Hover flies can be easily confused with bees and wasps.

Revegetation by design: the Queensland bush working for you

Scientists are researching native vegetation as a means of developing improved pest management strategies for vegetable systems.

• 13 May 2008 | Updated 14 October 2011

• About the project
• How can native vegetation help vegetable farmers?
• Additional advantages of native plants

CSIRO and the Queensland Government Department of Primary Industries and Fisheries (DPI&F), Australia, are collaborating on a project designed to investigate native vegetation as part of Integrated Pest Management (IPM) for the vegetable industry.

About the project

This project builds on research results for the field vegetable cropping system.

Results from three major project activities will soon be completed and include:

• a desktop review asking when is native vegetation a risk for pests and diseases to vegetable crops in Australia?
• experiments on pest and natural enemy movement from native remnants to vegetable crops
• community engagement to ensure good information exchange, shared learning, and practical outcomes.

How can native vegetation help vegetable farmers?

Native vegetation can help with vegetable pest management in two ways:

• maintaining existing remnants
• planting native vegetation on-farm.

First, research from Queensland has found that natural enemies of agricultural pests, particularly hover flies, and parasitoids, visit the edge habitat between agricultural crops and native remnants and sometimes move far into the remnants.

This is a first step in showing that natural enemies use habitats beyond the vegetable fields.

The next step is to show how native remnants adjacent to vegetable crops lead to better pest suppression.

For example, if natural enemies are close by they may be able to respond to pests in the crop more quickly.

Second, growers can plant native vegetation that does not harbour pests and replace weedy habitat that does.

Research from protected cropping systems in the northern Adelaide Plains, South Australia and fields in Lockyer Valley, Queensland, has shown that:

• thrips, which are pests of vegetables and cause feeding damage and vector disease (tomato spotted wilt virus) are abundant on the most common weeds throughout the region, whereas they are rarely found on numerous species of native plants
• jassids, or leafhoppers, which cause cosmetic damage and vector diseases to vegetable crops, are frequently found in high numbers in exotic weedy grasses around vegetable farms
• predators and parasitoids of vegetable crops quickly colonised newly planted native plants, hence these new plantings are suitable habitat for natural enemies.

Additional advantages of native plants

1. long term weed management
2. decreased source of disease and virus sources around crop
3. enhanced biodiversity
4. profitability from the native plant seeds to the revegetation industry, bush tucker, or native floriculture.

However, not all species of native plants are well suited for planting around farms.

The vegetable leafhopper is a serious pest throughout many vegetable growing regions of Australia.

Natural enemies of vegetable crop pests are often found in plants which surround cropping environments.

In our current work we are profiling native plants to meet several criteria before recommending them, including identifying those plants that are:

1. not a host plant of vegetable pests or diseases
2. low growing, shrubs or ground cover allowing for movement of farm machinery, no shading of adjacent crops, good weed competitor and retention of top soil
3. provision of nectar and pollen for predators, parasitoids and pollinators.

Weedy areas on farm that may be revegetated including:

• riparian zones (creeks and rivers)
• ditches
• headlands
• fence rows.

Understanding the pests and natural enemies and their relationship with native vegetation (plants and remnants) will help us design our future cropping system for multiple benefits including:

• better pest and weed control
• enhanced biodiversity
• profitability.

Furthermore, this approach may create a market advantage by capturing consumer values linked with vegetable and the environment.

Read about our research on the Management of remnant vegetation.