Here along the Central Coast we are blessed with one of the most amazing climates for the production of home grown fruit. Winter brings some critical responsibilities for your home orchard; one of these is spraying your tree with winter fungicides and oil.
Along with pruning, winter spraying ensures a healthy tree free of hibernating insects, deadly fungal and bacterial disease. Common fungal diseases we hope to control include blight, leaf curl and brown rot. Common bacterial diseases include fireblight, bacterial canker and blossom blast. There are some effective sprays that will go a long way to keep your home orchard healthy and in peak production for you and your family.
The first thing you will need is a good sprayer. This makes the job of treating fruit trees easier. The Ortho “dial a spray” offers a convenient dial for easy mixing when attached to a garden hose. When it comes to sprays, there are is a wide range of products available. The most common organically acceptable solutions include mineral oil, liquid copper and liquid sulfur. My favorite mineral oil is the “All Season” label. It can be used as an organic solution in season as well. The oil actually suffocates over-wintering insect eggs.
Both copper and sulfur sprays work well against fungus and bacteria. An important point to remember is that you should never use a sulfur product on apricot trees. The E.B. Stone label copper soap is actually a great all-around organic winter spray. You should also wait for 30 days before using sulfur after any oil spray treatments.
Late December through early March is the time to spray here along the Central Coast. When it comes to spraying your trees, you will want to be sure you’ve already pruned for the winter. In general you will want to do at least one dormant oil spray in the winter when the trees are leafless. Your fungicide spray is best applied before the flower buds open. Some folks will apply a second spray after all the flower petals have dropped as well. Never spray when any flowering is taking place as even organic sprays can kill bees.
Be sure to remove any leaf litter that has not fully composted around your trees. The litter can often harbor disease and pests. You will also want to choose a calm sunny day when spraying. Wind will inhibit a nice, even coverage on your tree. Most sprays are also harmful to fish, so make sure there will be no drifting of spray chemicals near a pond. When using any chemicals, even organic ones, it is always wise to wear gloves and glasses.
Sprays are generally purchased as a concentrate and mixed in the hose end sprayer. Be sure to follow the instructions on the bottle for the right dilution. For sulfur spray the concentration to be applied varies between ½ cub and 1 cup concentrate per gallon of water. For copper spray the concentration is generally 1 ounce per gallon of water. Some gardeners will actually apply oil at the same time as the sulfur spray.
Research performed by the University of California confirms that spraying your fruit trees over the winter will greatly increase your yield of healthy, tasty, home-grown fruit. There are countless gardeners that have discovered this. For more information and instruction, seek out the expert advice of your local nursery; after all, that is what its there for.