Skip to main content
ARS Home » Pacific West Area » Wenatchee, Washington » Physiology and Pathology of Tree Fruits Research » Research » Research Project #436464

Research Project: New Active Ingredients for Pear Superficial Scald Control

Location: Physiology and Pathology of Tree Fruits Research

Project Number: 2094-43000-008-006-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Jul 1, 2019
End Date: Jun 30, 2022

Management for superficial scald control continues to be an industry challenge. The uncertainty of continued availability of ethoxyquin, market access issues related to its use, and ripening issues with 1-MCP treated fruit all contribute to a need for alternative scald control methods. A new chemistry, developed by our cooperators, has been shown to control scald on ‘Packham’s Triumph’. The formulation contains purified squalane from vegetable oil, which is likely the active ingredient. Squalane is an oily triterpane related to many triterpene cellular membrane, wax, and, possibly, cuticular components. The mode of action is unknown although preliminary evidence indicates it does not act as an antioxidant like ethoxyquin or diphenylamine. If so, this is a unique mode of action which, if determined, may yield new information to find additional active ingredients, risk assessment protocols, and cold chain management strategies to eliminate superficial scald from the pear cold chain. Objectives: 1. Test squalane-based formulation(s) for scald control of ‘d’Anjou’ pear. 2. Determine mode of action of this new active ingredient. 3. Determine any quality impacts and control of other appearance-related defects.

We propose to determine the efficacy and best use of the existing squalane-based formulation as well as analyze the mode of action. To accomplish this, we will treat multiple ‘d’Anjou’ lots from different growing regions and store them in air or controlled atmosphere (CA) storage evaluating appearance as well as fruit quality over commercially relevant storage durations. Multiple seasons and harvest maturities will be included in location. We will exhaustively analyze peel chemistry at critical points in the cold chain to determine changes squalane addition may provoke focusing on cellular membrane, wax, and cutin chemistry to determine mode of action. We expect to deliver information describing best use of this formulation in relation to current CA storage and cold chain management practices, and an improved understanding of pear scald.