Abstract

CORTEZ-MONDACA, Edgardo  and  MACIAS-CERVANTES, Jaime. Natural parasitism of diamondback moth Plutella xylostella L. in canola (Brassica napus L.), in northern Sinaloa, México. Agrociencia [online]. 2007, vol.41, n.3, pp.347-354. ISSN 2521-9766.

The diamondback moth (DBM) (Plutella xylostella L. (Lepidoptera: Plutellidae) is the most important pest of crucifers. It severely reduces harvest yield and quality and easily develops populations resistant to synthetic and biological insecticides that are used for its control. This study was conducted in the INIFAP Valle del Fuerte experimental station in Juan José Ríos, Sinaloa, México in canola Brassica napus L. var. napus (Brassicaceae) where insecticides were not applied. Diamondback moth (DBM) larvae and pupae and its parasitoids were obtained from leaves collected during the stage of pod formation and filling. The parasitoids were identified by taxonomy specialists. Natural parasitism, percentage of DBM mortality from unknown causes, and the host-parasitoid density-dependent ratio were determined. The parasitoids obtained were Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae), Cotesia sp. (Hymenoptera: Braconidae), and Conura sp (Hymenoptera:Chalcididae). D. insulare exhibited 25.0 to 80% parasitism (average 49.5%); Cotesia sp. between 0.0 and 75.0% (average 23.1%), and Conura sp. between 0.0 and 20% (average 3.2%). D. insulare had a close density-dependent relationship with the host (R2=0.85).

Keywords : Brassica spp.; Conura sp.; Cotesia sp.; Diadegma insulare; Plutella xylostella; density-dependent ratio..