BROWN LEAF SPOT
The brown leaf spot disease fungus Cercospora fusca (Heald and Walf) Rand affects only mature leaves and usually does not appear until the latter part of May or mid-June. Primary lesions develop on the lower leaf surfaces as small dots, which gradually enlarge and become reddish brown with a grayish cast. The shape of the lesions may be circular or irregular, especially where two or more lesions develop adjacent to one another, [Figure 2]. 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 resistant to brown spot disease.
Control.—See spray schedule, [page 4].