Ecology and biodiversity of broad bean wilt virus in Northern Italy.

Epidemiological investigations were made in northern Italy to check the role of wild plantain (Plantago lanceolata) and of pokeweed (Phytolaccca americana)a s reservoirs of broad bean wilt virus (BBWV). BBWV was consistently isolated from plantain plants showing ring spot symptoms, and froin three pokeweed plants with symptoins ranging from rnild to severe mottle. Four plantain isolates and two pokeweed isolates were cornpared with BBWV-I, BBWV-II by serology and host plant reactions. Two virus isolaies from plantain and one from pokeweed were serologically indistinguishable from BBWV-I, while two other plantain isolates differed slightly from a typical BBWV-I isolate. The second isolate from pokeweed differed serologicaliy fiom both BBWV-I and BBWV-II, from patchouli mild mosaic virus and frorn lamium mild inosaic virus. The role of plantain in the ecology of BBWV was thus confirmed also in northern Italy. Pokeweed is a new natural host of BBWV. Both species may play an important role in the ecology and differentiation of the virus, being able to harbour different isolates.