Choice, unblemished fruit is a challenge to grow. Pests love fruit even more than you do, and their feeding destroys fruit quality and quantity. Additionally, failure to control pests creates breeding sites that infest trees throughout the neighborhood. Even if you don't enjoy the fruit, control the pests. Good neighbors don't breed pests that destroy their neighbors' fruit.
Early season pests do not attack the fruit because it is not yet formed. The damage is to the tree, but that damage ultimately affects fruit size and quality. Many of these pests increase in number and attack the fruit later in the season.Aphids are familiar to most gardeners. They cause early emerging leaves to curl and as they feed they pass sugary materials through their bodies. They are usually controlled by predators including green lacewings and ladybugs. Insect predators don't hatch until after pest populations are active because they would have nothing to feed on. Aim pest control at those early season outbreaks because predators are not yet active. Watch for ants, because they protect aphids. Ants use the sugar from aphid excrement as a food source.
Scale is a non-mobile insect. It is seen as small, black or brown spots on the bark or fruit. Light infestations of scale cause cosmetic damage, while severe infestations cause fruit distortion. The crawler stage is highly susceptible to pesticides, but this stage is only present for about two weeks. During the rest of their life, they are highly resistant to pesticides because of the heavy waxy coating the insect produces over itself.
Spring temperatures also activate spider mites. Although their damage does not show until the weather turns hot, populations start building when the trees start to grow. Early control results in fewer problems later in the year. Plant-feeding mites are kept in check by predatory mites. Control mites by preserving predatory mites and controlling weeds where mites feed. Weed control in and around the orchard is critical so mites don't develop large populations.
Pest prevention is the best control strategy. Dormant oil is an excellent organic control. It is relatively nontoxic and very effective when used as directed. Oils are sold under many brand names, but all are highly refined petroleum oils. Insects and related pests breathe through tiny holes in their skin or exoskeleton. Oil clogs those openings and smothers the pests.
Apply oils when the green tips or flower colors first show. This delayed dormant application is more effective than a dormant season spray because the pests overwinter inside the buds or under the rough bark. In addition to spraying fruit trees, use the same spray on ornamental plants that are bothered by these troublesome pests. Spray when temperatures are warm for best results and don't use oil sprays within one month of using sulfur sprays.
Add Diazinon or another insecticide to increase the effectiveness of the spray. Pear psylla causes brown sticky fruit and leaves later in the season. If this pest attacks your pears, add Thiodan (endosulfan) to the spray. Apply this spray this week in the Salt Lake Valley.
Jonathan, Jonamac, Jonagold, Melrose and some other varieties are very susceptible to powdery mildew. Spray with benomyl (Benlate), Bayleton, Funginex or karathane every two weeks during the spring and early summer to help keep this disease under control. Powdery mildew eventually covers and destroys leaves, buds and twigs and also distorts and discolors the fruit.
Early season pest control does nothing to control most of the very serious pests that attack later in the season. Codling moth, cherry fruit fly and peach tree borer must all be controlled later in the season. Keep reading for timely updates on when to do this.
Fruit pest control is not always easy. Timely applications of preventative controls are the best defense against future problems. Work now to enjoy the payoff of luscious, juicy fruit next summer.