Late winter is a very important time for orchardists, because now is when you should apply dormant oil spray to your fruit trees. Dormant oil (also called all-seasons spray oil) smothers insect eggs on fruit trees before they hatch. You can apply it any time before buds start to open in spring; now is the ideal time.
Once the flower buds on your fruit trees begin to open, you should start applying all-purpose orchard spray every 10-14 days. All-purpose orchard spray is a mixture of insecticides and fungicides. Applied every 10 days to two weeks, it will kill many types of insects and discourage fungus growth. The first few sprays of the season do the most good, breaking the life cycle of most tree pests. Commercial orchards continue the spray schedule until harvest, but you can do with less spraying if you’re willing to tolerate a few blemishes on your fruit.
Fruit trees have many natural insect enemies, however it’s unlikely that they will be bothered by more than a few of these in a given season. Early control of the first generation of insects reduces the amount of control needed later in the season. The same is true of disease control. Most spraying is directed at funguses and blights, which threaten trees all season long but can be minimized by early control. In other words, get started right now and keep it up on a schedule. Once you see the problem, it’s much harder to control.
Disease pressure can be minimized by selecting disease resistant varieties. Old favorites whose names you recognize may not be the best choices. We recommend disease-resistant apples like Freedom, Liberty and Zestar, which require much less spraying. Another important step is annual feeding with trace-mineral-rich tree fertilizers like Espoma Tree Tone. A healthy, well-fed tree is less vulnerable to pests and diseases. Another important step to reduce insects and disease is cleaning up old fruit and debris around the base of the tree.
Growing fruit organically requires you to thoroughly study the interrelated cycle of fruit growth, pests, diseases and beneficial insects. Tree fruits are one of the most difficult crops to grow under a strict organic definition. Organic growers have to accept a high percentage of crop loss to insect damage.
Integrated Pest Management (IPM) is a middle ground between chemical control and strict organic methods. Like organic growing, IPM requires a high level of understanding and record-keeping, which sounds difficult but actually eliminates a lot of unnecessary work. Understanding the natural balance is a good thing and well worth the effort.
Professional orchard growers take the time to thoroughly research, understand and document all the factors of insect and disease control in their orchards. For the home orchardist this may be overwhelming. The tried-and-true approach of regular spraying, pruning and feeding will give you a satisfying fruit yield with the least time spent. Start the season off right by doing your dormant spray this week.
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers”. “Let’s Grow” is published weekly; column archives are on the “Garden Advice” page at www.goodseedfarm.com. For more information is available at www.goodseedfarm.com or call GoodSeed Farm Landscapes at (937) 587-7021.