Existing crop monitoring programs determine the incidence and
distribution of plant diseases and pathogens and assess the damage
caused within a crop production region. These programs have traditionally
used observed or predicted disease and pathogen data
and environmental information to prescribe management practices
that minimize crop loss (3,69). Monitoring programs are especially
important for crops with broad geographic distribution or for diseases
that can cause rapid and great economic losses. Successful
monitoring programs have been developed for several plant diseases,
including downy mildew of cucurbits, Fusarium head blight
of wheat, potato late blight, and rusts of cereal crops