A viable alternative to expansion is improvement of the existing acreage. Many factors influence yield, including disease, variety, nutritional status and soil type. Previous work has shown that, in New Jersey, Phytophthora cinnamomi is a nearly ubiquitous water borne fungus that is distributed through the irrigation systems . This pathogen infects and rots the plant roots resulting in reductions in plant biomass and productivity. Disease development occurs in areas with poor drainage and often results in plant death.
Chronic infections are often undetectable in the field.
Control strategies for PRR include improvement of soil drainage, followed by fungicide use. Early detection of root rot prone areas aids in disease management and helps decrease the time required for bed establishment. Little information is available on the pathogen effects on plant growth and yield loss and there has been no research describing loss due to factors such as reduction in bud set, or reduction in fruit size. Thus, the economic impact of this disease is poorly understood. Fairy ring is caused by the fungus Psilocybe agrariella.