Studies on resistance and tolerance to cocoa viruses in Ghana

SUMMARY Cuttings of twenty‐seven cocoa selections were infested with mealybugs ( Planococcus njalensis ) which had fed on plants infected with the New Juaben strain of cocoa swollen shoot virus. Susceptibility to infection with CSSV seemed to vary, and in general those selections which had appeared relatively resistant in earlier studies again appeared resistant. There were great differences in reaction to infection, clones from Scavina × unknown progenies being least affected while various other Amazon selections, particularly some from Iquitos × unknown and Nanay × Iquitos progenies, were also very tolerant. Some local Trinitario selections displayed a measure of tolerance. The tolerance results were similar to those previously obtained in Ghana with the same virus and using beans or seedlings, and also to those obtained in field trials and with budded material infected with Nigerian virus isolates.