Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/13/2015
Publication Date: 8/13/2015
Citation: Weiler, L., Rooney, A.P., Behle, R.W., Strickman, D.A. 2015. Characterization of Tolypocladium cylindrosporum (Hypocreales: Ophiocordycipitaceae)and its effectiveness in infecting Aedes aegypti eggs (Diptera: Culicidae). Meeting Abstract.
Technical Abstract: Availability of an effective egg-targeting system would allow for the control of a much greater portion of mosquito populations, because after emergence adults disperse away from egg-laying sites. Consequently, eggs form a reservoir of individuals highly susceptible to control measures. The purpose of this study was to evaluate the potential of the fungus Tolyplocladium cylindrosporum as a control agent for the mosquito Aedes aegypti. Morphological characterization of T. cylindrosporum IBT 41712 was conducted and pathogenic activity of the fungus against A. aegypti eggs was evaluated. Fungal growth at different temperatures, conidia germination and sporulation on solid media was observed using light microscopy and scanning electron microscopy. The fungus formed white colonies turning creamy white when mature, and sporulation occurred after 8-10 days of incubation. The mycelia bore flask-shaped or swollen conidiophores producing smooth-walled, single-celled conidia that are oblong and cylindrical in shape when mature. Conidia had 96-98% germination after 10 days incubation and appeared to vary in size, ranging from 1µm to 2.5µm long. The optimum temperature for growth was 28 deg C, with a maximum mean radial growth rate of 1.1 ± 0.02 mm/day. There was no fungal growth observed at 33, 37 or 40 deg C. However, growth was observed at 4, and 12 deg C, albeit much more slowly than at room temperature or optimal levels. Significant reduction in larval hatch was observed for fungus treated eggs with significantly fewer larvae surviving (20%) at 14 days post treatment compared with those surviving in the control (93%).