Pest and disease control
Pests and diseases of pastures can severely impact their productivity and the profitability of an enterprise.
The types of pests and diseases that affect pastures vary depending on the type of pasture, the region and the season.
Pasture pests include vertebrates, invertebrates, weeds and diseases. In this context, 'pests' describes invertebrates including redlegged earth mite, blue oat mite, heliothis caterpillars, black headed cockchafers, diamondback moth, aphids and lucerne flea.
Not all insects that live in pastures are problematic and there are a range of invertebrates that benefit pasture growth by preying on pests. These are known as 'beneficial insects' and include carabid beetles, predatory mites, native earwigs, brown lacewings, ladybird beetles and parasitic wasps.
While insecticides can be used to control pest species, they will also usually affect beneficial insects. An integrated approach to pest control which minimises insecticide use is often the most effective and sustainable approach.
Integrated pest management
Integrated pest management (IPM) involves using a combination of biological, cultural and chemical control methods to control pests. As beneficial insects are a key component of IPM, the use of insecticides is minimised, but not excluded altogether.
The first step in IPM is to identify and understand the lifecycle of the pests and beneficial insects present. A plan can then be put in place to manage the populations of both beneficial and pest insects. Careful and ongoing monitoring is then required to ensure that a favourable population is maintained and to allow corrective actions, such as slashing, pasture rotation or spraying, to be undertaken when pest numbers impact pasture production.
Disease and deficiencies pose a similar risk as pests and should be monitored when checking pastures for pests. Diseases can generally be classified as leaf eg rusts, or root diseases eg wilt or root rot.
Management for disease control should be proactive and reactive.
Proactive control begins prior to pasture establishment and takes into consideration paddock and disease history as well as pasture species selection for disease resistance. Reactive disease control involves managing outbreaks and may include strategic grazing and chemical application. In extreme cases, cultivation and cropping may be required to break a disease cycle.
Where chemicals are used to control pests and diseases, producers must be careful to abide by all Export Slaughter Intervals (ESI) and Withholding Periods (WHP) associated with the particular chemical.