Croton Scale - what's working?


Well-Known Member
First, some observations...

1. For three years I stopped fertilizing the garden. Everyone around me had Croton scale; I had none. This year, I threw down a bag of fertilizer, don't ask why. Now, I have Croton scale on dozens of plants.
2. There doesn't seem to be any rhyme or reason to what's attacked. Even the same variety in different parts of the garden. I have Victoria Gold Bells in three different locations, only one has scale. My Ethel Craig is covered with scale, but only one of the eight Crotons next to it are affected.
3. It's fast. Very fast. Within a week, I'll see a healthy plant get covered with scale.
4. Color, leaf-shape and size, lighting conditions, all have nothing in common with whether or not a plant will be hit.

Okay, what's working...

1. Clippers. Yep, I'm hacking plants back to the branches, cutting off every leaf and letting the plant start over.
2. Poison. I'm using a mix of Organicide and Malathion at the recommend dosage and spraying the affected plants until they are drenched. Repeat every week or two. This seems to kill everything but the plant. The plants I clip back are getting drenched after the clipping.
3. Not yet thinking about replacing the Crotons with another plant, not another Croton, but that time will come.
I have been using Bayer 3 in 1 which works for a few months, until the systemic part of the treatment wears off. I have started using Terro ant poison, drops and piles anywhere I see ants, because they are transporting the scale onto the crotons. I also trim low branches that touch the ground. There is improvement but haven't licked 'em completely. The problem I have is that I'm not always there to keep after it.
I saw a bit of scale (type unknown) on one scraggly Cousin Itz that went in the ground about a month ago. It got blasted with coffee, a touch of Bayer 3:1, and a bit of Ortho general purpose. No more scale. This particular croton patch is getting all the coffee grounds for a while as a prophylaxis.

See the IFAS paper for other plants affected by croton scale.

Koki - interesting you should mention ants. I've never seen so many ants in the 25 years I've been here. They are in almost every air layer and are running amok throughout the yard. At least they do not bite like the (*&^%$#@! fire ants.
Google ifas edis + croton scale for starters. It will take me a while to dig out my hard copy of the paper I'm thinking of.

I'm better organized than I thought - sometimes. For more info than you'd ever want to know about croton scale see:
Florida Entomologist 93(1) March 2010
BY Gregory S. Hodges and Christopher J. Hodgson

It's 15 pages long. My print copy does not have a URL and I do not recall where I got it. But the IFAS website has tons of good info on it even if some of it takes a bit of searching.

A shorter paper is the PEST ALERT,
Koki - interesting you should mention ants. I've never seen so many ants in the 25 years I've been here. They are in almost every air layer and are running amok throughout the yard. At least they do not bite like the (*&^%$#@! fire ants.

It's one of the bad things about a very warm winter
The following is taken from a letter by Alastair MacLeod dtd 28 Jul 2008:
"The movement of these juveniles or "crawlers" is via air movement and a silk-like filimentateous strand attached to the young scale.
So how deo we stop a fast moving, airborne pest that multiplies when sprayed with contact insecticides?"

I would say that the ants are symptom of the scale - if it is the true croton scale, Phalacroccus howertoni. Other scales can infect or infest crotons - but not the way this bugger does, and ants are frequently in the company of other scales. But this bugger is easily spread by air movement - and the wind can blow a lot faster than some ants can travel.

For anyone concerned about this pest, your best bet is to educate yourself by reading as much as you can.
OK, crotonheads - time to educate ouselves even more. Do yourselves a BIG favor and Google croton scale. The second hit is one titled:
[pdf] Another New Scale in Florida with a rather lengthy URL

Lots of color pictures and lots of great info on this pest and other that look a bit like it. I've saved a copy and am gonna print me a copy as soon as I finish this. Good reading during lunch...
Here's a few pics of the scale on a leaf of Cousin Itz. The scale got a dose of the mix described in a post above yesterday. Pics taken with a Nikon COOLPIX 2100. No special lens was used. Even looking at the scale through a 15x magnifier I use for philatelic work, I have no idea what kind of scale it is. Whatever it is, it is the only croton in the yard with it. The only other scale in the yard is on the bamboos; this scale is tended by ants and also kept somewhat in control by the resident lady bugs and has been here for several years.


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Nkow here's a few pics of what I think is the true croton scale. Found it today on one small plant. With any luck, the little buggers are in their death throws as I key this in after a coffee and Orthene spray.


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If I were you, I would cut the top out of that plant and bag it up and spray the heck out of the whole yard. I know its a matter of time before we have it here, but try to delay it as long as possible. Everything I bring in from the east coast goes into the garage until I spray it about 5 times.
hmmmm, a post got lost but in response to Ray's post:
The little buggers got some fresh brewed cold coffee diluted 50% with tap water and a dab of Ortho systemic around noon.
This evening after running my irrigation system (on my appointed day), I sprayed the infected area with the coffee & Ortho solution plus a dash of Bayer 3:1.

I hate to resort to drastic methods if something else will work. Like thinking! Take a close look at the two posted pics of the light green scale on the stem; now blow them up. Note the nice uniform green color! Compare these to the pics in the paper referenced above. They sure look a lot more like the Philphedra tuberculosa pictured. If anything is alive tomorrow, I'll try and get some real close up pics. So for tonight, the mystery green scale can suck up all the caffeine and synthetic nicotine it can under a full moon and die quickly...
I hope...
Here's two better pics of the scale taken this morning. Not the )(*&^%$#@!~ croton scale but Philephedra tuberculosa due to the uniform green color.
Whew - kinda like getting a false positive on your Wasserman test!


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I am going to have to agree with Keith,i would cut off the branch.This is the scale that is all over my garden,It is debilitating to my plants.It might not be "croton scale" but it is certainly going to cause decline in your plants.All those scale insects sucking nutrients is going to leave your plants weak and anemic.What is interesting is that even though this has been here for years there seem to be no insects eating them yet.The scale can be treated but it is a major pain in the ass.i would watch all plants close by also as they have probably migrated to neighbors.All you growers up north will eventually get the scale but i would try and delay its spread as along as possible.

Here's two better pics of the scale taken this morning. Not the )(*&^%$#@!~ croton scale but Philephedra tuberculosa due to the uniform green color.
Whew - kinda like getting a false positive on your Wasserman test!
Merit,also known as " imidacloprid".It is sold in Home Depot as a Bayer systemic in granules ($25-30 for 4lbs).If you want to buy it bulk it sells for $55.00 for a 30 lb bag.I used to buy it a Home depot but it is much cheaper bulk.Hopefully you only need a small application so HD should be fine.I found that the 4lb pack treats around 50-70 3g plants but the bigger the plant the more you will need .The Bayer brand found in HD is better in my opinion to the bulk product (it works faster and does not leave a goey sludge left over like the bulk product) but I got tired of going to HD to buy this.

Mike -
What have you been using to treat your scale?
What is interesting about the scale is that the plants sometimes lose all their color and just go to solid green in really bad infestations.I have a Glorioso that was hidden under my big Sago.I never really pay attention to it and around 2 months ago it was 100% covered in scale.It was treated but it is now solid green with absolutely no red.

Mike -
What have you been using to treat your scale?
I checked all my Crotons real good for scale today and I'm happy to report no scale was found. I have only delt with scale once on a Croton. That plant (from S Fl) was purchased at one of the Society auctions last year and was found within 2 weeks of acquiring. I treated with Bayers 3n1 and Orthene. I quarantine all new acquired plants for around 60 days.
I had a few large plants with a heavy infestation. I cut off all the branches with scale and then treated with Merit. Wanted to get the scale out of the garden before it transfered to neighboring plants.Couldn't wait for the merit to travel so far up the plant to become effective. Growing season is really kicking in, the trimmed plants should be fine by winter.
Those in the pic got a dose of Crisco canola oil spray to smother them for good today. Pam, WD40, or almost any oil would work for a very limited infestation such as this.