CLOSED: Tiny white rice-grains?

A neighbor has some Euonymous that were recently infested with some kind of "blight" that I have never seen before. They turned to me for help. I've never encountered this before. Will get pix later today.

They tell me that this all occured in the last 3 weeks at most, but that may not be accurate. They only noticed the damage and presence of the insect last week.
Here's what I saw:

Very tiny chalky-white "insects" (or whatever they are), shaped like very narrow rice grains, approx. 1/16 inch long or less. On top of the foliage and covering the bark and stems all the way from top to bottom of the plant, fairly evenly distributed all over, but more clustered on the foliage like aphids do, but unless these are all dead or larval "skins", they don't move.

I brushed and pushed them with my fingers and every now and again noticed a bit of yellowish gunk (crushed insects) but not very much.

So far, all the sites I have seen are ordered by name of insect and you have to know that to check the picture.

Does anyone recognize this pest?

Can anyone point me to a visual reference for broadleaved evergreen pests?

Thanks!

Robert.

OK, I got it ID'd. Euonymous scale.

http://woodypests.cas.psu.edu/FactSheets/InsectFactSheets/html/Euonymus_Scale.html

Scroll down to the pic whose caption starts "Male Euonymous scales (white hyphens) ".

That's the one.

Robert.

And very difficult to eradicate... Euonymous are notorious for this pest.

If you can get some pictures, will you include them in BugFiles? It might help someone else in the same predicament in the future. (And yes, it is difficult to eradicate. My MIL had several Euonymus shrubs that we took down to the ground and gave up on them after several unsuccessful attempts to cut back the affecteed areas and spray the plants.)

Uh oh! We were afraid of that.

Some of the bushes have parts that are completely defoliated. I was astounded at the degree of infestation down inside the bush. Just nasty-looking.

I sprayed with "Orthenex" as I was treating azaleas and other evergreens for lacebugs and mildew. Might try some carbaryl later.

I'll be applying some horticultural oil later on.

We talked about whether the defoliated parts would come back ot not, wherther to take the lot of them out, or to just remove "dead" parts.

Sounds as though it might be prudent to remove them all to keep on top of the massive infestation.

Will make pix of the bushes for the files.

Robert. edited to make Orthene correct as Orthenex.

This message was edited Aug 28, 2006 12:08 PM

Pictures have been added to the Bugfiles.

Robert.

Orthene is systemic, so it's not necessary to add anything else to the treatment.. Still, if they were mine, I would just remove them and replace with something that is not an attractant for euonymous scale. BTW, Orthene is not a fungicide, so is not effective on mildew.

I don't know about Orthene, but imidicloprid - which is also systemic - does not work on Euonymous scales, because they are hard scales. Imidicloprid only works on soft scales like cottony cushion scales. I would think then, that perhaps orthene might also not work.

I'm going to put my work hat on here for a moment and give the advice that I give to homeowners and extension agents concerning hard scales like this - the info comes partly from my very helpful pest management handbook that I get with my job.

Scales are most vulnerable when they are in the "crawler" stage - which is the only mobile stage with hard scales that is found on the plant. This stage occurs in the spring - they will look like small pink, orange, or similarly colored aphids. This is the best time to hit them with a pesticide such as orthene, sevin, pyrethroid, etc. Once the scales settle and have their hard shell, these pesticides are much, much less effective (but might kill good bugs).

In general, the best thing to use on adult scales is horticultural oil or to a lesser extent, insecticidal soap. If the weather is warm, you'll need to use 1% (summer strength) horticultural oil. I would also suggest hitting them again with 2% (dormant strength) horticultural oil when the weather gets cool - but not cold: it shouldn't get lower than 29 degrees F if possible. Then you can see if this helps. Also hit the bushes again in the spring if you see crawlers - either with the horticultural oil again (I'd use summer strength so as not to smother the developing leaves - just in case) or with one of the materials mentioned above.

I hope that this helps some, and good luck.

ceejaytown and Night_Bloom~

I wrote the name incorrectly: I used Orthenex not Orthene. The Orthenex contains fungicide.

I used the Orthenex in hopes that it would kill any unshelled scales ("crawlers" as Night_Bloom says) if any were present and harboring a hope that it would kill any eggs. Don't know that it does that, though. And now I see it's too late.

Thanks to both of you for your help. I'm really going to advise the owners to remove the shrubs. They are just *beset* with the nasty things. Just look at the bugfile pix. ICK!!

Robert.

My experience with Euonymous scale was similar to Terrys. I had to remove 1/2 of my evergreen boxleaf Euonymous after repeated attempts to control the scale. The other half of this hedge was in more shade and the scale didn't seem to be as bad, so 10 years later these shrubs remain. They still have a little scale but they seem to tolerate them and don't look as bad as the ones I removed. I also offer some hopeful experience with armored scale that I've had. About 4 years ago we had a severe infestation of armored scale on a 40 foot Ironwood tree. No way could we spray it. The "honeydew" in the spring was like a downpour. With nothing left to loose we tried the Bayer Advanced Tree & Shrub control in early spring for 3 years. Since we started using this product the honeydew drip has been reduced by 75%. Before giving up on your Euonymous I'd give this product a try.

Thanks Lucas for the Bayer info. I'll check it out.

The owners are a bit attached to the shrubs and are willing to let the two most damaged ones go, but want to save the other two that haven't been as damaged.

Robert.