The best control is usually obtained with three to five sprays applied in the spring. Soil applications may be less effective than sprays because of the alkaline soils, which will reduce the availability of the zinc. However, soil applications may be preferable for home gardens where spraying is not practical. In addition, commercial growers may try soil applications on trees that have not responded to foliar applications. The tumor-like growths at the base of the tree were caused by the crown gall bacterium, Agrobacterium tumefaciens.
Some trees infected by crown gall grow poorly, have severe die-back, and eventually die.
Other trees may show no effect from infection and live for many years. For control of crown gall, refer to NMSU Cooperative Extension Service Guide H-645, Pecan Diseases and Their Control. The dark, dead areas on this root were caused by a lack of oxygen as a result of poorly drained, water-saturated soil. If not corrected, limbs will start to die from the top of the branches. The soil can turn black and have a putrid odor.