Compatibility of entomopathogenic nematodes with fipronil

Department of Animal Biology, Vegetal Biology and Ecology, Autonomous University of Barcelona, Cerdanyola del Vallès, Catalonia, Spain
Journal of Helminthology (Impact Factor: 1.3). 01/2006; 79(4):333-7. DOI: 10.1079/JOH2005294
Source: PubMed

ABSTRACT The survival and infectivity of infective juveniles (IJs) of three species of entomopathogenic nematodes, Steinernema carpocapsae Weiser, S. arenarium (Artyukhovsky) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), were determined after exposure to different concentrations (250, 500, 1000 and 2000 ppm) of fipronil, an insecticide acting on the GABA receptors to block the chloride channel. Heterorhabditis bacteriophora was very tolerant to all concentrations of fipronil, with the highest mortality of 17% being observed at 2000 ppm of fipronil after 72 h exposure. Steinernema carpocapsae showed a similar response, with the highest mortality of 11.25% of IJs being observed after 72 h exposure to 2000 ppm of fipronil. Steinernema arenarium was, however, more sensitive to fipronil, and at 2000 ppm mortality rates of 94.6% and 100% were observed after 24 and 72 h, respectively. Fipronil had negligible effects on the infectivity of the three nematode species tested. The IJs which survive exposure to all concentrations of fipronil tested can infect and reproduce in Galleria larvae. The moderate effects on entomopathogenic nematodes of a lower fipronil concentration (250 ppm) and the field rates (12-60 ppm) of fipronil used as insecticide, suggest that direct mixing of entomopathogenic nematodes and fipronil at field rates is a viable integrated pest management option.

Download full-text


Available from: Fernando Garcia del Pino, Oct 31, 2014
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In South Africa, the most common method of mealybug control has been the use of chemical insecticides. Entomopathogenic nematodes (EPNs) of the of the families Heterorhabditidae and Steinernematidae potentially can be used within an integrated pest management scheme to control Planococcus ficus, the vine mealybug, which occurs on all parts of grapevine, including the roots. When Steinernema yirgalemense was applied to the soil of two vineyards with P. ficus, contained in pierced Eppendorf tubes, buried at a depth of 15 cm in the soil, mortalities of up to 50% were obtained after 48 h. The persistence of S. yirgalemense, measured using codling moth larval mortality was found to be zero in one vineyard, while in the other it was 70%, 12 weeks after application. Tests were conducted to establish the production of scavenger deterrent factors by H. zealandica and S. yirgalemense. Of the cadavers that were presented six days after nematode infection, 49% of the H. zealandica- and 60% of the S. yirgalemense-infected cadavers were left intact. Olfactometry tests indicated a significant difference concerning the number of S. yirgalemense infective juveniles (IJs) that were attracted to damaged Vitis vinifera roots and P. ficus, indicating active movement of the IJs and the attractive ability of organic compounds produced by the roots. This study shows that EPNs, and specifically S. yirgalemense, have promising potential as biological control agents for the control of P. ficus soil populations, and investigates some influential factors affecting EPNs as biocontrol agents in the agro-ecosystem.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 ENTONEM® (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 ENTONEM® 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.
    Biocontrol Science and Technology 01/2008; 18(1):101-108. DOI:10.1080/09583150701684267 · 0.73 Impact Factor
  • Source