Comparison of Predatory Performance among Three Ladybird Species, Harmonia axyridis, Coccinella septempunctata and Hippodamia variegata, Feeding on Goji Berry Psyllid, Bactericera gobica

The psyllid Bactericera gobica is a serious pest in goji berry orchards. The current primary psyllid control methods involve chemical pesticides, which pose potential risks to human health and the environment. The implementation and promotion of biological control agents should receive increased attention as an alternative approach to safeguarding goji berry orchards. To compare the predatory performance of three potential biocontrol agents of psyllids, including Harmonia axyridis, Coccinella septempunctata and Hippodamia variegata, the functional response and intraspecific interactions of adult ladybirds were studied under laboratory conditions. We observed a significantly higher searching efficiency (0.84 +/- 0.09) in H. axyridis when preying on psyllids compared to H. variegata (0.55 +/- 0.05), whereas the handling time for psyllids was considerably longer in H. axyridis (7.33 +/- 0.83 min) than in H. variegata (5.67 +/- 0.97 min). The impact of intraspecific interactions on H. variegata (0.44 +/- 0.04) was significantly greater than that on C. septempunctata (0.29 +/- 0.03), whereas the maximum consumption by C. septempunctata (223.35 +/- 41.3) significantly exceeded that of H. variegata (133.4 +/- 26.9). Our study suggests that each of these three ladybird species possesses distinct advantages as a potential predator of psyllids. However, further field studies are required to determine the most promising ladybird species for rapid impact through inundative biological control, taking into consideration the specific environmental adaptability of each ladybird species. The present study is expected to provide evidence that supports the potential of incorporating promising ladybird species as an effective biological control agent in goji berry orchard management programs.