No problem with painting in the cold, other than it may not dry, and the only risk in painting the trunks white is you may get some on your jeans. Commercial orchards have been doing it for 100 years.

I tried John Bunker's method of mixing drywall joint compound in the paint and had a pretty good year of avoiding borers this year; could it indeed work?...

Applenut

applenut what ratio/mix of joint compound to paint are you using? I'm sure a lot of us are interested if it works. At less than $10/5 gal. joint compound would be a no-brainer.
Dan

Steve,
Fedco recommends the painting of tree trunks with latex/joint compound.
" After years of experimentation, I think that painting is the best deterrent.
I�ve tried a number of recipes and this is my favorite. It�s easy and requires
no hard-to-find ingredients. Mix white interior latex paint with joint
compound. (The stuff you smear on sheet rock joints and nail holes�you
can buy a small tub at any hardware store. Some exterior paint formulations
contain ingredients that can harm the underlying phloem.) The consistency
should be thick but still quite easy to paint, not glob
on. Repaint periodically or each year
as needed. This mix will help
deter borers. It will also make for
easy detection of any infestation
you may have. Look for the
frass! Using the paint method, you
will also need to put some sort of screen
or plastic rodent protector around the trunk
during the winter months.
We are experimenting with a
borer-protection formula using more benign
ingredients. It doesn�t last or adhere as well
as the paint-joint compound mixture, but it
appears to work fairly well.
2 qt quick lime
4 gal milk
1 gal boiled linseed oil
Mix well. Thicken as needed with clay or
Surround (available in the
Organic Growers Supply
section of the Fedco Seeds catalog).
Ap"

I applied an approx 20% mix but it may have been too much because a lot of it washed away. I reduced it to 10% with better adhesion. Flat indoor latex.
Some think I'm nuts for putting a shot of sulfur/lime for "good measure". Some question the logic to this practice, but Fedco is playing around too. I like the idea of having the aphids' ant-servants have to traipse their way through the chemical wasteland!
Noogy

I've been using the joint compound/latex paint mix for a couple years. I was concerned if it would allow the bark to expand and grow properly, but the trees seem to be doing okay, and I've not seen any borers. The compound cracks up and needs repainting annually, unless you want to experiment with whether brown streaks of new bark between the previous year's white covering heat up over winter and crack. I have apples, sour and sweet cherries, pears, apricots, and plums. I am glad to hear from others who are trying it.
Northwoodswis

I think exterior latex may contain Zinc compounds as a fungicide. That's why they recommend interior latex.

I've painted with exterior latex and not seen any problems, but KS is a lot different climate than Maine (Fedco). Milder winters and a longer growing season allow some practices that trees in a harsher climate wouldn't tolerate.

Fruitnut, why would zinc be harmful? It's sometimes used as a foliar spray and I can think of one fungicide that contains significant amounts of zinc (Ziram).

Would using the latex/joint compound mixture in the fall provide sufficient protection to allow use of tanglefoot over the joint compound in the spring? I just might paint a few upper branches to see what baddies I may catch.
Dan

I would think you could ring some tanglefoot over the joint compound, although some of the joint compound could flake off on occasion due to the expanding trunk and weathering, so you would want to monitor it frequently to be sure gaps don't develop where pieces of the joint compound flake off. I've never tried using tanglefoot, though. Northwoodswis

Tanglefoot...great stuff. You can rejuvenate sticky phero/chem traps or make your own. I've seen it used for drosophila sp? fruit fly with vinegar in a 2 liter bottle. Sure lets you see what's out there. Nothing like a crash course on drosophila management. Walking insects like ants/aphids, mites, also. You can see the ants catering to the aphids. In combo with other agents, can reduce #s greatly.

I've read on a couple of occasions that exterior latex is now approved by "experts". Unfortunately I don't have the info to back this up and would myself use interior just to feel completely safe about it. I believe that exteriors that include fungicide advertise the fact on the label so that should be easy enough to avoid, right?

I went ahead and did a search and most (not all) of the university recommendations I found specifically recommended the use of exterior latex with no caveots. I believe the latest is to use exterior and not interior latex.

http://nysipm.cornell.edu/%5C/grantspgm/projects/proj06/fruit/kain.pdf

Here's from Cornell.