I prefer heavier oils, I have seen no studies but my reasoning is these mineral oils that evaporate within minutes have less a chance of completely smothering things.
The Stollers is a soybean oil. I looked around and it seems it is a wholesale thing only in the US these days…
Here is a canola one:
This outfit, Arbico, I have ordered many times from and always got what I asked for.
I just got their catalog on my mailbox today. Thanks for the helpful information.
Re: Spinosad. My understanding is that with the commercial formulation, Entrust, the only difference in the concentration from Monterey or Captain Jack’s which we can get more easily.
As long as the buds are not open it is not too late.
They are swelling a bit though. Whether or not they’ll survive to bloom and fruit, notwithstanding, of course, since it’s only early February.
I guess I’ll do my early spray this week. it’s cold and things aren’t quite pushing yet. this thread helps a ton
I don’t believe knowledgeable orchardists say you have to use oil of any kind if you don’t have known scale or mite problems… or psyla in your pears.
Can anyone explain to me the logic in using a canola based oil over a petroleum based product? Is the point to reduce carbon footprint? I burn almost 20 gallons of gasoline every week just to get from one orchard to another that I manage. When there is enough green energy to supply all the electricity we use I will buy an electric truck… if I’m still alive and in need of a truck. Still, I guess every drop in reduction helps… how much petroleum is used in the production of canola oil? If it isn’t used for food, how much more land needs to be used to produce the greater need for canola oil?
Aphids too, right?
Around here, usually lady beetles are the best cure for aphids and certainly an early oil spray does not stop them from showing up a week after you spray. I only think of aphids as a problem for young trees I’m trying to establish or size up as soon as possible, and for them I sometimes will work to control them, but only after vegetative buds are well into development with small leaves formed and aphids are apparent.
Here leaf hoppers are a much more difficult issue than aphids in stopping new vegetative growth and I do not rely on oil to stop them. Both of these are problems that show up well after bloom.
I sometimes wonder how much leaf hoppers affect established apple trees in terms of carbohydrate reserves. An awful lot of energy is being sucked out of infested trees that might affect a trees ability to bear crops the following year.
They reduce the growth of annual shoots a great deal, so lots of that energy is being used for unwanted new shoots, but some may be shuttled to other parts of the tree, including the buds that will produce next year’s flowers and ultimately fruit. Also, to the roots, which can store a lot of starch for later use… probably including for fruit production in its spring stages.
My own logic is mineral spray oils these days are all very light and evaporate in almost no time. I like a heavier oil which will be on the bark longer.
I spray oil mainly for peach scale these days, also San Jose scale is sometimes around. Since it’s in the tank everything gets oil including things that may not need it.
Yeah, it’s strange how peach scale has recently become so pervasive here. Until 4 years ago, I had never seen it. It can kill a tree pretty quickly if untreated… well, by quickly i mean maybe in the course of a whole season. That seems to me to be particularly lethal for scale.
I would think that if a heavier oil is more affective in smothering pests, it would be mentioned in guidelines. It seems like a pretty fundamental thing to overlook, but it’s certainly possible it has been.
I found mention of heavier oil for dormant spraying in old fruit books. My personal theory is it was one of the many bits of knowledge that got lost along the way. When lighter oils came along everyone got excited about how only one oil was needed to be stocked.
I’m not sure the commercial industry functions that way and San Jose scale is a huge problem for commercial growers around here, so if the heavy stuff worked better it seems like it would be known, at least for that pest.
It could be growers switched to primarily relying on poisons for San Jose scale.
Here is a quote I just found from a 1950s Canadian spray guide:
Again, in dormant spraying, a mixture of two gallons of heavy dormant oil and four gallons of lime-sulphur per 100 gallons of spray liquid was recommended in high-volume spraying against the San Jose scale,
So at one point they were recommending heavy oil. There could be some reason for the switch to lighter oils for dormant spraying but I never found any details as to why.
Of course heavy dormant oil was recommended when that’s all that was available. Cornell never stopped including oil as a recommendation as one means of controlling San Jose Scale. In a 2010 commercial guide I’m looking at, oil is the only material they recommend for treating mites. In the same book they speak of the difference in oil formulations but it is only about potential phytotoxicity and not efficacy.
Nevertheless, you are right that for treating SJS the emphasis seems to be on synthetic poisons although they include oil as an option. I was unable to find research that evaluated the efficacy of any kind of oil for SJS.
Over the years I have often successfully treated SJS with hort-oil but peach scale freaked me out and I decided to treat it with a combination of oil and Centaur. Knocks it out every time with likely no return.
Hi Scott,
Thank you for all you do for me and the group!
I checked out the Tritek oil which you reccomend. Looks like good stuff which I will get in the future when my trees get bigger, and I need more.
Right now though I have some Neem Oil. Would this be more beneficial to use in my Horticultural Oil recipe that I make up, than just Canola oil, or corn Oil, etc?
I am doing my Green Tip to Pink spraying now, and why I am asking.
Thanks John
For dormant spray any oil works pretty well so if you have neem I would just use it.
Great, thanks for letting me know!
John
One more question regarding Green Tip to Pink spraying.
Our days here in Kentuckyk were getting warmer, but then like much of the country we had a set back with colder days and nights again with temps around or just below freezing at night. Day time temps this week in the 40’s and low 50’s. Maybe in one more week getting into the 50’s and some 60’s.
So, I wonder, about the bugs being less active, and the effectivness of doing my spraying now or whether it would be better to wait a week? Asuming that my trees are still at the Green Tip to Pink stage in another week also.
Or does temp and bug activity not really matter?
