An investigation of the foot-rot disease of wheat in New Zealand: with an intensive plant mortality and yield investigation in five fields affected with the disease

Two photographs (plates) are missing from copy. Plate III (p. 25), Plate VI (p. 53).

The wheat crop is affected by a number of diseases, some of which can be controlled by relatively simple practices on the part of the grower. There are other wheat diseases which do not admit of simple straightforward methods of control. Rust (Puccinia spp.) and the Foot-rot diseases have not received attention from New Zealand workers. Rust is recognised as an important disease, yet, because it is not a simple problem, it has been left alone. The Foot-rots are in the same category. They are not so conspicuous as rust, unless present in a severe form, and are generally overlooked. This, however, should not preclude an investigation of the disease. Of recent years, a number of workers in Europe, America and Australia have turned their attention to the Foot-rot diseases with the result that much information is available about the causal organisms. The virulence of the parasite, however, is influenced by complex factors acting on the host plant and on the organism so that specific control measures cannot be given. A number of severe outbreaks have occurred in Canterbury during the past few years and the present thesis is an account of an investigation which was undertaken during the wheat growing season of 1934-35 and part of the 1935-35 season. The objects of this investigation were: 1. To isolate and study the organism responsible for Foot-rot disease of wheat in New Zealand. 2. To study the symptoms of the disease. 3. To make a survey of the incidence of the disease under field conditions in wheat growing areas. 4. To investigate the means of control and prevention of the disease. 5. To estimate the loss in yield caused by the disease by intensive plant mortality studies and yield investigations on five fields known to be affected with Foot-rot.