Plants that tend to be sensitive to oils.

Black walnut
Cryptomeria
Douglas-fir
Hickories
Junipers and cedars
Maples (particularly Japanese and red maple)
Redbud
Smoke tree
Spruce (particularly dwarf Alberta spruce)

Jon

I'll take that as a No. Thanks Jon.

The only thing I think is certain is that glaucous, ie. "blue"varieties can be made green by such oil application. The oil readily dissolves the waxy material responsible for the glaucousness.

+oM

all that said./. proper IPM ... integrated pest management.. would suggest you spray NOTHING without ID'ing an actual pest ...

besides the fact.. doenst oil work thru suffocation ... hence.. spraying it prophylactically .. would not really accomplish anything ....

which leads to the question.. are there mites on the plants NOW ... or did they all die for winter ... in my z5 MI.. mites are long gone... i dont know about your z7 ... so it would be a waste of oil.. my time ... and some might suggest.. its just polluting ....

as that beer ad says.. sorta.. lol: spray wisely my friend ...

ken

ps: never heard of using sulfur on conifers ... but i dont have time to research such.. what is the point of sulfur on the other plants ....

Fungicide. And in actuality, hort. oils are ideally suited to prophylactic care. That being said, yes, of course a target insect and/or mite must be present in order to justify the spraying of any material. Sometimes, the primary stuff gets taken for granted within such convos.

Finally, mite/insect eggs can be suffocated by oils, although very light hort. oils may not be the best choice for that. Methylated veg. oil, for instance, is the first choice in suffocating gypsy moth egg masses.

+oM

mites can also be taken care of.. in the ordinary backyard with a stream of water ... why in the world would you need anything else ... just because you have it????

i am a bit confused .. just BSing here ... i would never argue with +om on tree stuff ... how an oil works.. prophylactically .... i was assuming the egg part ... which is technically prophyc. for the adult ...

but i dont understand how covering a branch .. lets say ... with oil would stop some bug in a few months from now, when winter passes ...

sulphur for fungicide.. i should have remembered that from my rose growing 20 or 30 years ago ...

you know.. back in the day ... first house.. single.. money for any whim.. mom's name rose .. family heritage of having roses since i was a kid.. got a little carried away.. and started collecting hybrid T's .... i was quite the chemical warrior ... spraying and fert'ing them every 4 to 6 weeks.. i still have a bin of all the chems .... get married.. moved.. roses dont grow in sand, so that collection was terminated ... and i decided .. with the kids.. to go spray free ... and you know what... spraying things is a waste of time.. money.. effort.. and an affront to your health ...

plagues come and go.. and frankly.. little if anything dies if you simply dont spray ... frankly ... its the most organic method..

and if things get too ugly.. or do in fact die.. so be it.. it is an opportunity to get something that isnt inherently sickly .... why struggle with carp plants ...

OP ought to wonder.. why his/her ' Dogwood, Hepticodium and other trees a couple weeks ago with sulpher and oil' need so much care???

have fun no matter what you do ... after all.. it is your garden .. and be safe ... but think about why you need be doing this.. and why you are thinking about expanding your spraying to include other things ...

ken

I only use oil for scale on my pines sprayed in April by a certified Arborist.

Nothing else is sprayed with oil.

As mentioned above any blue, blue/green cultivars hit with over spray will loose color back to green..

As far as I know oil is never sprayed for mites. As Ken says hose spray them. Of course there are chemicals for mite eradication but in most cases not necessary.

When in doubt always ask your county extension agent or and expert tree Arborist before spraying chemicals in the yard.

Dave

This post was edited by Davesconifers on Tue, Dec 3, 13 at 8:56

From what I "recall" sulpher is to be used when the tree is dormant in early spring or anytime it has leaves non dormant leaves.

It must be a climate dependent thing but no amount of spraying with water will get rid of mites here. They just multiply too fast I have found. The best thing I have found is to just forget anything that consistantly gets infested- except for the citrus. If I spray with oil once or twice in the cool of spring then I won't have a problem all summer. Oil is more benign than most of the "organic" pesticides and it works very well.

In the main, I agree with you, Ken, on the basic principle of spraying as little as possible. My own lawn, for instance, could not be lower input. I didn't even apply any fertilizer this past year. It's an old and established lawn, so just the growing and subsequent dying of root systems is enough to supply the soil with renewed essential elements.

I think that oils can indeed be a part of a mite control program. Obviously as with any pest control regimen, timing is critical. So there too, if the target organism is not present, and your control product is a "contact" material with no residual action, then no, it makes no sense to apply at that time. And traditional chemical miticides have tended to be some pretty toxic materials, so anything short of that is a good thing in my view. But again, it just depends on all the other factors-value of plant(s), purpose for growing them, ie, to sell, well, you can't sell plants with mites on them to folks, area of country, and therefor, species of mites present, threshold issues, as in, can you tolerate some damage, or can you not? The list goes on. All we can do is provide information. How and why it gets used is in other hands.

+oM

I rarely use any kind of insecticides, opting more for old fashioned / mechanical means. Spider mites for me have been easily controlled and even eliminated with the use of a strong hosing off. Sometimes I need to do it a couple times but it has always worked. Usually those are only a problem on my tropicals / palms that I bring in for the winter. I control with misting, then on a few warm days throughout the winter I will take them out and hose them off good.

One of my conifers, a Pinus Sylvestris 'Gold Coin' has a significant scale infestation, and thus I used a dormant / hort oil on it. I will likely need to do this again in spring, and possibly treat it with a systemic as well as it is a fairly heavy infestation.

The scale did unfortunately spread to my Pinus Strobus 'Elf', but only on a couple of branches. I used this same hort oil treatment on the bottom 2/3 of the small tree and so far it appears to have taken care of the problem. I'll know more in spring. While the tree itself is fine, and the problem appears to be taken care of I now have a two toned plant. Bottom 2/3 is regular green from the oil, while the top unsprayed part is still the nice bright blue / blue green. I'm hoping that I can get this issue taken care of fully before any new growth at least the new growth will stay the nice blue color. I knew this was going to happen, and while I'm not thrilled with it, I want the plant to live and be healthy. Id rather sacrifice some color now for a healthy plant, than let it go and be dealing with a larger problem later that could possibly severely harm or kill it. It will recover its color in time. Here is a photo of it post spraying with oil:

Unfortunately the sprayed part that now is green will never revert back to original color. New growth will be green/blue.

In time as the plant grows it will cover that part up.

Something that small just take your fingernail and peel the scale off if not heavily infested.

Dave