Crown Gall on Raspberry
A couple of weeks ago I got a call from a grower and PCA concerning planting stock that had unusually large growths on the roots (pictured below) which are really typical of crown gall.
Crown gall is caused by a bacterium which enters the plant through wounds. Once inside, it causes affected plant cells to multiply and enlarge rapidly without real direction, ending up with these large galls which can get up to an inch in diameter. These enlarged areas can and do interfere with the movement of water and nutrients through the plant, so that a plant which is severely affected will not grow well and bear seedy fruit.
It goes without saying that avoiding injury to the roots and crowns is advisable, and given that fumigation is not seen as an effective measure, one should not introduce crown gall into the field in the first place. My call to the grower and PCA, which they had already made, was to not put these severely affected crowns and roots into the crown and dispose of them elsewhere.
Photo 1: Pronounced growth on rootsl typical of crown gall.
Photo 2: Another plant with roots affected with crown gall.