I need to know how to treat pecan tree fungus, any ideas? I don't see why I have to add more info.
Scab is the most common and damaging pecan disease. It is caused by a fungus that affects rapidly growing leaves, shoots, and nuts. Symptoms on all plant parts are similar. Velvety olive-brown to black spots occur on the husks. Several spots may develop to form black blotches or may blacken the entire surface of the husks. Severely affected nuts of susceptible varieties may drop prematurely or they may stop growing, die and remain attached to the shoot. Leaf symptoms first appear on the underside as tiny olive-brown lesions on the veins. Later, leaf symptoms appear on the upper surface as small olive-brown to black spots. Severely infected leaves may be shed prematurely and weaken the tree, thus reducing the crop next year. The most practical method of scab control is to plant varieties having some degree of resistance to scab such as: Desirable, Cape Fear, Elliott, Chickasaw, Gloria Grande, and to a lesser extent, Stuart. Varieties severely affected by scab are Schley, Mahan, Success, Van Deman, and Mohawk. Use of "resistant" varieties does not necessarily assure complete absence of the disease as no variety is totally resistant. If possible, removing and destroying all leaves and husks may help reduce the amount of scab the following year.
A spray schedule is available for growers who have spray equipment adequate to cover the trees, or for growers who hire custom spray applicators. The following fungicides are registered on pecans: benomyl (Benlate 50WP), propiconazole (Orbit 3.6EC), fenbuconazole (Enable 2F), and thiophanate methyl (Topsin-M 70WSB). Spray applications should be made every 2-3 weeks beginning when leaves first emerge until shell hardening (early August). Spray at 2-week intervals when the tree is growing rapidly or during wet periods. Check fungicide labels for restrictions on grazing in sprayed orchards and the need to use tractors with enclosed cabs while spraying.
Jul 22, 2014 |