USDA NIFA (SCRI) and Washington Tree Fruit Research Commission
Lewis, K. (WSU Lead)
Blossom thinning is reported to mitigate alternate bearing in apple and increase final fruit size in both apple and stone fruit. Hand blossom thinning is expensive and requires a large workforce for a short time period. Efficacy and performance of chemical thinning is highly dependent on weather conditions, tree status and application methods. Organic producers have few products to chemically thin fruit. Project investigators have evaluated two non-selective mechanical string thinners and technologies for selective thinning. Field studies include the evaluation of the Darwin and Unibonn string thinners in apple and stone fruit. Replicated field trials compare mechanized bloom thinning, hand bloom thinning, hand green fruit thinning and chemical thinning. To evaluate treatments, data is collected on bloom removal, fruit set, fruit quality and yield. In addition, task efficiency and individual worker productivity is measured and economic analysis is conducted for each treatment.
If you would like more information about this topic or other developments in agriculture, contact Dr. Qin Zhang.