title: Direct plantlet inoculation with soil or insect-associated fungi may control cabbage root fly maggots.
abstract: A potential Delia radicum biological control strategy involving cauliflower plantlet inoculation with various fungi was investigated in a series of laboratory and glasshouse experiments. In addition to entomopathogenic fungi, fungi with a high rhizosphere competence and fungi with the ability to survive as saprotrophs in soil were tested. The following fungal species were evaluated in the experiments: Trichoderma atroviride, T. koningiopsis, T. gamsii, Beauveria bassiana, Metharhizium anisopliae, M. brunneum and Clonostachys solani. A commercial carbosulfan-based insecticide was used as a positive control. Additionally, two commercial products, one based on B. bassiana (Naturalis) and one on Bacillus thuringiensis (Delfin) were used as reference biocontrol agents. The aims were (i) to assess the pathogenicity of the selected fungal isolates to Delia radicum, (ii) to evaluate the fungal isolates' rhizosphere competence, with the emphasis on the persistence of the original inoculum on the growing roots, (iii) to assess possible endophytic plant tissue colonization, and (iv) to evaluate potential plant growth stimulating effects of the added inoculi. Significant pathogenicity of tested fungi against Delia radicum was confirmed in in vitro and glasshouse experiments. All tested fungi persisted on cauliflower rhizoplane. More importantly, the added fungi were found on thoroughly washed roots outside the original point of inoculation. This provided us with evidence that our tested fungi could be transferred via or grow with the elongating roots. In addition to colonizing the rhizoplane, some fungi were found inside the plant root or stem tissue, thus exhibiting endophytic characteristics. The importance of fungal ecology as a criterion in appropriate biological control agent selection is discussed.
authors.affiliation: Agricultural Institute of Slovenia, Hacquetova ulica 17, Ljubljana SI-1000, Slovenia; Zurich University of Applied Sciences, Campus Grueental, P.O. Box 335, Waedenswil CH-8820, Switzerland. Electronic address: jaka.razinger@kis.si.
authors.forename: Jaka
authors.initials: J
authors.lastname: Razinger
authors.affiliation: Zurich University of Applied Sciences, Campus Grueental, P.O. Box 335, Waedenswil CH-8820, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lutz
authors.affiliation: Agricultural Institute of Slovenia, Hacquetova ulica 17, Ljubljana SI-1000, Slovenia.
authors.forename: Hans-Josef
authors.initials: HJ
authors.lastname: Schroers
authors.affiliation: Zurich University of Applied Sciences, Campus Grueental, P.O. Box 335, Waedenswil CH-8820, Switzerland.
authors.forename: Marilena
authors.initials: M
authors.lastname: Palmisano
authors.affiliation: Zurich University of Applied Sciences, Campus Grueental, P.O. Box 335, Waedenswil CH-8820, Switzerland; Liebegg Agricultural Center, Liebegg 1, Graenichen CH-5722, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Wohler
authors.affiliation: Agricultural Institute of Slovenia, Hacquetova ulica 17, Ljubljana SI-1000, Slovenia.
authors.forename: Gregor
authors.initials: G
authors.lastname: Urek
authors.affiliation: Zurich University of Applied Sciences, Campus Grueental, P.O. Box 335, Waedenswil CH-8820, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Grunder
mesh_terms: D000818:Animals; D001937:Brassica / Q000382:microbiology*; D004175:Diptera / Q000382:microbiology*; D005658:Fungi; D007814:Larva / Q000382:microbiology*; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology
keywords: Biological control; Delia radicum; Diptera; Entomopathogenic fungi; Rhizosphere competence; Soil pest