Use of protective netting in Washington State apple production

Washington State (WA) is the largest producer of apples in the United States. The major apple growing regions in WA are located in the semi-arid eastern half of the state which experiences harsh environmental conditions due to the rain shadow effect from the Cascade Mountain Range. The adoption of protective netting to reduce fruit sunburn and tree stress is gaining momentum in WA. The objective of this publication is to give the current status on the adoption of protective netting in WA. The information disseminated in this publication was collected from previous research conducted in WA and a survey done during the summer of 2017, representing 46,000 of the estimated 179,146 acres planted to apples in WA. Types of protective netting structures commonly used by commercial apple growers in WA are discussed. These are, namely, exclusion netting; continuous over-the-top; louvered or partial overhead; and drape netting. The benefits of using protective netting for WA apple growers are also discussed. The main benefit is the improvement in fruit quality through sunburn reduction. Other benefits include a reduction in hail damage, wind damage, bird pests, and insect pests, and an increase in water savings. At the time of the survey, the total acreage for apples using protective netting was 2,347 acres (approximately 5.1%); an additional 3,417 acres (approximately 7.4%) were planned to be covered with protective netting in 2018. The most common cultivars under netting were ‘Honeycrisp’ and ‘Granny Smith’. The survey identified establishment costs and the annual maintenance cost as economic considerations for using protective netting. In conclusion, protective netting is being increasingly adopted by apple growers in WA as an alternative to traditional sunburn mitigation strategies, like overhead cooling and sunburn protectants