In protected horticulture strict hygiene can so completely eliminate inoculum of some obligate parasites that there is no need for the use of chemicals to control them. In agricultural practice elimination of indigenous pathogens is seldom a feasible option, and for some the rate of increase is so rapid as almost to obviate the benefits of inoculum reduction. In many situations, however, a reduction in the initial level of inoculum can greatly augment the use of other methods of delaying epidemic development and can thus form a vital component of a disease control strategy. The use of chemical fungicides is routine practice in agriculture and horticulture throughout the world as a measure to provide protection against yield and quality reducing plant diseases. The need for fungicides should however always be questioned, as they are only a part of the integrated management of crops and are almost the final step after consideration of agronomic good practice to reduce the occurrence and effects of pathogens.
New technologies bring new opportunities for disease control.
We therefore have several new possible approaches to plant disease control to really provide alternatives to the conventional fungicide one. Chemical fungicides are increasingly selected for yield and quality effects rather than purely disease control. The current status of these new technologies can be reviewed with their possible impact on future management strategies. A major issue with new technology such as transgenic crops is acceptance by the public and in the market place, this could be a real barrier to advances being made.