Pest Management Systems and Insecticide Tolerance of Lacewings (Neuroptera: Chrysopidae)

Abstract

Lacewings (Neuroptera: Chrysopidae) are part of the beneficial fauna found in citrus orchards under both organic and conventional pest management. Due to their importance, knowledge about susceptibility of these predators to insecticides is a key element for their use as biological control agents. We studied the inter- and intraspecific susceptibility of the following lacewing species to bifenthrin, chlorpyrifos, and imidacloprid: Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae), Ceraeochrysa cubana (Hagen), Ceraeochrysa paraguaria (Navás), and Chrysoperla externa (Hagen). Different concentrations of these insecticides were sprayed on first instar larvae of these lacewing species from six orchards (three organic and three conventional), and LC50s were estimated. Development and reproduction of the most common lacewing, C. cincta, from both organic and conventional management systems were also studied. Lacewings from conventional management areas do not always have greater tolerance to insecticides. Chrysoperla externa was the most susceptible species to insecticides. Ceraeochrysa cincta displayed the highest LC50 and its populations from the conventional system showed lower egg hatching but shorter egg and larval developmental time. Adults collected from orchards managed conventionally lived longer, exhibited a higher population growth rate and a reduced doubling time. Ceraeochrysa cincta was the more tolerant species to insecticides better coping with systems that rely on chemical control as the main pest management tactic used.