Vein Yellows (Red Mottle and Sooty Ringspot of Quince)

Pear nursery trees show small pale yellow vein-associated spots or irregular red mottle flecks on leaves, with stunted growth. Vein yellows virus (apple stem pitting virus) causes this latent infection. Use virus-tested scions and rootstocks. Heat treatment at 37°C and meristem culture can eliminate the virus. Trees tested virus-free show better vigor and earlier production.

Leaf spot and blotch diseases are primarily cosmetic on established plants, though repeated years of heavy infection can weaken them. Rake up and remove fallen leaves to reduce the spore load going into the next season. Avoid overhead watering that splashes spores from the ground onto lower leaves. If the problem is severe, protective fungicide sprays during spring leaf emergence can help, but sanitation does more than chemistry for most leaf spots.