Pear Trees With Yellow Leaves

The leaves of a healthy pear tree in the growing season are glossy and dark green. Yellow leaves on a pear tree typically indicate that either winter is approaching and the tree is preparing for cold weather, or the tree has some disorder that is affecting leaf color. These disorders can include diseases or low nutrient levels that cause chlorosis, a yellowing of the leaves. For these disorders, careful treatment can help to return the leaves to a healthy green condition.

Pears are deciduous, losing their leaves as a defense mechanism to survive the cold of winter. When temperatures drop below a certain level, the pear tree inhibits the flow of nutrients and water into the leaves. As the leaves begin to die, the chlorophyll within them breaks down, revealing the background color of the leaf, which for pears is yellow. Eventually the leaves will turn brown and fall.

Certain illnesses can also result in pear tree leaves turning yellow. According to the University of California Statewide Integrated Pest Management Program, one example of a disease that produces yellow leaves is pear scab. With this disease, the leaves develop brown spots, then turn yellow, or chloritic. In severely affected plants, all of the leaves may turn yellow and eventually fall. Apple rust is another disease that can cause leaf yellowing in severe cases.

Chlorosis can also occur when trees do not receive sufficient nutrients from the soil. For pears, iron chlorosis is a particular problem. In many alkaline soils, the iron is not available to the plant. Chelated iron added to the soil can help reduce chlorosis caused by iron deficiency. Insufficient levels of other minerals such as zinc, sulfur, magnesium, copper and manganese can also cause pear tree leaves to turn yellow. Proper soil testing and supplementation with the appropriate nutrients can help the tree regain its health and restore green to the leaves.