Alternative control methods
John M Whipps, Warwick HRI, University of Warwick, Wellesbourne
Disease control has traditionally relied heavily on the use of chemicals and disease resistant varieties of plants. However, with increasing resistance of pathogens to chemicals, pressure to decrease chemical use in the environment, and reduced availability of active ingredients for disease control, the need for alternative means of disease control has now become even more important. This is especially so for soil-borne pathogens with the loss of the soil sterilant, methyl bromide. Traditional cultural and environmental procedures are still of value and are being adapted to the current situation. These commonly include quarantine, basic hygiene measures, use of crop rotations, soil steaming, solarization, and organic amendments.
Other more specialised techniques such as micropropagation for virus-free stock, thermotherapy for controlling seed-borne pathogens and vector control are also options. In the glasshouse, where environmental control is possible, other techniques such as humidity, temperature and fertigation control can be utilised as well. In addition, microbial inoculants (biological disease control agents) are gradually entering the market with at least 3 viral products, over 30 bacterial products and 50 fungal products available worldwide, including some recently available in the UK. The potential also exists to integrate some of these alternative disease control methods to enhance disease control further. Some specific examples based on the use of Coniothyrium minitans, Pythium oligandrum and Trichoderma viride will be discussed.