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The effect of sprays of thiophanate–methyl on cane diseases and yield in red raspberry, with particular reference to cane blight ( Leptosphaeria coniothyrium )
Author(s) -
WILLIAMSON B.,
HARGREAVES A. J.
Publication year - 1981
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.1744-7348.1981.tb03009.x
Subject(s) - cane , biology , botrytis , blight , girdling , blowing a raspberry , horticulture , botrytis cinerea , agronomy , inoculation , yield (engineering) , biochemistry , sugar , materials science , metallurgy
SUMMARY Spur blight ( Didymella applanata ), cane botrytis ( Botrytis cinerea ) and cane blight ( Leptosphaeria coniothyrium ) were studied in two consecutive seasons in unsprayed raspberries and in plots sprayed with thiophanate‐methyl in the first season alone, (a) twice pre‐harvest, (b) twice post‐harvest, or (c) twice pre‐ plus twice post‐harvest. Pre‐harvest, but not post‐harvest sprays, gave moderate control of both spur blight and cane botrytis; both diseases occurred mainly on the lower halves of canes, the latter being the less common. Cane blight occurred at the base of canes where they were wounded by old cane stubs. In the first year it was severe; 37% of canes died before harvest in the unsprayed plots. The three spray programmes all decreased cane death due to cane blight and they all increased yield by c. 45% even in those plots sprayed post‐harvest where spur blight was severe and not controlled. Clearly this last disease, despite its high incidence, had no effect on potential yield in this experiment. In the second year cane blight was common but less severe and the incidence of its lesions was reduced similarly by all programmes, but only 4% of canes died in control plots. Analysis of the potential yield and the sizes of lesions caused by L. coniothyrium in canes inoculated at fortnightly intervals in the previous year showed that potential yield loss occurred only when lesions girdled canes. A bimodal distribution in the lesion sizes, measured by length or girdling, indicated some endogenous control of lesion development which might explain the marked differences in the effect of cane blight on potential yield in two seasons.