Now that all your mummies and dropped fruit have been cleaned from under your trees and you have pruned all diseased branches and twigs, it is time to consider using an oil spray on your dormant fruit trees.

Spraying now can make a huge difference in the health and vitality of your trees, and help you harvest a bigger and better crop.

Horticultural oils — sometimes labeled “superior” or “supreme” — can kill the eggs of leaf rollers, aphids and mites, and also gypsy moths, tent caterpillars and other moths and caterpillars on the tree. The oil kills primarily by smothering and can only kill through direct contact.

Spraying from underneath can help insure more thorough coverage but must be done very carefully to protect the person who is doing the spraying.

As always, read the directions and precautions on the label and wear any safety equipment that is recommended. In this case, safety glasses and some type of face protection would be a wise choice. Also, be sure to wear closed shoes, pants and a long-sleeved shirt.

Even in the winter, some Californians do their yard work in shorts!

• UC Certified Master Gardeners are available to answer your gardening questions Tuesdays, Wednesdays and Thursdays from 9 a.m. to noon at 953-6112. Questions for this column can be submitted to ucmastergardener@gmail.com.