Palmetto scale problem

[mnorell]

A friend here in Natchez installed a dozen hurricane-cut Sabal palmetto in May 2008. These have now finished their second season of growth and have put on 10-14 leaves in each crown and have an overall good appearance. Unfortunately they appear to have varying levels of scale. A few of the palms are severely stressed, absolutely covered in scale, and the emerging foliage is largely destroyed and dessicated. I'm assuming this is Palmetto Scale, Comstockiella sabalis. According to the UF info sheet on this pest, they should exist at low levels due to the presence of naturally occurring parasitoids. I'm wondering if the parasitoid may not exist in this part of the south, though Sabal minor is native here and I don't recall ever seeing any stressed by scale. Perhaps the scale have just gotten out of control due to the palms being stressed during reestablishment.

I'd like to recommend a safe method of destroying these pests before more significant damage is done, hopefully something avoiding commercial insecticides. I'm guessing a soap or horticultural oil treatment would effectively smother the beasts? To prevent them in the future, does anyone know whether Tom Broome's coffee-grounds mulch-treatment (which he has successfully used to destroy Asian Cycad Scale) would be effective on the crawling stage of this scale..thanks in advance for any help with this!

Photos of the situation:

Overall installation (the healthiest portion):

Damage on the worst-affected specimens:

Closeup of the scale:

[www.dadluvsu.com]

If you don't wanna go all nuclear warfare with chemicals to destory these pest, I say, washem off as best you can, load those puppies up with safer soap, neem oil, whatever... Then liberally pour on lbs. of coffee grounds. Me personally, if it was that bad, I'd at least zap em' with some pro strength chemicals once to get things manageable. Then go for the coffee leftovers. I wonder if you could just pour room temp coffee directly on em' to knock em back? Espresso anyone?

[JLeVert]

I've had good luck using Bayer insecticide with imidocloprid. It is systemic and gets the scale under control. Volck oil in the winter is also good. I have found that after the palms are really established, they are less likely to have scale if they are in full sun and are well watered.

[FRITO]

Malathion horticultural oil works for me.

African Iris, Chamaerops humilis, Butia caitata all had scale and have since eliminated it with 2 treatments. the second treatment was sprayed with a ahand spray bottle 2 weeks after the second treatment. A 3rd treatment will be needed in extreme inferestations.

the oil is mixed with water and sprayed on every inch of the leaf and palm which scale resides.

it is good to use horticultural oil to fight scale in fall and winter as the heat and sun are not strong and wont burn the foilage, some of which I experienced in 90 degree temps.

never seen scale like that before on mature palmetto, must have been stored with other infested palms in less than ideal conditions before being planted out.

[www.dadluvsu.com]

I was thinking about this last night and remembered ladybugs.... You could order a huge number of ladybugs and thaw them on the scale. Ladybugs lift the scale's shield and eat the critter underneath. Just an idea...

[Kris]

Nice topic,i have not see them in palms yet but all our hibiscus plants were infected and they are dead..i meant our hibiscus ? And we stopped growing these plants and our garden has no problem now.

kris.

[mnorell]

Thanks everyone so much for your help and suggestions!