How to Manage Pests

Pests in Gardens and Landscapes

Graft incompatibility

Certain scion and rootstock combinations show an incompatibility reaction, which may appear shortly after grafting or may take 10 to 20 years to develop. An example of delayed incompatibility is bud union crease. A crease or fold forms at the bud union and, with increasing overgrowth, results in a slow girdling of the tree.


When planting or replanting, avoid susceptible combinations. For example, 'Frost' nucellar navel on trifoliate orange, lemon on 'Cleopatra' mandarin, 'Eureka' lemon or 'Satsuma' mandarin on 'Troyer', and certain scion lines on sour orange develop bud union overgrowths. For more information, contact your local extension office.

Crease forming at bud union
Crease forming at bud union

Statewide IPM Program, Agriculture and Natural Resources, University of California
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