Irregular periderm formation along the cane is a good symptom of Pierce's disease.
Jay W, Pscheidt, 2002.
Grape vines with Pierce's disease show general water stress with marginal necrosis on the leaves.
Jay W, Pscheidt, 2002.
Cause Urocystis trillii, a fungus reported from Oregon and Idaho but considered a rare disease. This fungus is soilborne and infects plants as they emerge through the soil.
Cause The soilborne fungi, Pseudopyrenochaeta lycopersici and P. terrestris, that survive in infected tomato root debris as well as durable microsclerotia that can persist in soil for years. These fungi may also infect eggplant and pepper while melon, squash, spinach, and safflower may also be hosts. Temperatures between 59°F and 68°F are optimum for disease development. The fungi are slow growing and difficult to isolate from infected plant roots.