2013 Annual Report
1a.Objectives (from AD-416):
Develop oxygenated phosphine fumigation treatment to control codling moth and apple maggot in apple.
1b.Approach (from AD-416):
Codling moth and apple maggot eggs, larvae at different instars, and pupae will be subjected to oxygenated phosphine fumigations at low temperatures to determine the most tolerant stages. The most tolerant life stages will be further tested to determine an effective oxygenated phosphine fumigation treatment. The treatment will then be tested in large scale treatments with both insects and apples to verify its efficacy and evaluate impact on apple quality.
Both codling moth and apple maggot will be reared on artificial diet and will also be reared on apples for fumigation treatments. Susceptibilities of codling moth and apple maggot on artificial diet and in apples to oxygenated phosphine fumigation treatments will be compared. A treatment which can control the most tolerant stage(s) of codling moth and apple maggot will be determined, and the treatment will then be further evaluated to determine impact of apple quality.
Commercial apples of at least three varieties will be obtained from commercial packers, and fumigated in 442 liter metal chambers together with apples infested with codling moth and apple maggot at 1C in walk-in coolers. The chambers will be flushed with oxygen gas first to establish 50-60% O2, and then diluted pure phosphine at 1.6% from a compressed cylinder will be released into the fumigation chambers to conduct fumigation treatments.
After fumigation treatments, infested apples will be incubated to allow any surviving insects to recover and commercial apples will be stored together with controls at 1C in a walk-in cooler. Infested apples with late larval instars will be dissected to examine larval mortality one day after fumigation. Apples with eggs and earlier instar larvae will be reared to allow any survivors to develop to late instars, and the apples will then be dissected to determine if there are survivors.
Apple quality will be evaluated one month after fumigation. Apples from treatments and controls will be compared for visual appearance, flesh color, stain, and firmness. A color spectrum photometer will be used to measure color for apples with uniform colors. Skins of apples will be peeled off to evaluate flesh color. A potentiometer will be used to measure firmness of apple flesh.
The project directly addresses Sub-objective 1B (Develop oxygenated phosphine fumigation treatment to control codling moth in apple) of the parent project. This is the first year report of a three year project.
In the first year (FY2013), a codling moth colony was successfully introduced from Canada and established on artificial diet in the Animal and Plant Health Inspection Service-Center for Plant Health Science and Technology lab in Salinas, California. A technician was hired to assist rearing codling moth. However, because of the lengthy process of introducing codling moth, no fumigation treatment has yet been conducted. Fumigation tests will start as soon as codling moth becomes available.