Apple union necrosis and decline is caused by tomato ringspot virus, which also causes disease in other fruit trees, small fruits, and many herbaceous plants. Symptoms appear as infected trees reach bearing age. Bud break is often delayed in the spring, and leaves are small and sparse with a dull, pale green color. Terminal shoot growth is reduced, with shortened internodes. Infected trees flower heavily and set large numbers of small, highly colored fruit. Leaf discoloration and leaf drop occur …