Cryptic species Chrysoperla lucasina and C. carnea differ in predation of early Nezara viridula instars

Invasive pests increasingly threaten the stability of integrated pest management programs in greenhouse cropping systems, where biological control strategies are typically tailored to established pest complexes. Nezara viridula (Hemiptera: Pentatomidae) has emerged as a major pest in European greenhouses, where current biocontrol programs are poorly equipped to suppress it. Eight commercially available generalist arthropod predators commonly used in greenhouse solanaceous crops in Europe were assessed for their ability to suppress N. viridula. Their impact on its eggs and early nymphal instars was assessed through standardized laboratory assays, as well as greenhouse cage trials using fruit-bearing sweet pepper plants. Predation was observed mainly among larvae of Chrysoperla species (Neuroptera: Chrysopidae), with C. lucasina consistently outperforming C. carnea. Notably, C. lucasina was the only predator to attack N. viridula eggs, albeit at low levels. Against nymphal instars, third-instar C. lucasina larvae exhibited the highest predation, while second-instar C. lucasina often outperformed second-instar C. carnea and sometimes even matched the efficacy of third-instar C. carnea. All other predators showed little or no predation. In greenhouse cage trials, third-instar C. lucasina significantly reduced the survival of both first- and second-instar N. viridula nymphs under the structurally complex on-plant conditions. Across all assays, first-instar N. viridula nymphs were generally more vulnerable to predation than second-instar nymphs. These results identify C. lucasina as a promising candidate for augmentative biological control of N. viridula, warranting further evaluation under longer exposure periods, mixed-prey environments, and in combination with other biocontrol agents, such as egg parasitoids. Importantly, this study highlights how cryptic species within commercially used predators can differ markedly in efficacy, an underrecognized aspect of functional diversity in biological control.