Over the past few years we have heard about beneficial insects like honey bees and bumble bees being killed by pesticides or poor management practices. What home orchardists need to be working toward is a pest control strategy that hits the bad guys pretty hard but leaves the secondary pests and the predators alone, while being softer on the environment and the homeowner.
Today, we have some effective new tools and new integrated pest management-based systems that integrate lots of control practices without the negative impacts.
Most home orchardists in Douglas County have apple and pear trees because they grow well here on a wide variety of soil types, and are not as frost sensitive as some of the stone fruit that bloom very early. Generally the only real difficulty in growing nice apples and pears is controlling codling moth and apple scab. If you follow just a few timely steps this season you should be successful in producing nice quality fruit.
During the growing season you will want to have a pheromone trap in one of your apple or pear trees to attract codling moths. Traps can be purchased at local garden or farm stores. Traps are usually orange for fruit tree pests and fold into a tent shape. The traps will have a removable bottom insert that is sticky that will catch pests.
The trap kit should include a pheromone lure that lasts about eight weeks. This lure will need to be put on the sticky bottom insert of the trap. It usually takes two lures to cover the codling moth season until the end of September.
Using the traps is not a stand-alone control but it will improve the timing of your sprays.
You will want to make your first codling moth spray when you get five or more moths in your trap in one week. That first spray usually happens in the last half of May or early June.
The first spray should be one of the low toxicity products that are now available for homeowners. Spinosad is one product that works well. Cyd-X is a viral compound that is very effective when used in a rotation with Spinosad. Horticultural oil will also work but should not be used when temperatures go above 86 degrees to prevent leaf burn.
At the end of each week, clean out your trap of previous moth catches. Keep monitoring your pheromone trap on a weekly basis. After your first weekly catch with five moths, the new threshold for spraying will now be two codling moth in any one week.
When you plan your spray program make sure to switch products to one with a different mode of action each time you spray. Using a rotation of products makes it very difficult for the insect population to develop resistance to your pesticide. If you need additional sprays during the summer, go back to the first product and keep alternating.
Other products can be worked into the codling moth spray rotation if desired. Surround, a Kaolin clay product, is an irritant to the codling moth and is not toxic to people or animals. This product will cover the plant with a white coating but does not harm the trees.
I have found that I get about 1-2% damage in apples and less than 1% damage in pears when using this system at my home. Other steps you could add to a home orchard program would be to use a tangle-foot ring of sticky material around the tree trunks to stop the larvae from making it back to the ground to pupate.
Putting a cardboard collar around the trunk will also work to reduce populations. The larvae crawl to the cardboard and pupate. You can remove the cardboard and kill the pupae periodically during the summer.
You can also use a dormant oil or supreme oil in winter to kill insect eggs in the tree along with your winter fungicide. Cleaning up fruit drops when they occur will also reduce pest populations.
Another possible step in this system includes using a fall or spring spray of parasitic nematodes when the tree trunk is wet from a rain and the temperature is still above 60 degrees. The nematodes will attack over-wintering codling moth larvae that are hiding in the tree bark crevices.
As we move into June you may need to use one fungicide application for apple and pear scab if we have a forecast for a late shower or two that is expected to persist for a couple days. Two homeowner available fungicides for apple or pear scab are Immunox and Captan.
Give this program a try if you have apples and pears and I think you will like the results. Remember to combine this program with a few fungicide sprays during dormancy and in the spring.
Do a good job of pruning to open your tree to light and air movement to aid disease control. This will also help your sprays get on target. And thin your fruit to singles to minimize worm pest.
Steve Renquist is the Horticulture Extension Agent for OSU Extension Service of Douglas County.