Research Summary Abstract
From 2004 to 2012, fenamidone (FenStop, FenStar) was screened through the IR-4 Program as drench or foliar applications for effacay against nine Phytophthora species causing root rots and stem/leaf blights (P. cactorum, P. cinnamomi, P. citricola, P. cryptogea, P. drechsleri, P. nicotianae/parasitica, P. ramorum, P. syringae, and P. tropicalis), five Pythium species (P. aphanadermatum, P. dissotocum, P. irregulare, P. ultimum, and P. vipa), and two downy mildews (coleus, snapdragon). Efficacy ranged from highly effect to similar to nontreated inoculated controls depending on pathogen, host, and level of disease pressure. Based on findings it is recommended the following specific diseases be added to fenamidone labels: Coleus downy mildew, Phytophthora cryptogea, Phytophthora nicotianae, Phytophthora ramorum, Phytophthora cinnamomi, Pythium aphanadermatum, Pythium mamillatum, Pythium ultimum, and Snapdragon downy mildew. Currently, the FenStop/FenStar label is limited to greenhouse use. It is recommended this be expanded to include outdoor use patterns.