A. Razik, A. Grinstein, J. Katan
Rhizoctonia was the major fungus isolated (77.5%) from strawberry plants showing growth retardation in commercial fields in Israel. In certain cases, it was isolated also from propagation material. Inoculations showed that isolates of Rhizoctonia exhibit various degrees of pathogenicity to strawberry plants as well as to other plants, e.g. beans, pepper, onion, cucumber, cotton, and radish. Pathogenicity of Rhizoctonia to strawberry was evident under both greenhouse and field conditions. Various symptoms were observed on inoculated strawberry plants: grey lesions on the runners and on the base of the petioles, distorted growth, bud rot, leaf desiccation and plant stunting. Under field conditions leaf distortion was visible as early as one month after inoculation. In the following weeks the symptoms described above, severe growth retardation and a reduction in the number of runners were observed in the inoculated plants. Virulence of isolates varied from very high to none. The virulence of Rhizoctonia isolates obtained from inoculated strawberry plants was lower than that of the parent isolates.

Plants inoculated with Rhizoctonia prior to planting in the field showed that Rhizoctonia can grow along the runners for at least 40 cm from the point of Inoculation. In a field trial, the performance of locally grown strawberry plants was compared with that of plants from meristem culture. The local plants showed poorer growth. Inoculation with certain Rhizoctonia isolates decreased plant growth and yield, while other isolates increased them.

It is concluded that Rhizoctonia is a serious pathogen of strawberry in Israel. Its control can be achieved through the use of healthy propagation material and soil disinfestation.

Razik, A., Grinstein, A. and Katan, J. (1989). RHIZOCTONIA DISEASE IN PROPAGATION MATERIAL AND FIELD GROWN STRAWBERRY. Acta Hortic. 265, 579-585
DOI: 10.17660/ActaHortic.1989.265.86

Acta Horticulturae