Abstract
C. malvarum was evaluated as a bioherbicide for prickly sida control in agronomic crops. Of 38 plant species tested, only hollyhock (Althaea rosea) and prickly sida (Sida spinosa) were susceptible. In growth chamber experiments, disease symptoms on prickly sida seedlings were severe after single and multiple dew periods of 16 h. In small field plot studies, inoculations with an aqueous suspension of 4 .times. 106 conidia/ml applied at 378 l/ha killed 84-95% of the prickly sida plants after 3 wk.