Pear Vein Yellows Virus

I. Introduction: This disease is caused by the apple stem pitting virus.

II. Symptoms: Symptoms are most pronounced under cool conditions, and consist of yellow vein banding, especially of the smaller secondary veins, red mottling and flecking along veins, and occasionally necrotic spots.

Pear Stony Pit

I. Introduction: The causal agent of pear stony pit has not yet been isolated, but it can be transmitted by grafting. Severely infected cultivars include 'Beurre Bosc', 'Doyenne du Comice' and 'Worden Seckel'.

II. Symptoms: Symptoms begin as early as three weeks after petal fall, when dark green spots form on the fruit. Areas surrounding these spots continue to grow while spots stop, resulting in misshapen fruit with pits (photo 2-48). Pits often become necrotic and the fruit beneath becomes sclerotized; heavily pitted fruit may become so gritty that it is difficult to cut with a knife. Pimpling and cracking of the bark, stunting of the trees, and chlorotic vein-banding or mottling have also been reported.

III. Management:  Select virus-free trees for planting.  Infected trees should be removed, but be aware that removing all infected Bosc trees in some orchards could reduce Bartlett pear yields because of lack of sufficient pollination.

Text prepared by E.V. Podleckis and R. Welliver

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