Occurrence of Natural Enemies ofSpodoptera frugiperda(Lepidoptera: Noctuidae) in Chihuahua, Mexico

Abstract

All instars of fall armyworm (FAW), Spodoptera frugiperda Smith & Abbot (Lepidoptera: Noctuidae), were collected in maize (corn) fields in 5 localities of the state of Chihuahua, Mexico, in 2014, with the main objectives of identifying its natural enemies and estimating the level of parasitism. Larvae were maintained under controlled conditions, fed with artificial diet, and observed daily until the emergence of parasitoids, until the appearance of mycosis, nematodes, or typical symptoms of baculoviral infection, or until they reached adulthood. Out of 5,870 larvae collected, 1,068 were attacked by natural enemies (parasitoids and entomopathogens), representing a total incidence of 18.2%. The incidence of parasitism by parasitoids was 8.1%, and parasitoids emerged from 5.8% of the larvae. The parasitoids found were: Chelonus insularis Cresson and Meteorus arizonensis Muesebeck (Hymenoptera: Braconidae); Campoletis sonorensis (Cameron), Campoletis flavicincta (Ashmead), Pristomerus sp. (Hymenoptera: Ichneumonidae); Euplectrus platyhypenae Howard (Hymenoptera: Eulophidae); and Lespesia sp. and Archytas marmoratus (Townsend) (Diptera: Tachinidae). Meteorus arizonensis and C. flavicincta were the most commonly encountered parasitoids, affecting 3% and 1.3% of the total collected larvae, respectively. Also, 2 species of entomopathogenic fungi were found: Metarhizium rileyi (Farl.) Kepler, S.A. Rehner & Humber comb. nov. (= Nomuraea rileyi [Farl.] Samson; Hypocreales: Clavicipitaceae) and Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae), with incidences of 8.6% and 0.65%, respectively. Forty-nine nucleopolyhedrovirus (Baculoviridae) isolates were obtained, corresponding to an incidence of 0.8%. Also, 0.07% of larvae were infected by entomopathogenic nematodes. In addition to the parasitoids and pathogens obtained, 34 specimens of the predator Podisus maculiventris (Say) (Hemiptera: Pentatomidae) were found during the surveys.