Geographic and Seasonal Distribution

Polioviruses are found worldwide, although less commonly in areas where hygiene is good, and inactivated rather than live attenuated vaccines are used. Isolates are thus rare in countries such as Sweden, but common in developing countries or in and Mandahar CL (eds), Plant Viruses, Vol. II, Pathology, p.l. Boca Raton, FL: CRC Press. Bawden FC (1964) Plant Viruses and Virus Diseases, 4th edn. New York: The Ronald Press. Bos L (1978) Symptoms of Virus Diseases in Plants, 3rd edn.

Wageningen, The Netherlands: Pudoc. Heathcote GD (1986) Virus yellows of sugar beet. In: McLean GD, Garrett RG and Ruesink WR (eds) Plant

Virus Epidemics. Monitoring, Modelling and Predicting Outbreaks, p. 399. Sydney: Academic Press.

Matthews REF (1991) Plant Virology, 3rd edn. New York: Academic Press.

Zadoks JC (1985) On the conceptual basis of crop loss assessment: the threshold theory. Annu. Rev. Phyto-pathol. 23: 455.

0 0

Post a comment