Unhealthy plants are more prone to pests. Plants under stress give off infrared light which attracts bugs (who are the Sanitation Engineers of the natural world). To help determine the root cause of the problem consider the following:
- Check for water stress or water logging
- Check plant climatic requirements and time of year factors
- Check if fertilisers high in nitrogen have been applied. This will attract more pests who love eating plants high levels of nitrate nitrogen.
- Check pH and soil fertility
The following short term remedies can be applied:
- Strengthen plant resistance to pests – seaweed solution, potassium, silica
- Set traps – fruit fly traps
- Net trees or bag fruit
- Place pest deterrent – rubber snakes, CD, fake birds and cats, bird scarers, moth balls
- Apply gentle insecticides - soap spray, milk spray, wettable sulphur, herbal teas, and molasses
- Apply higher strength insecticides – neem, spinosad, derris dust
The following longer term remedies should be actively pursued:
- Increase the amount of organic matter in your soil. This will improve soil life, water holding capabilities, and more. The end result will be plants with greater pest resistance.
- Reminerialise your soil with rock dusts
- Adjust the pH of your soil to the level required by the plant
- Provide support plants which give habitat to all the beneficial predatory insects, frogs, and birds
Reference the BOGI Queensland Planting Guide for detailed information about ways to manage disease.