STUDIES ON FRUIT TREE VIRUSES IN URUGUAY

1. Introduction and propagation of the woody indicator plants recommended to test fruit trees;
2. Testing the collection of varieties and rootstocks of the institute by DAS-ELISA in 1992 and 1993. It showed that some of the stone fruits were infected with PNRSV, PDV, and CLSV (alone or combined) and some of the pome fruits with ApMV and CLSV.
3. Identification of the viruses serologically detected. Mechanical transmission to herbaceous indicator plants was obtained with PNRSV to cucumber (cv. Marketmore 76), squash (cv. Butternut), Chenopodium quinoa L., and Vinca rosea L., with PDV to cucumber and squash, ApMV to cucumber and CLSV positive samples to C. quinoa. Virus particles were observed by electron microscopy in cucumber plants mechanically infected with PNRSV positive samples. A thermal inactivation point that ranged between 55–60°C; and a longevity in vitro of more than 18 hours for PNRS were determined. CLSV and PDV will be further studied.
4. Indexing of plum and apple varieties and rootstocks with woody indicator plants. Even though results are preliminary, some virus symptoms were observed.
5. PNRSV infection was surveyed in nine commercial orchards (six varieties, 90 samples), its distribution depended on the variety involved. A total of 350 seedlings were tested in two commercial nurseries, 6–30% and 11–53% of seedlings were infected. At the experiment field, 35% of the 43 rootstock mother plants (grown from seed) were infected with PNRSV and a 5–14% of PNRSV seed transmission was obtained testing the 270 seedlings obtained from their seeds.

Download Adobe Acrobat Reader (free software to read PDF files)