Since then, it has been found to be in young ash trees plants in several plant nurseries and is now known to be in over 100 plant nursery and woodland sites, mainly in eastern England.
Ers hynny, mae wedi’i ddarganfod mewn coed ifanc mewn sawl meithrinfa ac erbyn hyn, fe’i cafwyd mewn mwy na 100 o feithrinfeydd a choedlannau, yn bennaf yn nwyrain Lloegr.