Pathogenicity, Biology and Production of a new isolate of Heterorhabditis bacteriophora (Poinar, 1976) (Nematoda: Heterorhabditidae) from Argentina.

ACHINELLY, MARÍA FERNANDA; ELICECHE DAIANA; CAMINO NORA

Halifax

Congreso; 2011 International Congress on Invertebrate Pathology and Microbial Control & 44th Annual Meeting of the Society for Invertebrate Pathology; 2011

Society for Invertebrate Pathology

Entomopathogenic nematodes belonging to the Heterorhabditidae are lethal parasites to soil-dwelling insects. They are commonly used as biological control agents of insects in cryptic habitats. Here, we provide data from the first evaluation of the pathogenicity of a native nematode, Heterorhabditis bacteriophora strain VELI, isolated from organic gardens, in Villa Elisa, Buenos Aires province, Argentina. Ten Galleria mellonella (L.) larvae were exposed to the nematode at 15:1IJs/larva in Petri dishes (10 cm diameter) at 25°C. Six replicas with six repetitions were performed. Daily three replicates were observed and dead insects were dissected to record the mortality, parasitism and the nematode stage. In the other replicas, parasitized cadavers were placed in White traps to the emergence of the IJs. These results demonstrated the pathogenicity of H. bacteriophora causing between 70%-90% mortality. The nematode killed the insects 48 hs (57.14%) to 72 hs (42.85%) after contact. The parasitic period lasted between 10 to 14 days from the moment IJs entered the insect to the time when new IJs were formed, registering the highest number (42.1%) on day 12th. Emergence continued until 31-32 days. We observed two generations of nematodes, the first one with hermaphrodites (4-7 after the death of the larvae) and the second one with females and males (8-13 days). The number of IJs  also a detrimental effect on the weight of larvae. The study of the interaction between EPN and RPW could be crucial understanding the mode of action of EPN in the different instars and the reason for the response to different doses.