Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/9/2009
Publication Date: 5/1/2010
Publication URL: http://hdl.handle.net/10113/43016
Citation: Neven, L.G., Hansen, L.D. 2010. Effects of Temperature and Controlled Atmospheres on Codling Moth Metabolism. Annals of the Entomological Society of America. 103(3):418-423. Interpretive Summary: Codling moth is a pest of apples, pears, and stone fruits in the U.S. Many countries require the fruit to undergo treatments to kill any potential pest that may be inside the fruit. To this end, high temperatures in combination with low oxygen and high carbon dioxide, called controlled atmospheres, are used to kill this pest. The combination of heat and controlled atmospheres kills this pest much faster than either heat or controlled atmospheres alone. In order to make treatments more effective and provide higher quality fruit, it is important to understand how these combination treatments kill the pest. Scientists at USDA-ARS and Brigham Young University tested the effects of various combinations of the treatments to determine whether the heat, low oxygen, or high carbon dioxide provided the most stress on mature codling moth caterpillars. In addition, a biochemical indicator of energy reserves and metabolism was measured. Heat treatments under low oxygen and high carbon dioxide significantly reduced the insect’s metabolism and its ability to withstand a heat treatment. Low oxygen impaired the ability of codling moth to generate energy stores, whereas high carbon dioxide inhibited its ability to utilize energy stores. Without the ability to make or use energy stores, the insect cannot survive heat treatments. Identification of the effects of controlled atmospheres on codling moth metabolism will help identify critical levels of oxygen and carbon dioxide to use to reduce the cost of combination treatments, thereby making it more economical for the fruit industry.
Technical Abstract: Although controlled atmosphere temperature treatments are effective in controlling codling moth in fruit, the mechanism by which this combination treatment kills the larvae is unknown. Differential scanning calorimetry was used to determine the effects of elevated temperatures, low oxygen, and high carbon dioxide on the metabolic heat rate of 5th instar codling moths. Total ATP levels were also determined. Metabolic heat rates in air increased from 0 to 30 degrees C and decreased above 30 degrees C. Heat rates measured isothermally at 23 degrees C under decreased oxygen or increased CO2 were lower than those in air with the lowest in 1kPa O2 and (1kPa O2 + 15kPa CO2). Continuous temperature scans from 23 to 44.5 degrees C under low oxygen and high CO2 atmospheres produced lower metabolic heat rates than scans under air. Low oxygen atmospheres produced the lowest ATP levels, and high concentrations of carbon dioxide produced the highest ATP levels. These results indicate that heat treatments under controlled atmospheres have a dramatic effect on codling moth metabolism, low oxygen prevents ATP synthesis and high CO2 prevents use of ATP.