Insect management is an essential component of crop production, as insect damage can lead to significant yield loss or quality penalties.
Key points
- seek out the latest information on insect control, spray thresholds, and insecticide resistance management strategies
- keep fields and surrounding areas free of alternative hosts
- time crop developemnt to avoid periods of high insect activity
- aim to break insect breeding cycles (e.g. pupae busting, removing alternate hosts)
- regularly check crops for both pests and their natural enemies
- plan your monitoring around the crop stages most susceptible to insect damage
- spray if economically damaging insect populations are detected that natural enemies present are not likely to control
- ensure that spraying equipment is calibrated and in good working order
- consider weather forecasts in your seasonal planning and management decisions.
Monitoring your crops
Regular scouting allows timely control of insects but can take significant time. It is important to accurately know the type, stage and number of insects and beneficials present in your crop in order to make the correct control decision. Include insect monitoring in your budget when planning your cropping program.
Learn more about monitoring for pests and beneficials.
It may be worthwhile to pay a consultant or adviser who will perform crop monitoring at regular intervals and keep records of insect numbers. Consultants have both identification experience and ready access to chemical information and the choices available.
Good record keeping of both monitoring outcomes and management actions is essential. A record of crop inspections will indicate whether pest numbers are increasing, decreasing or remaining stable, and help to make spray decisions. Keeping spray records are a legal requirement of using pesticides – exact recordkeeping requirements will vary by product and state.
Considering natural enemies
When monitoring for insect pests, also keep an eye out for signs of predators, parasitoids or pathogens that may be contributing to in-field pest management.
Some entomopathogens are available in commercial formulations, and there are also a range of predators and parasitoids that can be purchased for inundative or augmentative release. Read more about biological control.
Making spray decisions
When deciding whether to spray, consider:
- numbers of eggs, larvae or nymphs, and adult pests
- development stage of larvae/nymphs
- spread of pest within the crop
- where the pest is on the plant
- presence of secondary insect pests
- insecticide resistance levels in your area.
- natural enemy activity
- weather conditions and risk of spray drift
- crop development stage (potential for yield loss and likelihood of compensatory growth)
- crop value
Consider the relative return on investment of a spray application. Spraying is usually only recommended when an economic threshold is exceeded (the potential crop value saved from damage is more than the cost of product plus application). Thresholds are expressed in numbers of insects per area or plant part.
Learn more about selecting chemicals and insecticide resistance.