ISHS Acta Horticulturae 193: XIII International Symposium on Fruit Tree Virus Diseases
POSSIBLE TRANSMISSION AND NATURAL SPREAD OF FRECKLE PIT AND/OR AN ALFALFA GREENING-LIKE DISORDER OF 'ANJOU' PEARS |
| Authors: | C.L. Parish, J.T. Raese |
| Abstract:
'Anjou' pear trees were inoculated with 11 different sources of freckle pit and/or alfalfa greening. Two years after inoculation, the fruit near the inoculation sites on 2 trees exhibited pits on the calyx-end. The underlying tissue of the affected fruit contained a network of green strands. The next year, affected fruit appeared throughout 9 of the 11 inoculated trees. The affected fruit contained pits on the calyx-end with a network of green strands in the underlying tissue. A few of the pitted fruit also had superficial cork. Four years after inoculation, the symptoms consisted of small pits, a network of green strands, and superficial cork. No green streaks or blotches were observed near the stem-end of the fruit. The uninoculated check trees remained symptomless. Five years after inoculation, all the inoculated trees expressed symptoms. The affected fruit exhibited all of the symptoms expressed previously; plus longitudinal green streaks, specks, or blotches were noticed for the first time. It is not clear if the longitudinal green streaks and blotches observed were part of the symptoms induced by the transmitted agent. In selected orchards, the same 'Anjou' pear trees were surveyed for pitted fruit for 4 years; the number of trees expressing symptoms increased nearly 50% each year. This possibly suggests natural spread was occurring. | |
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