Not available – first paragraph follows: Root rots caused by species of Phytophthora are economically important diseases affecting a wide range of agricultural and ornamental crops. Although diseases caused by these fungi can sometimes be suppressed by fungicide treatments or use of resistant cultivare, in many situations they cannot be effectively controlled. These difficulties have prompted considerable research into conditions favoring the survival, reproduction, and spread of Phytophthora spp. in soil and their infection of plant roots.