Invasive Species Compendium

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Lewia chlamidosporiformans, a mycoherbicide for control of Euphorbia heterophylla: isolate selection and mass production.


The potential of the fungus Lewia chlamidosporiformans Vieira and Barreto as a biological control agent for wild poinsettia, Euphorbia heterophylla L., a noxious invader of soybean fields in Brazil, is being assessed. One isolate was selected from nine that were tested as being the most aggressive to a series of wild poinsettia populations (including one known to be herbicide-resistant). The biphasic technique was investigated as an option for mass production of conidia of L. chlamidosporiformans. This method involves the production of mycelia in liquid culture that are later blended and poured into trays containing a solid medium and incubated under a specific light regime until conidia form. After 3 days, conidia are harvested once per day by pouring sterile water over the surface of the colonized medium and scraping the surface with a rubber spatula. A semi-synthetic liquid medium (with a sucrose and asparagin base) was selected as the best for the first phase of growth. A vegetable brothagar medium supplemented with CaCO3 was the best solid medium for fungal growth and sporulation in the second phase.