THE SANITARY STATUS OF STONE FRUIT SPECIES IN APULIA

An account is given of the results of extended of investigations carried out in the main stone fruit growing areas of Apulia. The aim was to assess the sanitary condition of the crops and to identify the prevailing virus and virus-like diseases. The studies were based on (i) field surveys for the observation of symptoms; (ii) mechanical transmissions on herbaceous hosts for the isolation of viruses; (iii) graft-transmissions on to woody indicators for detection of virus-like diseases and (iv) ELISA and IEM tests for virus identification.

Symptoms were observed in all species such as: chlorotic, yellowish spots and/or line patterns, reduced growth and deformation of the leaves, deformation and irregular maturation of fruits, pitting of stems.

Almond and cherry had very high infection rates (80% and 65%, respectively), whereas for the other species the level of infection ranged between 25% (plum) and 35–36% (peach and apricot).

Prunus necrotic ringspot (PNRSV), prune dwarf (PDV) and apple mosaic (ApMV) ilarviruses and apple chlorotic leaf spot (ACLSV) trichovirus were common in all species, with ApMV prevailing in almond (45%), PDV in cherry (75%), PNRSV in peach and plum (55% and 33%, respectively) and ACLSV in apricot (33%). Plum pox (PPV) potyvirus was detected in some young apricot and plum plantings.

Through sanitary selection and sanitation by heat therapy, 160 different "virus-tested" cultivars and/or clones (41 peaches, 22 cherries, 17 apricots, 23 plums and 57 of almonds) and 10 different rootstocks were obtained which have now entered the regional certification programme.