Spray oil questions (continued)

[marknmt]

Continuing the discussion from Anyone make their own oil spray in large quantities?:

[disc4tw]

@disc4tw

I have seen this in a few posts and books and being new, if you don’t mind I have a few questions -

What is the benefit of spraying trees with oil?
Do you spray the entire tree or just the lower portion of the trunk?
I assume the dish soap helps the mixture to “stick”?
Should this be done more than once per year?
Are there certain species this practice benefits most (pears, apples, peaches, cherries, pawpaws, persimmons etc) and are there any that do NOT need sprayed?

Here is what we started with for questions.

[disc4tw]

@Chills

Spraying with oil helps to smother insects and their eggs. I use a lime/Sulfur oil which also supposedly helps with fungal issues as well.

This brings up another question - are their specific benefits to using a particular kind of oil?

@r8f1k

To my knowledge, the oil suffocates insects that have overwintered in the tree. This needs to be done before bud break when there are no leaves or flowers. It should be put on all tree wood. As I understand it, the soap acts as an emulsifier to help make the oil ‘mix’ better than it would otherwise with straight water. I have heard that it is to sprayed on most any fruit tree. Here in southern Wisconsin, we do it at the end of February at the earliest and through the first three weeks of March up to bud break. It will get washed off by rain, snow, etc., but it does help.

This makes sense to me. Diesel fuel is suggested to be mixed with certain herbicides to help the chemicals stick to leaves. Obviously this is not the strategy you want for GROWING trees haha. I wonder if using a more environmentally friendly plant based soap like Seventh Generation is a good idea for the oil spraying?

@Bradybb

Since we don’t know where the critters are laying in wait,yes,the whole tree is sprayed.
Because water and oil don’t mix too well,the soap helps to mingle the two together.
It depends on the problems.I usually do it during late Winter or early Spring,just before bloom,to combat Curly Leaf Aphids in my Plum trees.

That is good information for plum trees! Does anyone else have thoughts on spraying regimens for other specific fruits? I am most interested in pears and apples personally. I imagine persimmon, pawpaw, and jujubes likely do not have many issues.