TRANSMISSION OF EUROPEAN STONE FRUIT YELLOWS PHYTOPLASMA BY CACOPSYLLA PRUNI
L. Carraro, R. Osler, N. Loi, P. Ermacora, E. Refatti
Experimental transmission of European stone fruit yellows phytoplasma to Japanese plum cv. ‘Ozark Premier’ was achieved using Cacopsylla pruni, caught in the field or raised on infected plants under controlled conditions. Using different groups of infectious psyllas, 89% of the inoculated test plants were infected. Both nymphs and adults were able to transmit. Insects exposed to test plants immediately after capture or raised in cages transmitted the disease. After an incubation period of 4-5 months the first test plants showed typical symptoms. Sources of inoculum, test plants and vectors were examined by PCR for the presence of phytoplasmas. Following digestion of the amplification products with restriction enzymes, isolates from plants and insects showed the same restriction profiles. Interestingly, pear decline and European stone fruit yellows, members of the apple proliferation cluster, are both transmitted by Cacopsylla spp.