ABSTRACT
Necrovirus is a concocted name for a group that was originally named the tobacco necrosis virus group. At one time the ICTV assigned the A strain of tobacco necrosis virus (TNV) to the group as the type member, the D strain of TNV as a member, and cucumber necrosis virus (CNV) as either a probable member or a possible member. Estimates of TNV particle diameter range from 20 to 52 nm. Effects of pH on TNV particles stained in phosphotungstate (PTA) were studied by Finlay and Teakle. They found little change in particles stained in PTA at pH 3 or 4, slight degradation at pH 5, and severe degradation at pH 6 or 7. Carnation yellow stripe virus (CYSV) is a virus whose position in classification is currently undecided; it may be a definitive necrovirus, or it may be a strain of TNV.
