Prune and Spray Deciduous Fruit Trees
Finish pruning dormant deciduous trees and vines before leaf buds start to grow. Also spray them with horticultural oil before buds begin to open to control overwintering insect pests. When new growth begins, feed them with a nitrogen fertilizer.
If you have peach or nectarine trees that have not yet begun to bud, now is the time to spray to control peach leaf curl. Two fungicides used to control debilitating peach leaf curl in peach and nectarine trees have been taken off the market. To prevent this disease, gardeners can make their own fungicide by following the directions in UC Pest Note 7481, Bordeaux Mixture (do an internet search for UC Pest Note 7481).
The process requires buying a small quantity of copper sulfate and agricultural lime to make a stock solution of each chemical. Combine them and dilute with water to make the Bordeaux spray, which is applied twice while the trees are dormant.
For more on peach leaf curl, consult UC Pest Note 7426 at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7426.html