Photo-selective nets (PSNs) affect predation by Harmonia axyridis on Myzus persicae

Abstract

Photo-selective nets (PSNs) can increase agricultural crop production by modifying the quantity and quality of light that reaches the plants. PSNs also have the potential to affect arthropod pest populations and their natural enemies. The present study aimed to assess the impact of PSN systems on coccinellid predation. Experiments were carried out in microcosm conditions to evaluate the efficiency (prey localization and predation) of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), when preying on the green peach aphid, Myzus persicae (Sulzer), on potato plants. Three colors of nets were tested and compared to control (no net): black SN (standard net), pearl PSN, and red PSN, using H. axyridis third-instar larvae (L3), females and males. We hypothesized that pearl and red PSN and black SN would alter the predator behavior, delaying the time to aphid colony localization, or by reducing overall aphid predation. Our results showed that aphid colonies were not affected by any PSN or the black SN in the absence of predators. Aphid colony localization by adult coccinellids was delayed under black SN, and favored under pearl PSN, but overall aphid predation was unaffected by net type. There were no significant differences among treatments in interplant movement of L3, females, or males. We conclude that, under laboratory conditions, pearl PSN, red PSN, and black SN can affect aphid colony localization by H. axyridis, but do not affect predation efficiency. Subsequent trials in the field would be required to further clarify the effects of PSNs on H. axyridis foraging behavior.