Research through the Graham Centre for Agricultural Innovation aims to develop ecological approaches to boost beneficial insects to check pest build up in vegetable crops.
The project is led by Charles Sturt University (CSU) Professor Geoff Gurr and is funded by Hort Innovation.
“Pressure is mounting to reduce reliance on insecticide spraying to control vegetable pests,” Professor Gurr said.
“Our research aims to help growers by developing methods that are simple to implement, compatible with mainstream farming operations and can help drive down costs.”
Surveys provide insight
The project team, including CSU Post Doctoral Research Fellows, Dr Syed Rizvi and Dr Ahsanul Haque has been busy surveying insect pests and beneficials (predators and parasites of pests) in corn, lettuce, carrot and brassica crops across South Australia, Western Australia, Tasmania, Queensland and New South Wales.
Professor Gurr said early results are providing useful pointers to what factors influence the abundance of beneficials and the pests they attack.
“First, among the sites that were under organic production, beneficials were much more numerous than in conventional crops where synthetic insecticides were used.
“This enhancement of beneficials kept pests in check as effectively as insecticide spraying in the conventional crops, it shows the potential of biological control.”
Fig. 1 Numbers of pests and beneficials in vegetable crops under ‘inorganic’ management, i.e. with use of synthetic insecticides and organic production. Pests are no more common in the organic crops than in inorganic crops, largely as a result of the significantly greater numbers of beneficial insects (predators and parasites). Here the average numbers are shown for a survey of 149 crop fields in Australia. Stars show where averages are statistically significantly different when comparing ‘inorganic’ and organic beneficial insect means. Numbers in brackets show the numbers of sites of each type of management.
Land use is important
Professor Gurr said organic farming is not for everyone and a key part of the research is examining what else might farmers try as a more integrated pest management approach.
“The second major finding from the field surveys is that the type of land use immediately adjacent to the crop strongly influences numbers of pests and beneficials in the crop itself; sometimes to the benefit of growers, sometimes to their detriment,” Professor Gurr said.
This is an important finding because other work, recently published in the American journal, Proceedings of the National Academy of Sciences, showed that simply having lots of natural vegetation in the wider landscape was no guarantee of lower pest numbers. Read more on CSU News here. (link to CSU News story)
“It seems that local management may be a more important influence on pest numbers than landscape scale vegetation patterns.
“This is actually good news for farmers because it implies that the things directly under their control, like pesticide use patterns, the layout of crops in relation to each other, and features like roads and dams, are what really matter. “
Further work is required to get to the bottom of these types of effects; and that’s exactly what the team will be doing in the next phase of the Hort Innovation project.
Graham Centre researchers working on the project include Professor Gurr, Dr Syed Rizvi, Dr Ahsanul Haque and Ms Annie Johnson and NSW Department of Primary Industries senior research scientist Dr Olivia Reynolds.