Aphicidal potential and virulence of Lecanicillium fungi from Argentina

SAAR K.; TORNESELLO, J.; MANFRINO R. ; GARCIA, J.J.; SCHUSTER, C.; LOPEZ LASTRA, C.C.; LECLERQUE, A.

Tours

Congreso; International Congress on Invertebrate Pathology and Microbial Control, 49 th Annual Meeting of the Society for Invertebrate Pathology; Tours, Francia 2016.Update of knowledge about Leptolegnia chapmanii as an agent of biological control of mosquito Aedes; 2016

Mitosporic fungi of the genus Lecanicillium (Ascomycota; Hypocreales) are of particular interest as biological control agents for phloem-suckingplant pests including aphids. Bioprospection for these fungi in Argentina has given rise to a set of single-spore derived Lecanicillium strains isolatedfrom a wide range of original hosts. For species-level characterization of Lecanicillium isolates, five genetic markers comprising one mitochondrial(NMS) and two nuclear (ITS, IGS) ribosomal RNA operon together with one mitochondrial (nad1) and one nuclear (ef1 a) protein-encodingsequences, has been employed. The aggregated information from these markers indicates that fungal isolates from Argentina mainly, but notexclusively belong to the Lecanicillium core species. Moreover, Lecanicillium strains has been investigated for fungicide sensitivity. Between strainsdifferences in susceptibilities have been found to be important and not necessarily in line with systematics, making careful determination ofsensitivity to agriculturally used fungicides an important criterion of biocontrol agent selection. However, the fungicidal polyketide compoundsoraphen has been found of outstanding activity against a wide variety of isolates from all species investigated. On the basis of these results, somestrains have been selected for virulence bioassays against Brevicoryne brassicae. For each replicate 15 apterous adults were used. The applied dosewas 1.107 conidia/ml and the application method was spray. After treated, aphids were placed on each seedling and mortality was controlledduring the 10 days after application. The strains that caused the highest and the lower mortality were 155 (66.6%) and 182 (31%), respectively.