Burr Knots, What Are the Root-Like Growths on Apple Trees Trunks and Branches?

Burr knots (burrs or burls) are masses of small root initials, plant cells that are dividing and transforming into root tips, which appears on the above-ground portion of a rootstock, or on the trunk and limbs of apple trees. This is an inherited disorder where root-producing structures develop on aerial parts of certain apple trees.Continue reading “Burr Knots, What Are the Root-Like Growths on Apple Trees Trunks and Branches?”

Apple Tree Diseases – Crown Gall

Crown gall is a bacterial disease caused by Agrobacterium tumefaciens (syn. Rhizobium radiobacter), which produces tumour-like swellings on the bark of trees and plants. It can infect a wide range of dicotyledonous (broad-leaved) plants, particularly members of the Rosaceae (rose) family such as roses, raspberries, almonds, cherries, peaches, pears and apples. These disease-causing bacteria liveContinue reading “Apple Tree Diseases – Crown Gall”