Studies of a swollen shoot virus isolate from the Brong Ahafo Region of Ghana
1976
Ollennu, L.A.A.
The isolation of new cocoa swollen shoot disease virus with a bacilliform shape, the Nkrankwanta isolate, in the Brong Ahafo Region (Ghana) is reported. Its symptoms consist of leaf chlorotic flecking associated with the finer veins and diffuse vein clearing followed by defoliation, shoot die-back and tree death. Its thermostability (thermal inactivation point of between 50-55 deg C) is similar to the Kpeve isolate and slightly more stable than Kofi Pare isolate. It causes a big reduction in dry weight leaf area, leaf number, stem height and girth as well as die-back, necrosis of lateral roots and death of infected Amelonado cocoa seedlings. The virus is not readily available to the mealy bug as a vector hence the transmission rates are low. The vectors include Planoccoides njalensis (Laing), Ferrisia virgata (Cockerell), and Planococcus citri (Risso)
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