hours. I use longer soaks for some larger orchids. You may need to unpot it. I would throw away or bake the potting media because it probably contains scale now. Clean the pot, too. Then gently brush off debris on the leaf and rinse in fresh water. Repot. If a seedling is planted in moss I will submerge the whole plant and pot.

[sweta]

Originally Posted by estación seca

I believe that is juvenile scale. It looks worse than the previous photos. I have successfully treated it on seedlings by drowning them. Completely submerge the entire seedling in water with just a little bit of dish detergent, just enough to form a few bubbles. Leave the plant submerged for 6-8 hours. I use longer soaks for some larger orchids. You may need to unpot it. I would throw away or bake the potting media because it probably contains scale now. Clean the pot, too. Then gently brush off debris on the leaf and rinse in fresh water. Repot. If a seedling is planted in moss I will submerge the whole plant and pot.

Oh no😭 it's so hard to identify scale. Why dont I see any insects moving.? Ok I guess I will have to drown the entire plant in soapy water. Do the roots also need to go into the soapy water? Wouldnt the roots die? And how do i clean the any scale that is stuck without damaging tender leaves? Also if the water gets into the leaf joins wouldnt it cause stem rot?

---------- Post added at 07:04 PM ---------- Previous post was at 06:55 PM ----------

Originally Posted by Roberta

I'll jump in with my ... Scale definitely can develop a shell (not baby scale)... underneath would be eggs that can develop into more scale. A fungicide is of no use whatsoever against scale, which is an insect. For a first pass, clean the leaves with soapy water (a few drops of dish soap in a sprayer of water works) Does that remove it? then spray the leaves in all the crevices, leave them drippy wet. If insects, the soapy water clogs their pores and drowns them. The treatment, however, only work on the adults, likely not larvae and certainly not eggs. So the treatment needs to be repeated over multiple weeks. Scale, however, is very stubborn - it that's really what it is, time for an insecticide, preferably systemic like Bayer's. And THAT also needs to be repeated. If it is actually a pest, it is NOT one and done.

I tried the fungicide thinking it could be fungal infection but that doesn't seem to be the case. I hate scale, I've tried bonide systemic fungicide on some of my mature orchids to remove scale and I still dont seem to have gotten rid of it after 2 -3 applications. I'm really tired of dealing with scale issues. Maybe I should just toss my entire orchid collection😱

[Roberta]

Fungicide won't do anything to scale. So let go of that idea. Fungicide addresses fungi (and not all fungi... you have to know what you are treating and choose accordingly.) You can soak the whole plant - roots and all - in soapy water, won't hurt the roots or the plant. The soapy water plugs the pores in the bodies of the insects through which they get oxygen, you're drowning them.

But if were my plant, i would stop messing around with home remedies, time to get serious and bring out the big guns. Scale is stubborn. Bayer's BioAdvanced is a good place to start. And you can soak the whole pot in a solution of it, diluted according to the label. After you have done that once, then you need to spray the plant thoroughly (both sides of leaves, into the crevices) every 5 -7 days at least 3 or 4 times, because it doesn't touch the eggs - which hatch and then you need to nail the next generation.
And you also get the survivors from the first treatment. And do that a few times to get the population down to "very small", never will it be zero. So two fundamental concepts to keep in mind when going after insects:
1. Choose an appropriate treatment that is suitable for the target. (hot tea won't cure pneumonia and antibiotics won't cure viruses and fungicide won't cure scale) If you are going after an insect, use an insecticide. IF mites, use a miticide. If fungus, use a fungicide,
2. Repeat the treatment several times, to attack subsequent generations.

And there is a "3" to keep in mind... ideally, you have more than one chemical, with different mechanism, to rotate into the schedule, which also can get individuals that might be resistant to the original treatment. Others will have suggestions of favorite pesticides. But if you do both 1 and 2, you will eventually prevail.

[sweta]

Hey @Roberta I already have the bayers bio advance 3 in 1 spray wondering if I can it as a systemic pesticide to kill scale? Or do I need to buy the one that says systemic? Ingredients look same in both. I dont really want to invest in another systemic insect killer as I've already invested in Bonide acephate that I used on some of my phals to treat scale and most of those phals haven't been doing well. I treated the phals with bonide 2-3times every week and also drenched them in soapy water. I didnt soak them for long time though. And some of my healthy phals developed stem rot even after I did everything to let water drain out of leaf joins. Also with the acephate treatment most of the phal roots just shriveled and died. I'm not sure how strong the bayers bio advanced systemic insecticide is and if it will have similar effect on the roots. Only Oncidiums did well despite the 1 strong treatment. Most phals are gone. I wonder if its just easier to throw these plants away rather than deal with all these harmful chemicals. I had breathing issues when I was treating my orchids with acephate. Even though I did it outdoors with a K95 mask on still it was really uncomfortable. I think bayers one is a bit better though in terms of smell. I'm already feeling stressed thinking of again treating the orchids and even after all the treatment I wonder if there scope of fully eradicating scale😞How can i clean up my grow space so any new orchid collection I plan to build wont be affected by any scale survivors.

[sweta]

Also do you think bonide systemic granules with imidacloprid might work better than concentrate?

[Roberta]

The granules might just do the job - and not put anything n the air. Suggestion... start with the soak that ES suggests. Get the plants cleaned up. Then use the granules for longer-term protection to keep them clean. And keep an eye on the plants... if you see further sign of infestation, pounce right away. Scale is awful.

[sweta]

Originally Posted by Roberta

The granules might just do the job - and not put anything n the air. Suggestion... start with the soak that ES suggests. Get the plants cleaned up. Then use the granules for longer-term protection to keep them clean. And keep an eye on the plants... if you see further sign of infestation, pounce right away. Scale is awful.

Sounds good Roberta I will soak the Orchids in soapy water for 8 hours as suggested and will use granules thereafter atleast I wont have to inhale the chemicals. I agree scale is terrible I've lost lot of plants trying to treat scale.

[estación seca]

Juvenile scale forms crawl to other plants. If you have scale on many plants you must treat all of them.

[t_howell]

I wouldn’t worry about it, unless it spreads. Leaves are never perfect. Expect some normal blemishes like that.