Effectiveness of Harmonia axyridis Pallas reared on Ephestia kuehniella Zeller eggs as a biological control for Aphis craccivora Koch

Author of the article:SUN Li1, 2, 3, 4** CHEN Xia1, 2, 3, 4 ZHANG Yan-Xuan1, 2, 3, 4*** ZHAO Ling-Ling2 LIN Jian-Zhe

Author's Workplace：1. Institute of Plant Protection, Fujian Academy of Agriculture Sciences, Fuzhou 350002, China; 2. Research Center of Engineer and Technology of Natural Enemy Resource of Crop Pest in Fujian, Fuzhou 350002, China; 3. Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou 350002, China; 4. Fuzhou Scientific Observing and Experimental Station of Crop Pests of Ministry of Agriculture, Fuzhou 350002, China

Key Words： Harmonia axyridis Pallas; eggs of Ephestia kuehniella Zeller; Aphis craccivora Koch; predatory effect

Abstract：[Objectives]  To assess the effectiveness of Harmonia axyridis Pallas, reared on Ephestia kuehniella Zeller eggs, as a biological control for adult bean aphids, Aphis craccivora Koch, and determine the optimum H. axyridis release density required for effective biological control of this aphid. [Methods]  The predatory efficiency of H. axyridis reared on either E. kuehniella eggs or aphids, on adult bean aphids, A. craccivora, was assessed in a laboratory. [Results]  Predation by newly emerged H. axyridis adults on A. craccivora was of the Holling-Ⅱtype. The theoretical maximum predation rates of H. axyridis reared on fresh eggs, UV-killed eggs, frozen eggs , frozen eggs with honey, or aphids, were 88.20, 97.73, 78.64, 101.81, 107.70 prey·d^-1, respectively, and there was no significant difference between these 5 treatments in average predation rate on aphids. At the same prey density, the search efficiency of H. axyridis reared on these five different diets was also very similar. After fitting the new Holling functional response model, the highest possible H. axyridis density without inter-specific competition, 31.89, was the best for biological control of aphids. [Conclusion]  H. axyridis adults raised on E. kuehniella eggs could control aphids as well as those raised on aphids and the predatory functional response model of both groups was of the Holling-Ⅱtype. The parameters of the predation function of H. axyridis fed on frozen eggs with honey were most similar to those of the control. Therefore, in terms of predation efficiency, frozen eggs with honey are the best diet for H. axyridis. Frozen eggs are easy to preserve and therefore suitable for the large-scale production of H. axyridis.