Procedures for the establishment and operation of approved seed plots: fourth edition 2013

Abstract

Hot-water treatment of sugarcane cuttings (stalks or stalk pieces) to control the spread of diseases and pests was pioneered in Australia. Hot-water treatment can reduce the risk of cuttings being infected with ratoon stunting disease, leaf scald, chlorotic streak, sugarcane smut and downy mildew and can free cuttings of insect pests. It does not usually control virus diseases such as sugarcane mosaic and Fiji leaf gall. Hot-water treatment is only a part of an integrated pest management program and must be used in combination with disease inspection, crop management and hygiene to reduce the risks of reinfection (see attached ‘Procedures for the establishment and operation of approved-seed plots’).

Protocols for hot-water treatment vary depending on the disease or pest that is the target. The temperature/time combinations most commonly used are close to the thermal death point of sugarcane. It is, therefore, critical that the temperature is not exceeded or germination will be severely affected. However, to obtain effective control of ratoon stunting disease and leaf scald disease, the temperature must not drop below the target temperature or the disease will not be controlled effectively. This means that temperature control must be maintained within narrow tolerances. Circulation of the water is also critical to ensure that all parts of the tank are maintained at the correct temperature and that there are no cold or hot spots. Checking of the temperature during each run of the facility is essential to ensure good disease control. A regular maintenance program is also essential to ensure the tank is operating correctly.