Comparative study of the effect of selected agrochemical products on Steinernema feltiae (Rhabditida: Steinernematidae)
Titel:
Comparative study of the effect of selected agrochemical products on Steinernema feltiae (Rhabditida: Steinernematidae)
Auteur:
Gutierrez, Carmen Campos-Herrera, Raquel Jimenez, Jesus
Verschenen in:
Biocontrol science and technology
Paginering:
Jaargang 18 (2008) nr. 1 pagina's 101-108
Jaar:
2008
Inhoud:
The effect of three neurotoxic insecticides, three photosynthetic inhibitor herbicides and three enzymatic inhibitor herbicides on infective juveniles (IJs) of Steinernema feltiae Rioja (native) and ENTONEMĀ® (commercial) strains were evaluated after a 48-h exposure at field tank concentrations and overnight treatment in mQ-water, using Spodoptera littoralis as target. Nematode survival was not affected by acetyl-cholinesterase inhibitors chlorpyrifos and pirimicarb, although chlorpyrifos seriously reduced their virulence. Both nematode strains showed differential sensitivity to cypermethrin, which affects the sodium channels of the nerve membrane, with the ENTONEMĀ® strain being more tolerant than Rioja strain. However, these chemicals showed a strong sublethal effect on the nematode reproductive potential, limiting seriously their possible recycling in the field. Herbicides showed differential toxic effects on nematode survival. The commercial strain was tolerant to enzymatic inhibitor herbicides, whereas tribenuron and chlorsulfuron reduced Rioja strain survival. However, photosynthetic inhibitor herbicides severely affected survival of both nematode strains, with the Rioja strain being more sensitive. Sublethal effects on both nematode strains were observed only after exposition to terbutryn+chlortoluron+triasulfuron, increasing the time to kill insect larvae. These results are useful to optimize EPN dosages and to estimate their field recycling.