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VIRUS DISEASES OF CACAO IN WEST AFRICAL: II. CROSS‐IMMUNITY EXPERIMENTS WITH VIRUSES 1A, 1B AND 1C
Author(s) -
CROWDY S. H.,
POSNETTE A. F.
Publication year - 1947
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1947.tb06373.x
Subject(s) - theobroma , biology , inoculation , virus , virology , immunity , botany , horticulture , immunology , immune system
Experiments on cross‐immunity reactions between three viruses attacking Theobroma cacao L. on the Gold Coast are described. A field trial involving 3 acres of graft‐inoculated trees revealed some degree of protection afforded by Theobroma virus 1B against infection with virus 1A. The protection appeared to be more effective against insect inoculation than against graft transmission, being only temporary in the latter. Virus 1C (probably unrelated but not to be called Theobroma virus 2 until more evidence is available) conferred no protection against virus 1A. The latent periods for these viruses were calculated from this experiment, which also provided data on their effects on yield. Virus 1A reduced yield by 50% in the first year after inoculation and killed the trees in the second. Virus 1B had no appreciable effect on yield; virus 1C reduced yield by 50 % in the third year after inoculation but there was no further decline in the fourth. The rates of spread of these viruses were compared and significant differences demonstrated.