Foliage Diseases

Brown Leaf Spot (fungus Cercospora fusca)

Key words: Late season, defoliation, weak trees

The disease of pecan tree foliage known as leaf spot affects only mature leaves and usually does not appear until mid-June or July. Primary lesions develop on the lower leaf surfaces as small dots that gradually enlarge and become reddish-brown with a gray cast. The shape of the lesions may be circular or irregular, especially where two or more lesions develop adjacent to one another. In seasons favorable for brown leaf spot development, pecan trees may be completely defoliated within 3 to 4 months, if the disease is not controlled. Most pecan varieties which are maintained in a vigorous state of growth are not as susceptible to this disease. The fungus has been observed causing the most damage in the West Cross Timbers and on the 'Burkett' variety.

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