Spread of cocoa swollen shoot virus to cacao (Theobroma cacao L.) plantings in Ghana

Between 1973 and 1979, a number of cacao (Theobroma cacao L.) varieties developed at the Cocoa Research Institute of Ghana and thought to have resistance or tolerance to cocoa swollen shoot virus (CSSV) were evaluated at 128 sites on farmers' holdings. In 1997, inspections were carried out at 6 of these sites in the Ashanti Region (AR) and 17 sites in the Eastern Region (ER) to study the extent of further spread of CSSV after the farms were returned by the Government to the farmers in 1988. Infection recurred at two sites in the AR after 1988 while in the ER there was no further infection at six of the sites. Three other sites in the ER were most affected, namely, Jumapo with a re-infection of 43.6%, Tafo South with a rate of 31.2%, and Owura Twum with a rate of 23.2%. Of the remaining eight sites in the ER, five sites showed 1.0-10.9% CSSV infection, while the other three sites had <1% CSSV infection. The results are discussed in relation to the control of swollen shoot disease in the worst-affected areas of the ER where control is currently limited to new plantings and on farmers' request.