A Sustainable, Non-Chemical Thinning Method for US Midwestern Apple Producers: Novel Use of Anti-Hail, Insect-Exclusion Netting

Commodities

Practices

Achieving consistent crop loads of high-quality fruit is extraordinarily challenging. Apple producers rely heavily on thinning compounds to reduce their fruit set and meet their target crop level. Both under- and over-thinning have serious economic consequences. Furthermore, organic apple producers have very few labeled thinning compounds at their disposal; thus, expensive labor costs associated with hand thinning are required. There are numerous benefits associated with over-the-row netting systems, including but not limited to, exclusion of pests, hail protection, sunburn control, improved water use efficiency, and reduced chemical use.  For these reasons, many US apple producers have recently adopted netting systems; however, we have recently demonstrated that nets can also be used to solve critical fruit set and crop load management issues.  Achieving ‘target’ crop load via nets would substantially mitigate or eliminate cost-prohibitive and/or chemically-intensive thinning methods required to abscise superfluous fruit. Providing Midwestern apple producers with an alternative crop load management tool may also facilitate a transition to more sustainable, organic production given the dearth of options for thinning fruit. More broadly, netting can decrease chemical and insecticide applications and increase grower profitability for conventional and organic producers alike.

Over the past 5 years, we have demonstrated that netting can effectively produce commercial crops of apples in modern, high-density, tall spindle apple trees without the need for supplemental thinning on both commercial and University farms. Over this timeframe, we have optimized the timing of net enclosure, based on the percentage of open king bloom, for the high-value cultivars ‘Gala’, ‘Honeycrisp’, ‘Fuji’, and ‘SweeTango’. Netting canopies from pink to full bloom produced a positive yield response and generated commercial crops of high-quality fruit. The next step toward stakeholder adoption is to scale-up experiments to assess the practical use of netting and demonstrate reduced insect pressure and horticultural/crop production benefits. We propose to optimize and demonstrate net use on a commercial scale in our proposal entitled, A Sustainable, Non-Chemical Thinning Method for US Midwestern Apple Producers: Novel Use of Anti-Hail, Insect-Exclusion Netting. To achieve this, we have engaged commercial famers to collaborate with a research team on the design and implementation of nets to reduce crop load on diverse farms (both geographically and in management). With our commercial partners, we expect to demonstrate the benefits of netting on insect/pest populations and profitability and communicate and disseminate these findings to stakeholder and scientific audiences in a variety of forums.

We intend to investigate the economic and environmental impacts of netting on Midwestern apple production, and to provide stakeholders with recommendations based on commercial-scale trials.

 Producers will learn how to apply new production-system technologies to manage pests, hail and crop load and gain invaluable understanding of pollination processes and fruit set biology under controlled environment systems.

Growers will learn to use nets to manage fruit set and crop load, protect against biotic and abiotic stresses, reduce chemical and pesticide use, and increase their profitability. Organic producers will have an efficacious and reliable method at their disposal to reduce thinning pressure.