Scale on pines/junipers

Hi Nina,
It's great to be able to consult with someone with your expertise. I was a Botany major in college and have been a lifelong plant freak, but now I take care of animals for a living. Anyway, I have had an ongoing issue with scale on several of my pine and juniper bonsai. The scale itself appears to be running rampant here in SE Massachusetts. What is your prefered method of dealing with this pest. I've used dormant oil and isotox with mixed results. Thanks for any advice,

Dave

Are these the same scales on juniper and pine? Or just "generic" scales on both juniper and pine? I'm asking because using my favorite book, "Insects that feed on trees and shrubs" by Warren T. Johnson and Howard H. Lyons, I don't see any overlap between the scales on these two trees. While it's easy to give you general scale advice, there are times when a particular species of scale might be more difficult to treat than normal, due to, say, an especially waxy body, or due to acquisition of resistance to pesticides.

In general, dormant oils are effective for scale, but shouldn't be used past April, when temperatures rise. After that, you can use an insecticidal soap (I have good luck with this) or one of a number of pesticides. I'm consulting my Cornell Cooperative Extension Pest Management Guide as reference; this is a good reference for NY State, but your state has its own Cooperative Extension service, and its own webpages, online factsheets, and pamphlets. Your extension agents know what's legal to spray in your state, and exactly when to spray it, so I recommend that you get their telephone number, bookmark their webpage, and use this resource.

Doing a google search on "pine scale massachusetts", I come up with this:
http://www.umassgreeninfo.org/fact_sheets/scale_insects/pine_needle_scale.html

A search on "juniper scale massachusetts" mysteriously brings up a Pennsylvania extension site:

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

but Pennsylvania information is close enough to count. So you're all set, and you don't even need me to solve your problem! Cooperative Extension is a great thing, only it's problematic for bonsai because:

1) Some states won't give advice for bonsai because they're afraid of liability issues.

2) Most control advice doesn't take into account that you can't afford to lose branches on a bonsai; the advise "prune off diseased tissue" can be a heart-breaker.

Good luck!

Nina, thanks for the detailed response. I did those very searches just a year ago and got very little info. The links you provided were quite helpful...thanks again. Based on the information from those links, I am dealing with two separate scale species. Time for more dormant oil.

Dave

Dave:

I'm in SE Massachusetts, but I have not seen such scale on my black pines or juniper. I have often dealt with pine adelgids on my black pines, and I have used rotenone pyrethrin spray, once or twice a year, to control them.

Mike