Since repeated use of the same area greatly increases the amount of disease, rotation is essential. When available, it is also helpful to use resistant varieties. Chemical controls are not effective for these fungi. Stem rot, Rhizoctonia solani . The above-ground symptoms of this are nonspecific and include a general yellowing, wilting, and collapse of the foliage and the entire plant.
Dark lesions are sometimes visible on the stem at or near ground level.
Control can be difficult once plants are infected so prevention is important. It is helpful to avoid overwatering, especially in heavy soils, and to avoid watering directly into the crown area of the plant. Highly symptomatic plants can be rogued and removed since recovery is unlikely. Insect Problems See Carnation .