Tues, one way to tell if they're dead is the shell becomes hollow.
Can you set your hose on high stream and try knocking them off? I'd do that on a daily basis w/o getting the soil wet.
I don't know how often you can apply the oil..I've been using Fish Emulsion, but because it's a fertilizer it can only be used one a month.
You don't want to clog pores, but if your plant is as infeseted as you say, clogging pores are the least of your worries..Perhaps you should do it once a wk..But I'd first hose w/water, try knocking those suckers off. Toni

Here is a link that might be useful: RE: Scale and oils - frequency? How to tell if effective?

Toni, Thanks for the hint -- I guess I'm not sure what hollow looks like.... If I squish a live one should goo come out? (sorry, I know this is sort of gross.) So far, when I've pinched/thumbnailed off any of the scale, I haven't seen any gooey stuff at all. That's part of what is confusing me. Even on the leaves that are yellowing with the attack, when I peel off the scale on the undersides, there seems to be no indication of "live animal fluid" in what I'm scraping off. That's why I'm having a hard time telling if what's on the tree is alive or dead.

I'd really like to do another oil application but I'm afraid of just smothering the tree. Some folks mentioned massive leaf drop if you overdo it -- I'm not sure my tree has enough leaves to survive a massive leaf drop --although as of last night it seems to have set some 15 buds for blossom. Don't know if its just delerious or what.

Tues, what I mean by hollow, oh boy this is difficult..lol..the shell looks empty. If you were to smash a live one, you'd need to apply some strenght..A dead scale falls off the tree if you blow on it.
I had a problem w/scale this winter and used this remedy..2-4 drops of dish soap, garlic, ground citrus and 1 capful of Fish Emulsion. This is a preventative more than an insecticide (to scale) But after I applied two times, (the FE is only used once) I noticed many dead scale..they're just empty shells. I added all the ingredients to a mister and sprayed thoroughly. I actually did this 3 times and no new scale have been found..I also plucked a good number and swiped the area w/rubbing alchol.
I don't blame you for not wanting to use too much oil..there have been several posts here from ppl who used oil and their plants' leaves dried up. So be careful when using.
This must be a bad yr for scale bug. I've seen too many posts and talked to ppl who are battling them. I haven't seen a scale bug on my plants in over 10 yrs, now suddenly they appear. Something is fishy. Keep us posted how everything works out..Toni

I grow lots of plants indoors and scales are a big problem fo rme in the winter,when plants are stressed form lower light and less than ideal temp/humidity.I've tried soem of everything and have to be very carful,b/c I have my plants in an animal enclosure.Insecticidal soaps and other such ''safe'' alternatives to pesticides are useless for stopping the adult scale and constant application is not an option in my case.Using a toothe brush and dish soap to scrub them off works to slow them down for a few weeks,but never eliminates them.I usually control them as best I can with manual removal unilt temps are warm and then I take them outdoors and spray them once a week with Malathion(at Home Depot in a grey and green bottle).After a few applications(3-4) and manual grooming,I eliminate them pretty well.I hose the plant down after the spray is on there overnight.I can't use anything sytemic or any oil that would leave a lasting, toxic residue.I would avoid sytemics with plants you are eating fruit from.With any pesticide,apply it on plants that are not in any direct sun,oils and wet applicates are especially harmful,when the sun is shining on the coated leaves.I think this may have contributed to some of the leaf drop/burn people are experiencing.Scale are most probably going to heavily infest only very stressed plants.Not to say that any plant can't be suceptible,especially when indoors,in close quarters with other plants.Stresses plants are the ones that suffer though.The Malathion has worked for me on several types of scale and I follow the label directions, which include directions for treating scale and citrus.Hopw this helps and good luck...scale are real pains to get rid of.

I had a terrible experience using Malathion. About 10 yrs ago I inherited a gardenia tree that was infested w/scale. Instead of using my own insecticide brew, I decided to get the Malathion. I followed directions to a T. The following day every leaf yellowed, dried out and the tree died..I dumped that stuff fast.

So, be careful when using harsh chemicals..and if u have kids/pets, beware..that stuff is poison and very toxic.
As it was the tree was outside, in the shade when I used it.

I'll never use it again. From now on, it's my own solution, that is safe and effective. This winter was the first time my citrus got scale after bringing in an infective Olive tree. I didn't know it had scale otherwise it never would have been set in my gh..the citrus growing in the house were bug free. Thank God.
After discovering the scale, I went outside w/my mister filled w/1 capful of Fish Emulsion, 2-4 drops dish soap,garlic, citrus rind in a mister..after 3 appliations, all scale were dead. (by the way you only use the FE once) but other stuff can be used at least 3 times. Toni

Toni, Thanks so much for the expanded description of dead vs. live things. Its just that they are so little and so non-scurrying that they just seem inscrutable to me.

I'm thinking that my first oil application was simply wayyy underdone in terms of spray/saturate (amount sparyed on) and concentration (oil to water ratio), because there seemed to be no lessening of their appearances and I just couldn't tell if they were leftover corpses or new bugs in many cases.

Unfortuanately for the quick kill stuff, I flatout cannot use any broad-spectrum insecticides like Malathion -- not only do I have aged pets (one of whom sleeps in the 30- gal pot this tree lives in) but we are in an all out "beneficials vs. pests" war here with several other pests and I and my neighbors have been working too hard to create a beneficials-friendly environment to risk it with a powerful and lasting insecticide. I've got to stick with very localized, contact treatments (this is an outdoor pot). I would be willing to use a soil soak like imidacloparid, but am leaving that for a "last ditch" (though we may be rapidly appraching this with only about 15 leaves...), but the tree has just put out about 20 new leaf buds and has about 11 blossom clusters (in spite of its debilitated state).

Does anyone have any advice on my third question? Can armored-up and sedentary scale reattach if they've been knocked down/off by scraping?

Thanks for all the input!

Tues, that's a darn good question..I've read in many posts that hosing the plant will detach..but where do they go after that? Do they find their way back on the tree?
Like you, I have pets and don't like messing w/strong chemicals..I only use natural products around the house. I have birds, a dog, and birds will die if he/she lands on a plant sprayed w/harsh chemicals.

I think scale are like armored batlled warriors..LOL..The only suggestion I have is to hose the plant, aiming away from other trees. I go over scale infested plants w/a fine tooth comb..I chcck each leaf, under and over, pluc w/finger and thum, then crush..then I swipe each area w/rubbing alcohol..this seems to have done the trick.

Also, I talk to a woman who owns a nursery in Fl. she gave me the best advice, something her family has been doing since the 60's. She uses a capful of Fish Emulsion and sprays leaves as a preventative..I found this to work fantatic..I don't know if you can use this product cause of your pets, but then again's it's natural..I also added, (to my mister) 2-4 drops of dish soap, garlic, and citrus rind..and sprayed away. My citrus were bug free until I brought in a badly infested olive tree..The plants next to this tree caught the scale..but I've been using my brew and so far all the scale have died. I wish you luck..Toni

huh...... fish emulsion.....

OK, I tried the canola and Volck again yesterday, since we haven't seen the sun here in a week, I don't think I have to worry about burning issues (The weather girl on some channel here announced in a depressed tone last week, "We'll see the sun again in July." and that's surely what it looks like --- a major coastal inversion to fog us for the next month.

I'm thinking I'll try a repeat in 2 weeks, this time with the fish emulsion/garlic/etc.

Hopeful author -- what are your relative ratios? E.g. is your mister a 1 qt job? Citrus rind -- one lemon? Two oranges?, garlic (one clove, two?) Thanks for your recipe in advance. I really want these things gone!!

Tues, you can call me Toni..(S)
The problem is I don't really measure anymore..It's like cooking a dinner, after you prepare a meal often enough, you do it by feel.
Not that I have many problems w/bugs..I use this brew as a preventative, too..
1 16oz plastic mister. 1-2 cloves of finely crushed garlic, or you can boil the garlic, cool water, then add this water to the mister..A wedge of citrus, (not 1 or 2) LOL, say 1/8th wedge..any type will do..either grapefruit or lemon preferably. Something bitter compared to sweet. I grind the rind and add to mix plus been squeezing the jince in water. 2-4 drops of dish soap. 1 capful of fish emulsion..(btw, only use the fish emulsion once a month) Anyway, I mix together, shake mister, then spray thoroughly. If you do this once a month or every other month you should be bug free..Good luck, Toni

Malathion is strong stuff and is not my first choice and I can even add that it appears inaffective to a small scale type that is tan/red in color and very dense in population,having no squishy innards to indicate life.They are flat and dry,overlapping and cause severe discoloration to leaves.I have them attacking an apidestra and rhapsis palms.I have tried everything to eliminate them,but they just come back,even afer repeated applications of everything under the sun as well as cutting the apidestra down to the ground.The Malathion did work very well on traditional scale and succeeded where other,less toxic remedies failed.I did have to use it a few times and as these plants will be used in my chameleon enclosures,I did not want this to be my first choice.It is not systemic and with a few good rinsings in warm/soapy water and a week or so outside to air out,I would expect it to be safe.I reiterate what Toni said about it harming the gardenias.Some plants do have a marked sensitivity to it.It has burned or blanched some leaves on the rhapsis palms and a draceana,but these will regrow to cover the damage.Scales are most prolific on stressed trees and plants,keeping plants in the best possible conditions, should help to avoid the scale.Adult scale do not find their way back tot he tree, if knocked or scraped off.Even if they did,scraping them off usually breaks the proboscis they feed with an dthey would starve.The adults are more or less something to wait out,the crawlers(moblile stage of the scale) is what you are really after with spraying and that is why reapplication is needed.The adults die off on their own in a while,if you can kill the new generation before they take hold,you are winning the battle.I HATE SCALE!!!

I wouldn't use Malathion on any plant, moreso if I'm planning on eating from it.
There's natural ways to rid scale, including plucking.
In my opinion, one reason ppl are dying from cancers these days is because all the stuff they use on produce and meats. Toni

Toni, thanks for your recipe. Yep, I do know about that "cook up the batch thing" once its part of your daily life -- thanks for breaking it down into passable-on lumps!! I'll try your recipe on my next drenching... a week or so from now.

Just as a followup. I had indeed tried the Volck/Canola assault again (before Toni's neophyte translated recipe), and this time did something very important, I think: I shook the container every three or four squirts. VERRRRY different appearance of plant and very different effect on various fauna. After this application, I can now see "dead ones" --THANK YOU Toni--- yes, now I'm seeing "hollow" things -- I think my previous oil application lacked enough shaking to re-emulsify the contents such that it pretty well left most of them untouched and happy, merely drenched in water. The shaking of the container resulted in a plant that was clearly "oiled" and 6 days later had a whole slew of scale that were clearly "hollow" -- dry and fell off at the slightest touch. Wayyy different than my previous experiences. Aha! Now I see!

OK...... you'd think I'd be happy and done now..... but now I have a followup question----- My tree now has an oil coating that I'm noticing a wide variety of flittery insects (aphids, various gnats, etc.) stuck to the oil on the leaves. Should I now rinse the plant to lift the coating? Is the coating suffocating it? (What a newbie!!!!! What can I say???) Thanks for words of wisdom!
Tuesday

I am wondering the same thing but probably for a different scale that is on Rose bushes. Once the scale is dead is it necessary to scrape them off? It almost seems like they are on 1/16" thick. I had to take an infected cane to a nursery for them to diagnose as I had thought it was some kind of bark disease. When she said scale I thought that scale affected leaves but these scale were only on the bark and so think the canes appeared sickly brown/grey. I sprayed with NEEM oil a few times but like Tuesday mentioned I haven't seen dead scale. Do I need to scrape off most of the scale before spraying? I read about a toothbrush and alcohol, is that necessary?

looks like a dormant post... Any help would be appreciated.

When I have a scale infestation I see more on the stems than the leaves. I scrape all of them off, live and dead. The dead ones seem almost papery and the live ones are harder. I check the plants daily and remove whatever I see. I've tried fish emulsion and insecticidal soap with zero results. Wiping the plant down with alcohol soaked cotton balls seems to help the most and I had some luck with horticultural oil. I only have problems when my plants are being over-wintered inside. During the growing season outside I spray them with a hose frequently and never see any bugs.