Field and landscape management to support beneficial arthropods for IPM on vegetable farms (VG16062)
What’s it all about?
This investment is designed to support Australian vegetable growers in harnessing the power of beneficial arthropods in integrated pest management (IPM) approaches. Specifically, it brings together a range of researchers and professionals in the field, who will capture information, develop and test strategies, and produce crop-specific and region-specific guidelines for field and landscape management to support beneficials.
Field surveys have been completed for insect pests and beneficials (predators and parasites of pests) in corn, lettuce, capsicum, bean, carrot and brassica vegetables across Australia. The project team’s major finding was that the type of land use adjacent to the crop strongly influences the number of pests and beneficials in the crop itself.
Habitat management strategies and potential candidate plants are now being tested in several field trials:
- Sweet alyssum, buckwheat and cornflower were identified as potential floral resources to attract and support beneficial insects in controlling a diverse group of insect pests in vegetable crops, such as brassica, lettuce, capsicum and sweet corn.
- Yellow rocket, Chinese cabbage and green collard were identified as potential trap crops for diamondback moth.
- Sorghum was found to be a potential banker plant to harbour the natural enemies of capsicum pests.
- Onion, tomato, barley and yellow sweet clover were identified as useful crops for intercropping with brassica for pest management.
- Sweet corn and coriander can be intercropped with different bean crops.
Only those plant species that can grow well in the Australian agroecosystem, are readily available, and are not known to have caused any significant ecological disservices in Australian farming systems are being considered for any recommendations.
Read an overview of the project in this article, Working with growers to secure a cleaner, greener future, published on page 38 of Vegetables Australia, July-August 2019.
The research team began with an extensive survey of insect pests and beneficials (predators and parasites of pests) in almost 500 crop fields of corn, lettuce, carrot and brassica crops across South Australia, Western Australia, Tasmania, Queensland and New South Wales.
The survey results were very encouraging and informative. Pest control in organic sites was found to be just as effective as those managed with insecticides, showing the benefits of higher numbers of beneficials in those fields.
The type of land use immediately adjacent to the crop was found to strongly influence numbers of pests and beneficials in the crop itself. Results suggest that local management—the layout of crops, roads, dams, water courses and pesticide use—may be a more important influence on pest numbers than landscape scale factors.
For example, beneficial insects and spiders were more common in the margins of crops, rather than in the centre, where fields were next to shelterbelts, rivers or plantings of sweetcorn. Pests also tended to be scarce in crop margins close to canola, carrot, pasture, roads and farm dams. Conversely, pests tended to be more abundant in crop edges adjacent to brassica crops.
Crops of a given vegetable species planted next to each other tended to have fewer beneficials and more pests, but separating crops by areas of other land uses, including crops of other species, boosted the numbers of arthropods. For example, sorghum strongly increased beneficial densities and reduced pests in nearby capsicum. Corn and capsicum crops also had similar effects in the overall survey.
The project team speculates that some of the factors at play include earlier maturing crops attracting beneficials, and features such as roads or dams acting as barriers to pest movement. Vegetation along creeks and rivers can contain perennial vegetation or flowering plants that seems to boost beneficials by serving as shelter or nectar sources.
A literature review of habitats likely to encourage beneficials supports these early results. Future trials are planned to investigate specific practices.
The team recommends that where possible, brassicas, sweetcorn, lettuce and carrots should be grown away from brassica vegetables and close to carrot, sweetcorn, canola, pasture, roads, dams or riparian vegetation.
- Further work is required to learn more about the impact of beneficial arthropods for integrated pest management, and that’s exactly what the team will be doing in the next phase of the project. If you’d like to be involved, please contact Geoff Gurr at firstname.lastname@example.org.
- Read an article from the project team on how beneficial insects can suppress pests in vegetables.
- Read about the project in the May 2018 edition of Vegetables Australia.
This project is a strategic levy investment in the Hort Innovation Vegetable Fund