hard brown spots on all new leaves of pear trees

Asked April 15, 2017, 6:44 PM EDT

We have 5 pear trees, all of different varieties, that are less than 5 years old. The new leaves are just forming but all of them on all the trees have hard dark brown spots covering all the leaves. What is it and what can I do to help the trees? I sprayed with an anti-fungal and a copper spray over the winter.

Josephine County Oregon fruit trees

1 Response

The longer this spring stays wet and the warmer it gets, there are more chances that we'll see problems with pear scab in our fruit. You'll first see smoky, green spots on the leaves. A maze of velvety spots on the leaves will enlarge and turn hard crusty brown until these spores eventually infect the fruit. Black spots then appear on the fruit, causing it to crack and rot. Flowers and young shoots and leaves are particularly susceptible to the spores. The volume of rain doesn't matter; rather, it is the duration of the wetness that can rouse plant diseases such as apple and pear scab. Infection can occur after leaves stay wet for 10 to 25 hours.

To control the disease, take care to rake leaves after they fall and put them in a hot compost pile or yard waste disposal bin. Prune during the dormant season in late December to March to increase airflow and dry the leaves faster. You can also plant scab-resistant apple and pear trees. When flowers are blooming and buds emerge, it is time to spray fungicides. Wait, though, until the leaves have stayed wet for several hours.

You can also manage diseases such as scab by selectively snipping off fruit, including diseased fruit, in late spring and early summer. This thinning increases air circulation and has the added benefit of improving fruit size and quality.

Thin apple and pear trees in May, about a month after full bloom. On apple and pear trees, clusters of blossoms emerge from spurs, or pieces of wood that grow from the branches. Pears and apples produce several flowers per spur each spring. When fruit develops, it can weigh down the branch attached to the spur, he said. After tiny fruit appears in the late spring to early summer, use pruning shears to snip about four or five fruits off each spur, leaving one fruit per spur.

For more information about fruit tree care, view the publications below:

http://extension.oregonstate.edu/gardening/use-prevention-methods-fight-fruit-tree-diseases-2

http://extension.oregonstate.edu/polk/sites/default/files/MG_Handouts/managing_diseases_and_insects_in_your_home_orchard_0.pdf

Hope this helps!