Back transmission of apple chlorotic leafspot virus (type strain) to apple and production of apple topworking disease symptoms in Maruba Kaido (Malus prunifolia Borkh. var. ringo Asami.

Apple chlorotic leafspot virus (CLSV) type strain isolated from an apple tree was back-transmitted to 8-day-old apple seedlings by rub-inoculation with partially purified and highly purified inoculum. The back-transmitted isolates induced typical apple topworking disease symptoms on a clone of Maruba Kaido (Malus prunifolia Borkh. var. ringo Asami) infected with other latent viruses (including the Maruba CLSV strain) as well as on a virus-free clone. The back-transmitted isolates induced symptoms identical to the parent isolate on a range of CLSV-sensitive indicator plants.