First report of potato spindle tuber viroid in avocado
Though avocado (Persea americana) is an important crop in tropical areas, little is known about its virus and virus-like diseases. However during recent studies, avocado trees growing at several locations in Peru have been shown to be infected by potato spindle tuber viroid (PSTVd - EPPO A2 quarantine pest), by using nucleic acid spot hybridization assays. PSTVd infections were often latent, but some trees coinfected with avocado sunblotch viroid showed symptoms, characterized by bunchiness of the inflorescence, decreasing both fruit size and number, and eventually decline and death. The authors noted that in Peru, potatoes and avocados are often inter-cropped, and possible means of transfer between the two plants species are discussed (insect-mediated transfer of viruses between genetically incompatible species via virus-infected pollen, although rare is known to occur; transmission by nematodes such as Meloidogyne incognita could be a possibility). They stressed that further studies are necessary to investigate the possible role of interactions between PSTVd and avocado sunblotch viroid. This is the first report of PSTVd from a natural host other than potato (Solanum tuberosum).
Sources
Querci, M.; Owens, R.A.; Vargas, C. Salazar, L.F. (1995) Detection of potato spindle tuber viroid in avocado growing in Peru.
Plant Disease, 79(2), 196-202.