Managing diseases and insects in home orchards

Importance of controlling diseases and insects in commercial fruit districts

Because of recent changes in pesticide registrations, home orchardists must be diligent with their pest control to prevent damage to nearby commercial orchards. If you grow fruit trees for fruit production, it is critical that you help prevent the spread of pests to commercial orchards. (See “Required pest control programs.”) If you have fruit trees in your yard or landscape that are just for shade or beauty, you might consider replacing them with trees that do not attract pests that can damage commercial fruit trees. Contact your local Extension office for a list of some replacement trees.

Applying pesticides safely

There are many organic and synthetic formulations of pesticides for home garden use. Many are variations with the same active ingredient. Look for pesticides you can use on a wide range of fruit, nuts, vegetables and ornamentals, so you can limit the number of pesticides you need to buy and store.

The pesticides listed in this publication were chosen for how effective, available and safe they are. Always apply pesticides according to the label instructions—this is very important. The label has valuable application information and safety precautions to protect you, others, and the environment. Before you buy or open the container, read the label. Read it again before you mix, store, or throw the product away.

Be cautious when you use products that contain a combination of more than one insecticide and fungicide, such as “home orchard sprays.” Some of these products call for applications during bloom to control fungal diseases. If you also apply an insecticide during bloom, you run the risk of killing bees that are critical for pollination. A better strategy, especially during the spring, is to use products that contain only a single type of pesticide, and apply them only when necessary. In general, be careful when applying pesticides that are toxic to bees. Do not apply insecticides that are toxic to bees during bloom or when bees are foraging nearby. This may be less convenient, but it can save you trouble in the long run.

Not every effective pesticide is included here; it is not possible to list them all. Some of these other pesticide products are packaged in larger quantities for commercial growers, so they are not practical if your orchard has only a few trees. Check with your local Extension agent, Oregon State University Master Gardener™, or nursery professional for more information.

Managing diseases and insects without using pesticides

There are many cultural and biological techniques you can use to manage or prevent disease and insect damage. Consult your local Extension agent, OSU Master Gardener, or nursery professional for more information.

• Choose the proper cultivar for your climate and soil. Apricots are not well adapted west of the Cascades: wet springs prevent apricot fruit set and cause disease.
• Choose disease resistant cultivars. For example, Liberty, Prima, Akane, and Chehalis apples are resistant to apple scab, while Granny Smith and Gala are not.
• Water and fertilize the right way. Overwatering can cause root rot, and overfertilizing can increase disease and insect problems. A soil test is a first step in managing soil fertility, and analysis of leaf tissue samples gives you valuable information about the nutrient status of your trees.
• Proper pruning and fruit thinning. Proper pruning and fruit thinning improve fruit quality, air circulation and pesticide spray coverage.
• Good sanitation. Remove and get rid of (burn, bury or send to landfill) diseased branches and leaves. Remove and destroy old fruit from the tree and the ground. Do not use diseased leaves as mulch. Mow and shred or remove old leaves beneath fruit trees.
• Pest monitoring. Know which pests are likely to attack your trees and when these pests might appear. Create a routine for inspecting your orchard. Pheromone and sticky traps are useful pest management tools. Contact your local Extension agent or nursery professional for more information.
• Biorational pesticides. Insecticidal soaps and oils are effective against a wide range of tree fruit pests. You can use microbial pesticides like Bacillus thuringiensis (Bt) to control certain caterpillars.
• Biological control. You can enhance control by the pests’ natural enemies by limiting how many times you use pesticide sprays and by using selective pesticides when possible.
• Exclusion. In the home orchard, excluding certain pests can be a practical method. For example, bag individual apples in mesh baggies (fruit sox/orchard sox) to protect fruits from codling moth, apple maggot, and stink bugs. Another tactic is to cover entire trees in screen material to exclude pests.
• Tolerance. Some pests, such as leafrollers, are rarely a problem for the tree or the crop and they are heavily targeted by natural enemies. It’s a good idea to tolerate the presence of some pests at non-damaging levels.

Fruit

Apple

Commercial growers must control diseases and insect pests of apples. Most of the time, it is not practical for home fruit growers to try these control practices on large apple trees.

Apricots

Do not use sulfur products on apricots. They can injure buds, leaves and fruit.

Commercial growers must control diseases and insect pests of apricots. Most of the time, it is not practical for home fruit growers to try these control practices on large apricot trees.

Prunes and plums

Commercial growers must control diseases and insect pests of prunes and plums. Most of the time, it is not practical for home fruit growers to try these control practices on large prune or plum trees.

Nuts

Note: Several Oregon counties have ordinances that require home fruit growers to use minimum spray programs to prevent disease and insect spread to commercial orchards. See “Required pest control programs” for requirements in specific counties. Check with your local Extension agent if you are not sure.

Moss and lichen

Moss and lichen do not damage fruit and nut trees. Regular pruning and using the dormant chemical sprays (copper fungicides or lime sulfur) for disease and insect control will reduce the amount of moss and lichen in trees.

Pesticide safety tips

Most accidents occur during mixing. Wear rubber gloves and protect your eyes from spilling or splashing chemicals. Avoid getting pesticides on your skin and wash your hands when you finish. While spraying, wear a long-sleeve shirt, full-length pants, unlined rubber gloves, and goggles or some type of eye protection. Wash all clothes after spraying. See Using Pesticides Safely (EC 1497).

Never eat or smoke when using pesticides. Do not blow your nose during spraying, and keep your fingers away from mouth and nose.

Check your sprayer for leaking hoses, leaking connections, and plugged or worn nozzles. Clean filters to prevent accidents.

Mix the pesticide at the recommended rate on the label. Mix only the volume needed to complete the task. Don’t exceed the label rate. Putting more pesticide into the environment than you need for good control is wasteful and dangerous.

When you finish, clean your sprayer immediately and dispose of the rinse water properly as indicated on the label.

Apply pesticides at the right time and under the right weather conditions. Never apply pesticides when winds will cause the chemical to drift off the target area or when temperatures exceed 85°F. Be careful not to let pesticides contaminate neighboring ponds or streams. You are liable for any off-site damage that may result from your misuse of pesticides.

Store pesticides in a safe, secure place, out of the reach of children and in their original container. Never keep pesticides in beverage bottles or other previously used food or drink containers. Properly dispose of empty glass, metal, and plastic pesticide containers, after first rinsing them three times with plenty of water.

Accidents can happen. You can reach the Poison Center at 1-800-222-1222.

Required pest control programs

Several Oregon counties have ordinances that require home fruit growers to rigorously control pests to prevent disease and insect spread to commercial orchards. Doing that often involves a more exacting control program than those outlined in this publication.

Contact your local Extension office for details if you live in any of the following counties: Hood River, Jackson, Josephine, Lane, Linn, Marion, Polk, Sherman, Union, Wasco, Yamhill, Umatilla.

For more information

• Pacific Northwest Insect, Plant Disease and Weed Management Handbooks
• Stop BMSB: Management of brown marmorated stink bug in U.S. specialty crops
• IPM Pest and Plant Disease Models and Forecasting
• Using Pesticides Safely (EC 1497)
• How to Reduce Bee Poisoning from Pesticides (PNW 591)