Location: Fruit and Vegetable Insect Research
2013 Annual Report
1)Determine critical parameters (i.e. photoperiod, chilling requirement) for diapause induction and completion in apple maggot from Washington State..
2)Determine critical parameters for growth and development of apple maggot and Western cherry fruit fly under climatic conditions specific for tropical regions. During this past year we collected over 20,000 apple maggot pupae from field infested fruits from Western Washington State. These pupae were used in experiments to examine the impact of temperature, humidity, and day length on fly emergence. These data are critical to develop accurate ecological niche models to determine the potential of this pest to establish and spread in countries importing U.S. apples. We conducted studies on metabolic heat rates and respiration of apple maggot pupae following cold storage and exposure to various day length and temperature conditions using differential scanning calorimetry and oxygen uptake monitoring. We also determined the lipid and carbohydrate levels of these pupae. We determined apple maggot cold hardiness using the differential scanning calorimeter. We determined that pupae take approximately 10 days to fully develop cold hardiness by suppressing their whole body supercooling points through the removal of gut contents, increases in lipid content, and binding free water. These data provide critical information on the physiological mechanisms of diapausing apple maggots and their potential to establish and spread in countries where they are not currently known to exist. The results of the metabolic, cold hardiness and emergence patterns under various day lengths and temperature conditions were used to develop a model to predict apple maggot potential to spread in other countries importing U.S. apples. These models will be used to maintain and expand exports of apples where apple maggot is a pest of quarantine concern, but is predicted to be unable to establish a population.