Encouraging beneficials
Beneficial insects do not appear simply because pests are present. They need food, shelter, suitable conditions and enough stability to build populations and remain in the crop.
Natural pest control works best when beneficial insects can survive before, during and after a pest outbreak. A crop that provides pollen, nectar, alternative prey, shelter and undisturbed refuges is much more likely to support resident predators and parasitoids.
The aim is not necessarily to remove every pest. In many situations, small background pest populations help maintain beneficial populations and allow them to respond more quickly when pest pressure increases.
These principles can be applied in gardens, nurseries, protected crops, field margins and commercial horticulture. They also work alongside introduced biological controls rather than replacing them.
A short flush of flowers helps, but continuous flowering is much more valuable. Different plants flowering from spring into autumn provide a more reliable food supply for adult beneficial insects.
Small open flowers are particularly useful because nectar and pollen are accessible to insects with short mouthparts.
Beneficial populations are easier to maintain when some habitat remains undisturbed. Ground cover, mulch, hedge margins and permanent planting can provide overwintering and recovery sites.
Removing everything at once creates a biological reset. Pests often recover faster than predators.
Broad-spectrum insecticides can remove beneficial insects as well as pests. Even when a treatment is justified, consider where it is needed, what life stages are present and whether untreated refuges can be retained.
Biological control becomes easier when beneficial populations do not have to repeatedly rebuild from zero.
Regular crop inspection helps distinguish a rising pest problem from a population already being suppressed by predators or parasitoids.
Look for evidence such as parasitised aphids, predator larvae, predatory mites, eggs and feeding damage before deciding that another intervention is required.
Encouraging resident beneficials and releasing commercially produced biological controls are complementary approaches.
Habitat and food can improve the persistence of naturally occurring predators and may also help introduced beneficials establish more successfully. In higher-pressure commercial situations, releases may still be needed to build predator numbers quickly enough.