Fruit trees are prone to insect and disease problems. Preventive spraying is necessary for good fruit production. The first spray is dormant oil, usually in late February or early March. Considered organic, dormant oil physically smothers overwintering insect eggs and some fungal spores. It should be applied when temperatures are over 40 degrees for at least 24 hours. The rest of your spraying will be a fungicide and insecticide combination, organic options are available. Apply the combination product when the flower buds swell but before they open. Spray again after the petals fall off. Never spray while they are in bloom, to protect the bees and ensure pollination. Further spraying depends on the product and type of fruit, read the label for specific instructions.