One advantage to growing apples in Montana is the relatively short list of apple pests that can be detrimental to fruit and trees. The primary pests include codling moth and fireblight, which can severly damage a crop or quickly kill young trees. These pests should be controlled through an Integrated Pest Management (IPM) plan as described on the codling moth and fire blight sections.

Other insects like aphids, eriophyid mite (pictured above), and leaf rollers can be a nuisance to growers. If populations grow too large, these pests can damage fruit and cause long-term stress to trees. Providing good orchard nutrition and irrigation can help reduce damage from these secondary insect pests.

Other pathogens like scab and powdery mildew can also be damaging under certain conditions, including moist, warm springs. Planting disease-resistant cultivars and ensuring proper orchard sanitation can assist in reducing pressure from these diseases and reducing the need to treat them with fungicides.

If economic losses occur due to these diseases or insects, employ an IPM plan addressing cultural and mechanical controls followed by chemical spray applications. For more information on managing orchard pests and diseases, including spray schedules, refer to the Intermountain Tree Fruit Production Guide. Before purchasing or using any chemical, check that the product is labeled for use on apples and for the targeted pest. Applicators must read and understand the label fully prior to use.

Disclaimer: It is always the pesticide applicator’s responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registration, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned. The authors and Montana State University assume no liability resulting from the use of these recommendations.