ISHS Acta Horticulturae 544: IV International Walnut Symposium
RELATIONSHIP BETWEEN EXTERNAL NECROSIS AND KERNEL |
| Authors: | J.M.S. Martins, A. Gonçalves, N. Neves |
| Keywords: | walnut blight, external necrosis and kernel spoilage, loss assessment |
| Abstract:
The relationship between external necrosis and internal symptoms was studied during two years in nuts of cv. Lara submitted to copper treatments. Intensity of disease in kernels was not significantly correlated with the area of external necrosis (severity). As for inci-dence, 90% or more (depending on treatments applied) of the nuts showed necrosis on the epicarp and mesocarp just before harvest, while kernel destruction amounted to less than 50%. Thus, it is not possible to predict the occurrence or extent of kernel damage by measuring the area of necrosis on the outer tissues. The presence of bacterial blight necro-sis around the pistil does not differ significantly from necroses over the rest of the fruit surface with respect to their correlation with kernel symptoms or fruit drop before matur-ity. These results seem to indicate that the transport of pathogenic bacteria on pollen grains does not play such a relevant role in the epidemiology of this disease as is gener-ally accepted. | |
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