Considerations when assessing management options
A range of factors can influence decisions about the most appropriate options for pest management:
- Accurate monitoring. Is the technique used effective at finding pests (and beneficials)? Is there a difference in spatial distribution (e.g. high counts along crop edge)? Do indicator traps suggest a potential infux of pests?
- Correct identification. Misidentification can lead to inappropriate pesticide use and a potential spray fail.
- Availability and relevance of economic thresholds. How reliable are available thresholds when applied to the current situation? Is quality a factor (contamination or % damage)?
- Population dynamics. Are populations likely to naturally increase or decline? Can beneficials maintain pests below threshold levels?
- Potential for damage. Knowledge of crop and pest growth stages, how they interact, and the potential for yield loss.
- Crop compensation. Will the crop have sufficient time/resources to compensate for damage?
- Secondary pest problems. Are there other potential pests that must be considered (e.g. aphids may not have reached a damage threshold, but virus is present in the crop; early or ‘hard’ spray kills beneficials resulting in outbreak of different pest)
- Crop health. Disease pressure, poor nutrition, moisture stress or waterlogging will impact on a plant’s ability to cope with invertebrate pest pressure.
- Other contributing factors (such as weather conditions, previous rotations etc)
Barriers to IPM adoption
- Lack of data. May be due to time constraints, low confidence in identification skills, or difficulty spotting small or highly mobile arthropods. Without accurate knowledge of pest and beneficial activity and distribution, and a good understanding of the interaction with the crop, it is difficult to estimate the likely pest impact.
- Fear of risk. Using thresholds rather than a prophylactic spray regime may be out of the comfort zone of some. However, using thresholds is more economically appropriate, decreases the risk of resistance, and reduces overall chemical usage thus minimising the impact on both beneficial populations and the wider environment.
- External factors. Unexpected events or stresses such as unseasonal weather conditions, unusually large influxes of migratory pest or extreme pest pressures can restrict the number of management options available.
