Spraying fruit trees is a standard practice farmers and gardeners take to help control plant diseases and insect pests and also to provide needed nutrients. You can choose from many brands of chemically based products or those containing natural ingredients such as sulfur. Whichever type of sprays you prefer, it is important to spray your tree regularly. General purpose sprays take care of both insects and fungal diseases.
Fertilizer Sprays in Early Spring
When your fruit tree is healthy, it is better able to resist diseases and insect attacks. In addition to the granular or liquid fertilizer you give your tree, an annual foliar spraying of compost tea can boost your tree's health. Mix 1 quart of organic compost in 5 gallons of water and stir the mixture every day for one week. Strain it and then spray in early spring, when your tree begins to develop leaves or flower buds.
Dormant Spray in Winter
Dormant oil is also called horticultural spray. Different types of oils, such as mineral oil or cottonseed oil, control insects such as mites, aphids and scale as well as diseases such as powdery mildew. Spray dormant oil on your tree during late winter or early spring, before the tree starts to produce new leaves or flower buds. The exact timing depends on your climate zone: in more northerly states, spray dormant oil in February or March. In more southerly regions, spray earlier in the year, depending when you have noticed your tree developing foliage in previous years.
Fungicide Before Bud Break
Spray your fruit tree twice with either a natural sulfur-based fungicidal spray or a spray made from chemicals. First, spray when the flower buds first begin to develop in early spring. When the buds grow larger and swell, but before they open, spray again. This lapse of time is normally 10 to 14 days. Always thoroughly saturate your tree with the spray you have chosen and follow label instructions for effectiveness and safety.
Combination Spray When Petals Fall
While your tree is blooming, watch closely for signs of petals dropping. When about 90 percent of the petals have fallen, don't hesitate: spray your tree with a combination spray to control both diseases and insects. Spray with the same product again one week later, taking care to completely cover both the upper and undersides of all leaves.
Campbell's Nursery in Nebraska recommends using a combination spray every 10 days through the summer, until two weeks before you begin to harvest your fruit.