Potatoes are a vegetatively propagated crop, and many disease organisms including several viruses and a viroid are disseminated in tubers. The important role that tubers play in virus spread is recognized by the strict requirements for foundation...

organisms. Epidemiology and disease development The following comments address pepper Phytophthora blight (P. capsict), and in general also apply for diseases of crops listed in the table. The fungus occurs naturally in most soils and can infect Fig. 5...
(two-tailed) motile zoospores. These spores produce germ tubes that penetrate plant tissue. The cycle is repeated with the production of more sporangiophores and sporangia. When the humidity is high, the sporangia can survive for long periods. During...

as disease appears, using a fixed copper plus maneb 80 WP or maneb plus zinc product to prevent secondary spread of the bacterium. The combination of copper and maneb has been shown to be more effective in controlling strains of the organism that are either...
of lesions can occur on leaf margins and tips where moisture accumulates (fig . 1). Eventually the leaves yellow and drop off, increasing the chance for sunscald (fig. 2). Spots on fruits become raised, scablike areas that make the product unmarketable (fig...