Pest management for the home stone fruit orchard
Table of contents
- Pest management schedule
A surprising variety of apricots, plums and tart cherries can be grown in Minnesota. Although insect and disease pressure is lower here than in states to the south or east, there are insects and diseases that can destroy fruit and harm trees. Pest problems are best dealt with through the practice of Integrated Pest Management (IPM). IPM is a sustainable approach that allows gardeners to reduce pests to a tolerable level by using the best balance of cultural, physical, biological, & chemical management strategies. IPM takes into account the level of damage a pest is capable of causing, as well as the possible risks to humans and the environment associated with each pest management strategy.
In order for IPM to be effective, home gardeners must be able to recognize common pests of stone fruits and the damage they cause. Gardeners can find additional help identifying common pest problems by using the online diagnostic tools What insect is this? and What's wrong with my plant? Or by sending a sample to the UMN Plant Disease Diagnostic Clinic.
General cultural controls to minimize insect pests and diseases
Information on planting and caring for plums, cherries and apricots can be found in the publication: Stone fruit for home gardeners.
Plant stone fruit in a well-drained soil or amend the soil to improve drainage. When possible, avoid planting in low areas. Low areas often have wet soils that can lead to root diseases. Trees located in low areas also suffer more frost damage and winter injury than trees located on higher ground or hill sides.
Pruning is a key IPM tool for stone fruit production. Young fruit trees should be pruned each year to create an open and healthy branch structure. Detailed information about properly pruning young fruit trees can be found in Stone fruit for home gardeners. Pruning stone fruits is best done in March or April, shortly before bloom, and this is also the best time to look for problems with branches in trees. Inspect each tree for crossing branches, dead branches or branches with cracks, discolored bark or abnormal growths or swellings. Branches that are crossing and touching often rub together, creating a shallow wound that can allow wood rotting fungi to enter the tree. Branches with cracked or discolored bark or with abnormal growths may be infected with a pathogen. Prune out any suspicious looking branches 4-6 inches below visible symptoms. Infected branches should be removed and destroyed. Remove enough branches so that sunlight can reach the center of the tree. Proper pruning will allow fruit and leaves to dry more quickly after rain, resulting in lower disease pressure.
Keep the area within two feet of the trunk free of weeds for the life of the tree. Competition from weeds can reduce growth more than 30%, especially during the planting year. When planting trees in a lawn, cut and remove the sod in a section about four feet in diameter where the tree will be planted. In most lawns, few weeds will sprout where the sod was removed. The few weeds that do sprout can be controlled with mulch around the trees. Wood chip mulches control most weeds and contribute organic matter to the root zone. Keep the mulch a few inches from the trunk. Landscape fabric will control almost all weeds, but must be removed after several years. Straw mulch is not advised, because straw mulch attracts mice, which can then feed on the bark of the fruit trees. Removal of weeds near the tree also helps to minimize mouse habitat.
In IPM, pesticide sprays are used only when cultural controls are not effective or as a supplement to cultural controls. If using pesticides, gardeners should choose an effective product that has the lowest impact on human health, non-target organisms like bees, and the environment. Information on using pesticides safely for home gardeners can be found at the Pesticide Environmental Stewardship website and the National Pesticide Information Center website. Information on the correct way to apply specific pesticides can be found on the product label. If pesticides are necessary, always use them exactly as directed by the product label as mandated by federal law.