Progress with direct bark inoculation for White Pine blister rust.

Describes tests in which entire rings of bark containing active Cronartium ribicola mycelium were transferred from cankered to healthy 6- to 9-year Pinus strobus stems. Out of 25 such inoculations, 14 transmitted the disease; 7 trees died through graft failure where bands were taken from the oldest portion of a canker; and in 4 cases the disease did not spread and symptoms disappeared from the grafted band. As infection was evident on all successful inoculations within a year after grafting, the method shows considerable superiority over other methods in time required to determine resistance. KEYWORDS: Blister rust inoculations \ plant diseases \ trees \ Fungi artificial inoculation \ fungal diseases \ Pinus strobus \ diseases \ blister rust \ protection \ forests \ plant diseases \ fungal diseases \ rust diseases \ stem