Organic scale control

[Amel]

Soap and a bit of vinegar in warm water...does the job

Also get rid of the ants..

[Tropicaltoba]

Tropicaltoba, do you have armored scale?  While soap and hort oil kill mealybugs and spidermites well, I found that even dangerously high doses of hort oil do not reliably kill adult armored red scale.  I experimented on some infested leaves and checked them under a microscope over the next few days.  The adults were still wriggling.

Brian,
I have 2 types of armored black scale, one small which used to be a huge problem on passionfruit and citrus. Proper fertigation and spray worked well. The other is a massive black scale that I’ve only found rarely on my rose apple.

No I haven’t seen a red one yet. What dose of oil do you use? I usually use 1%. I found when the plants were loaded the sprays didn’t work, used the hosenozzel to pretreat the trees first and moved them outside and the wasps cleaned them up (no ants) and then the oil. I also alternate with a canola oil prethyrin mix. There’s days I’m usually in the trees 3x/week pollinating so I keep on top of things with my soap spray bottle.

What trees are most bothered by the reds?

[gnappi]

Guava are the only trees that I have problems with and Dormant oil and all seasons oil generally keep them down.

[brian]

Now that I pulled my trees out of the greenhouse I am happy to see ladybugs and wasps swarming them, eating scale insects.

Tropicaltoba, I don't know exactly that percentage I am using, but I normally only spray hort oil on foliage at the lowest recommended rate on the directions sheet.  I use much higher rates if spraying only leafless limbs. 

In this particular test, though, I just keep doubling the dosage and spraying again every couple days to see if it would kill the armored scale adults through their shield.  I got to the point where the trees were shiny all over, causing leaf damage to some and outright killing one.  These were trees I was planning to get rid of anyway so I don't mind experimenting on them.  But, even at these application rates I still saw adult armor scale wriggling through their semi-transparent shell.   

I finally tried sythetic insecticide dinotefuran which killed them, but it is expensive.

[Tropicaltoba]

Brian, if the tree is dense with scale a single spray doesn’t work for me. That’s why I blast first with  a hose if it’s bad (hasn’t been in a while) and then use the 1%. When I spray everything gets covered, I spray in the evening or when I know it’s cloudy all day and I have had no issues with toxicity to the plants.

I think millet has lots of experience with this, I followed his advice.

[brian]

I end up hose-blasting every single leaf top and bottom one by one.      Even if using insecticides... because with the armored scale it is hard to tell if they are alive at a glance, so it is difficult to tell if an infestation is spreading or if you are just seeing dead ones. 

I think if I was really diligent about spraying hort oil every week or two for a while at usual safe rates it would work, but I can't always find time for it and the reproduction cycles continue. 

[Nick C]

I ended up taking that soursop in the picture outside today. Cut off and bagged all the foliage. Then sprayed off all the scale on the branches. Somehow they’ll be back lol

[Tropheus76]

This is the first year in the 14 I have been here that I have seen them, I have these bright pink volcano looking scale bugs about the size of a pencil eraser that infest the stems and trunks of various trees. So far I have found them extensively on figs, some on Florida red maple, weirdly on a single branch of Mountain Annona(but very heavy on that lone branch). They were being farmed by these big red ants. I sprayed all of the trees and oversprayed everything else in close proximity with a hort spray that said it was designed for scale(couldnt tell you what it was) after physically removing them. I have only seen a couple since on the figs that I figure I just missed on my first go round. The ants went elsewhere.

[roblack]

this gal!

[Tropicaltoba]

Yeah I found ones like that on my rose apple a couple of months ago. They don’t seem to be too aggressive yet.

[brian]

Roblack the ladybugs on my trees right look just like your photo.  I guess this is an immature instar stage?  I know in my area they are orange as adults.

EDIT - it seems there are a bunch of black ladybug types, and these are adults. 

[Tropicaltoba]

Brian, lol I didn’t have my glasses on I thought that was a scale. There is a similar native one called a “twice stabbed” lady beetle that does is red scale and other pests . I collected a bunch of these a few years ago off my infested citrus when I used to take them outside. I was unsuccessful in keeping a population in my tiny gh over winter.

There is a lot of work going on with “integrated pest management” and agriculture (both indoors and out). It can be a bit of a rabbit hole once you start doing some reading. It’s based off sound experimental science, but starts to get a little pseudo-scientific when people apply it in practice.

It may be worthwhile to look at developing a insecticide free native habitat around your greenhouse so that during the summer native beneficial insects like the “twice stabbed” can help keep pests under control during the peak growing months. Spot treatments with oil and soap are still ok, but you may want to be selective with systemics.

[brian]

I tried purchasing ladybugs and specifically mealybug destroyers a few times over the years, and I stopped all chemical control well in advance of trying it.  In all cases except one they simply died or disappeared quickly without doing much.  Once I saw larvae of a new generation of mealybug destroyers but not very many and they quickly disappeared also.  I don't think keeping a stable population of non-native bugs is very viable in a small greenhouse, I guess it would be like trying to keep bees inside one.  Even in the short term they didn't make any noticeable impact on the scale population despite me seeing them eat a few.  And they are really expensive.  I wish I could make it work but it just doesn't seem possible for me.

[Tropheus76]

It would appear that I have something called Fig Wax Scale - Ceroplastes rusci. Primaryily goes after figs but as I said, it appears that it likes a few other odds and ends as well and doesnt just sit on leaves. Looks like from what I have read, they are only in Florida in the US.

[brian]

I just looked up fig wax scale.  They are pretty cute looking as far as bugs go.  Too bad they are pests instead of predators