Let’s start with what is noticeable on the apple tree. The picture of the apple tree is a bit blurry, but it does appear to have powdery mildew. Powdery mildew is a fungus that causes a white felty-like covering to develop on the leaves of many fruit trees. It will overwinter in the terminal buds in apple trees. To help control powdery mildew, prune your apple tree to increase air circulation around the tree. Unless the infection is severe, cutting out any infected shoots as soon as they appear can help. Neem oil is labelled as a fungicide but will not cure powdery mildew and it is not listed for use on powdery mildew in Oregon. It may only limit the spread of the disease to healthy tissue. See Apple (Malus spp.) - Powdery Mildew for more information.

Pear trees can develop powdery mildew. The same fungus, Podosphaera leucotricha, causes powdery mildew on both trees. It is recommended that pear trees be planted upwind from apple trees and as far as possible from them and follow the controls mentioned above. Pear (Pyrus spp.) - Powdery Mildew is the reference for pears.

Codling moth can affect the fruit on both the pear and apple trees. It is a serious pest of which the larvae tunnel into the fruit and feed on it. It leaves frass, or excrement, that will rot the fruit. Neem oil, a pesticide, can be used to help control codling moth but needs to be used on a schedule after petal fall in the spring. The following articles help to explain when to use neem oil for best results, Apple - Codling Moth and Pear - Codling Moth.

Open wounds on any tree can be entryway for disease and insects. If they do not close naturally decay will begin and can cause the tree to be a hazard. If you have any wish to try and save the tree, you should contact an arborist to determine the best way to care for the tree.

The yellowing and browning on the edges the leaves of the entire pear tree can be caused by several factors. One cause is improper watering practices. When fruit trees are young, they need to be irrigated as much as 3 to 5 gallons of water a week. Water infrequently, but make sure the necessary moisture reaches deep in the soil to encourages a network of deep roots. In addition, there is vegetation around the tree and it can compete with the tree for water. It would be best to remove it and cover the area with mulch. Mulch can help keep the vegetation down and keep the soil moist and not dry out as quickly.

Neem oil, particularly when used on a new transplant or stressed tree, can damage plants by burning their foliage. Neem oil works best when the plant is completely covered, but in the future, it might be best to test it on a small area to see if the symptoms reoccur.

Nutritional deficiencies can cause some of the damage that is seen on the leaves. When lime is added to soil, it is used to adjust the soil’s pH and make it less acidic. Fruit trees like a slightly acidic soil, between 5.5 and 6.5. If the soil is too alkaline, it may not allow the tree to uptake all the nutrients it needs. It would be wise to test your soil’s pH before adding more lime or any other additive to your soil. The Lane County Master Gardeners are doing pH testing this Saturday, November 5^th, from 1 to 4 pm. If you are interested, Soil pH Testing has more information on cost and how to collect a sample.

How much and how often you fertilize your pear trees was not mentioned. Make sure you are not overfertilizing, this can also cause the leaf damage at the margins. After the first year only 1/8 of a pound of active nitrogen per year of age is recommended in a balanced fertilizer.

Providing your pear trees with a healthy growing environment that includes proper water, sun, and soil conditions will increase their tolerance to resist insects and disease. For more general information on how to care for pear and apple trees see Growing Tree Fruit and Nuts in the Home Orchard.