Some properties of cocoa swollen-shoot virus

SUMMARY: Partially purified preparations of the Kofi Pare isolate of cocoa swollen-shoot virus (CSSV) were usually inactivated after 10 min. at 50°, but not after 10 min. at 45°. Infectivity of freshly made preparations was greatly lessened by diluting 1/10, and lost at 1/100. The infectivity of preparations increased after storage for 24 hr; after 96 hr infectivity was retained at 0--4° but soon lost at 25°. The virus survived freezing in vitro and, with some loss of infectivity, freezing in leaves and storage in leaves dried over aluminium oxide. Infective material was precipitated from dilute extracts by half saturation with ammonium sulphate at 25°; it appeared to be equally stable over the range pH 6 to pH 8. Preparations of the symptomatologically distinct Kofi Pare, Mampong, Dawa, Nsaba and Bosomuoso isolates all contained similar rod-shaped particles of size about 121 x 28 m/μ.