| Summary: | The aphid, <i>Aphis gossypii</i> Glover, is identified as a significant pest that causes severe damage to goji berries in China. To analyze the ladybird consumption of aphids, the functional responses of three ladybird species, <i>Harmonia axyridis</i>, <i>Coccinella septempunctata</i>, and <i>Hippodamia variegata</i>, and intraspecific competition among ladybird individuals were evaluated under laboratory conditions. Moreover, the practical impact of ladybirds on aphid population reduction was investigated in semi-field conditions. We found that all adult ladybirds of the three species exhibited a type II functional response toward aphids. According to Holling’s disc equation, <i>H. axyridis</i> exhibited the highest searching efficiency (<i>a</i> = 0.79), while <i>C. septempunctata</i> had the shortest handling time (<i>T</i><sub><i>h</i></sub> = 5.07 min) among the three ladybird species studied. Additionally, intraspecific competition had a greater impact on <i>H. variegata</i> (<i>m</i> = 0.41) compared to the other two ladybird species. The semi-field study demonstrated that <i>H. axyridis</i> (83.9% reduction) and <i>C. septempunctata</i> (78.7% reduction) exhibited higher efficacy in reducing aphid populations compared to <i>H. variegata</i> (27.3% reduction). This study suggests that <i>H. axyridis</i> and <i>C. septempunctata</i> exhibit potential as effective biological control agents against aphids on goji berry plants and highlights the importance of considering intraspecific competition. However, the results obtained from laboratory and semi-field studies cannot be directly extrapolated to field conditions due to the simplification of these experimental systems. Future field studies are crucial in ensuring the effective implementation of a biological control program.
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