Submitted to: International Weed Control Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2004
Publication Date: September 1, 2004
Citation: Laurent, N., Gras, S., Quimby Jr, P.C., Widmer, T.L. 2004. Formulation of phoma exigua, potential biocontrol agent against centaurea solstitialis. 12th International Conference on Weed Biology, Dijon, France pp.399-406. INRA, Dijon, France.
The fungus Phoma exigua is being investigated as a potential biocontrol agent against the invasive weed Centaurea solstitialis. Methods for formulating and storing are needed for eventual field applications. In this study, a method of formulation was tested with pellets prepared in 1% sodium alginate. The pellets were subsquently dried for 1 hour through a Fluid-Bed Dryer or stored in sucrose and tested for survival and pathogenicity. Pellets stored at '20°C, 4°C, and room temperature had 100% survival after 1 month tested regardless of the fungal growth media or storage preparation. Pellets had a low survival at 45°C after 3 days under certain storage preparations. Detached C. solstitialis leaves were almost 100% necrotic after 10 days when exposed to a pellet of P. exigua prepared with the Fluid-Bed Dryer. Pellets stored in sucrose or sucrose plus 1% pectin showed slightly less necrosis except when the fungus was grown in medium containing 0.1% pectin where the necrosis was below 60%. Pellets survived 100% in soil under natural field conditions when buried 2.5 cm for 3 months. Pellet survival was reduced to 60% when buried 5 cm for 3 months.