Micromus variegatus and Scymnus interruptus: two new promising candidates with potential for early aphid control in sweet pepper crops

Abstract: Aphids are a major pest in sweet pepper. Current biological control strategies are
mainly based on frequent releases of parasitoids and the gall midge Aphidoletes aphidimyza
(Diptera: Cecidomyiidae). However, these natural enemies are not always effective due to the
presence of disruptive interactions with other biocontrol agents or their inability to establish in the crop when aphid densities are low. The purpose of our study was to screen, test and
incorporate new potential natural enemies to the current biological control programs to be used preventively in the crop, when aphids are still absent. Two new candidates were selected based on their characteristics, against the aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae): the micrococcinellid Scymnus interruptus (Goeze) (Coleoptera: Coccinellidae) and the brown lacewing Micromus variegatus (Fabricius) (Neuroptera: Hemerobiidae). Under laboratory conditions, different alternative and supplemental food sources that might be beneficial for their establishment prior to aphid infestation were tested. Later on, in a greenhouse trial their establishment, complementarity and effectiveness at low aphid densities were assessed. Furthermore, we evaluated their interactions and compatibility with other biocontrol agents commonly used in sweet pepper crops. Our results showed that both M. variegatus and S. interruptus are promising preventive biocontrol agents against aphids. They can establish in the crop when aphids are absent and control early infestations. Furthermore, we demonstrate that both candidates are compatible and may be combined with currently used biocontrol agents of sweet pepper crops.