Relative Efficacy of Two Clades of Aphelinus mali (Hymenoptera: Aphelinidae) for Control of Woolly Apple Aphid (Hemiptera: Aphididae) in China.

Aphelinus mali (Haldeman) is an effective natural enemy used in China to control woolly apple aphid. Previous studies have found that populations of A. mali in China fall into two distinct genetic clades. We found that one of these, the Shandong clade, is more effective as a biological control agent than the Liaoning clade. The control ability of the Shandong clade of A. mali (a/Th = 2.447) was found to be stronger than that of the Liaoning clade (a/Th = 1.278); the search parameter (Q) and the mutual interference parameter (m) of the Shandong clade (0.1166, 0.2567) were both significantly higher than that of the Liaoning clade (0.076, 0.185). The egg production and life (64.4 ± 10.44 eggs and 16.26 ± 1.04 (female), 13.54 ± 0.75 (male) days, respectively) of the Shandong clade were both significantly higher than they were for the Liaoning clade (30.67 ± 4.02 eggs and 9.34 ± 0.67 (female), 7.64 ± 0.48 (male) days, respectively), and the Shandong clade had a longer oviposition period for one oviposition (Shandong 86.6 s, Liaoning 61.4 s). We expect, in Shandong Province, the pest control ability of the Shandong clade of A. mali to be better than the Liaoning clade.