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...

, and the production of unmarketable fruit. Early recognition of the disease, especially in greenhouse crops, is essential if the disease is to be contained. The organism is seedborne and can survive for short periods in soil, greenhouse structures, and equipment...
organism into transplant production fields in southern Georgia originated on commercial seed. If seeds are harvested by either the acetic acid extraction method or by the fermentation process, the threat of seedborne inoculum is greatly reduced...

Viruses are the most common causes of diseases affecting cucurbits in New York. These diseases result in losses through reduction in growth and yield and are responsible for distortion and mottling of fruit , making the product unmarketable. A...

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...

in living host cells. Its vegetative phase consists of a multinucleate mass of protoplasm lacking a cell wall (plasmodium or slime mold). Although the organism primarily attacks members of the Cruciferae, the intensity of disease caused on different crops...
(see "Host Range") varies. The organism also exists as many specialized forms or races, the variation in plant resistance and ability to survive in different areas being explained thereby. Symptoms Clubroot may develop extensively on plant roots before...

) , Colletotrichum can cause severe rotting of below-ground plant parts and early plant decline leading to discolored tubers and reduce~ yields. The same black dot organism causes anthracnose or npe-fru1t disease of tomato, and can occur on other solanaceous crops...
, the organism does not penetrate intact tuber skin, but can grow and sporulate on damaged tissue. This limited growth, however, does not appear to provide entry sites for secondary fungal or bacterial invaders in stored tubers. In a three-month greenhouse test...

rot develops slowly and may not be severe until quite late into the storage period. This decay may allow the entry of secondary organisms such as Fusarium fungi and soft rot bacteria. �CONTROL The following measures will help prevent the occurrence...
. Surface tubers infected by conidia washed from leaves. ~,'~'~:~~"~:,~~:~~,-'".~"~~~~"'~",~",~~~ ~~~~~' ~~"~ "Target" spots Early Blight Disease Cycle Adapted in part from North Dakota State University Extension Bulletin 26, 1976, 'Potato Production...

was attributed to a physiological disorder; evidence of other workers in the United States supports this conclusion. Fungal organisms such as Botrytis, Alternaria, and Rhizoctonia may cause spotting and speckling of the outer leaves of cabbage heads...
and production fields. This should be coupled with early aphid control on the crop and bordering areas. Quantity discount available. Cooperative Extension, New York State College of Agriculture and Life Sciences, New York State College of Human Ecology, and New...

activities, and may be present in tobacco products. The virus is not spread by insects commonly occurring in the greenhouse or field. The symptoms in tomato vary greatly in intensity depending upon the variety, virus strain, time of infection, light intensity...
by this mycoplasmalike organism (fig. 8), rendering the plant incapable of setting normal fruit. Leafhoppers are generally not difficult to control in temperate climates; thus, vector control should reduce the incidence of this disease. Quantity discount available...