Influence of temperature on pathogenicity of some entomopathogenic nematode isolates (Steinernema spp.) from Japan screened for ability to control some noctuid moth larvae

Abstract

Influence of temperature on pathogenicity of some entomopathogenic nematode isolates (Steinernema spp.) from Japan screened for ability to control some noctuid moth larvae 1,2Mutsuhiro Yoshida 3, Pathogenicity of indigenous steinernematids against some noctuid larvae was examined to screen candidates in a biological control program. First, 17 isolates from ten species (Steinernema feltiae, S. kraussei, S. kushidai, S. litorale, S. monticolum and five RFLP types) were screened for pathogenicity against the middle instar larvae of Peridoroma saucia, and S. feltiae and S. litorale were selected. Secondly, three isolates of S. feltiae and eight isolates of S. litorale were screened for pathogenicity against the middle instar larvae of Agrotis segetum, and S. feltiae HkEr36 and S. litorale IbKt142 were selected. Both isolates showed high pathogenicity at 25 and below, but reduced pathogenicity at 30 . Therefore, with the addition of a subtropical species S. abbasi collected after the second screening, the screened isolates were compared with an introduced nematode, S. carpocapsae All, for their pathogenicity against the late instar larvae of A. segetum and Spodoptera litura. The isolate S. litorale IbKt142 showed high pathogenicity between 7 and 25 , and caused significantly higher mortality of A. segetum at 7, 10 and 15 and S. litura at 7 and 10 than S. carpocapsae All did. Moreover, S. abbasi OnIr181 caused significantly higher mortality of A. segetum at 30 and 35 and S. litura at 35 than S. carpocapsae All did. Nematol. Res. 40 (2), 27-40 (2010).

Effectiveness of different entomopathogenic nematode species against the variegated cutworm, Peridroma saucia (Hubner) (Lepidoptera: Noctuidae)

“…The pathogenicity of 17 Japanese isolates of EPNs was tested against the middle instar larvae of P. saucia in a laboratory experiment at different temperatures. Three isolates belonging to S. feltiae caused 70% average mortality at 25°C which is similar to our study (Yoshida, 2010).…”

“…Increase in the time of exposure caused more mortality to last instar P. saucia larvae by all the tested nematode species (Table 1). Similar studies have been carried out to evaluate the effectiveness of EPNs against P. saucia larvae where it was revealed that EPNs have great potential for the management of P. saucia larvae (Yoshida, 2010;Morris and Converse, 2012). The pathogenicity of steirnematid and heterorhabditid nematode species against P. saucia larvae was variable in previous studies.…”

“…Due to the high tolerance of VCW, repeated applications of conventional insecticides are widely used. Development of resistance and concerns over the destructive effects of chemicals to environmental and human safety have accelerated the development of alternative control methods for this pest (Yoshida, 2010).…”