Fruit Quality and Tree Growth

Thinning of fruit with plant growth regulators promotes return bloom, improves fruit size and color, and reduces limb and tree breakage from excessive crop loads. Plant growth regulators may also be used to control excessive vegetative growth, improve fruit quality (finish, shape, red color, maturity, cracking) and delay fruit drop which can reduce fruit losses and increase fruit size.

Chemical practices: Plant growth regulators are typically used in 1 to 3 applications for chemical thinning and improving fruit quality, and 1 application for drop control near harvest. Multiple applications may be used in some situtations to control excessive vegetative growth.

Cultural practices: In some orchards fruit is thinned by hand, as a substitute for or follow-up to chemical thinning.

Plant growth regulators are especially critical for thinning and preventing drop of fruit. Hand thinning of fruit is not economically practical, and failure to adequately thin results in small fruit and poor return bloom. Failure to prevent fruit drop with plant growth regulators can result in excessive fruit loss at harvest. During seasons of crop loss due to frost, application of a plant growth regulator can be a critical management tool to control excessive vegetative growth and prevent tree crowding.

Rodents

Meadow and pine voles can cause significant tree losses by girdling the trunk and roots of apple trees. This damage usually occurs during the late fall, winter, or early spring, when more desirable ground cover becomes dormant or frozen. Rodenticides, such as zinc phosphide, chlorophacinone and diphacinone are used by most growers as part of an IPM program to manage vole populations.