• Change text size
• Skip to content

• About us
• Contact us

Environment home

• SoE
• About SoE reporting
• SoE 2011
• SoE 2006
  • SoE 2006 report
  • SoE2006 at a glance
  • Theme commentaries
  • Integrative commentaties
  • Current or emerging issues
  • Technical reports
  • Data Reporting System
• SoE 2001
  • Report
  • Key findings
  • Fact sheets
  • Theme reports
  • Technical papers
• SoE 1996
  • SoE 1996 report
  • Key findings brochure
  • Technical papers
• Publications

SoE themes

• Atmosphere
• Biodiversity
• Coasts & oceans
• Human settlements
• Inland waters
• Land
• Natural & cultural heritage
• Australian Antarctic Territory

Soil and land pollution (continued)

Condition (continued)

Progress in Integrated Pest Management and risk reduction in agricultural industries: case studies

Risk assessment

Today environmental impacts can only be estimated by consideration of the types of chemicals habitually used in rural industry relating to land use. CSIRO is trialling a Pesticide Impact Ranking Index (PIRI) (Kookana et al. unpubl.; see PIRI: Pesticides Impact Ranking Index) that has the potential to provide relative assessment of the potential impact of different chemicals used in rural industries.

Integrated Pest Management: cotton [L Indicator 6.11]

The collapse of the cotton industry in the Ord Irrigation Area in the 1970s, following the build-up of resistance to pesticides, was an object lesson to the cotton industry. Cotton communities remain concerned with insecticide risks and careful monitoring and control programs are in place across Australia. The industry and its research collaborators have worked to develop Integrated Resistance Management (IRM) and Integrated Pest Management (IPM) systems that are now widely practiced. Almost all the irrigated cotton in Australia is intensively 'bug checked' every 3-4 days. Insecticides are applied only after threshold numbers are reached, with more selective products used in preference to older broader-spectrum groups wherever possible. In addition, different insecticide groups are rotated in an attempt to manage insect resistance. The Australian Cotton Cooperative Research Centre has recently developed practical IPM guidelines. These include breeding varieties that are least attractive to insects, management of fertilisers, timing of irrigation and defoliation. While environmental audits undertaken for the cotton industry show good levels of compliance with such guidelines, episodes of pesticide contamination in beef, waterways or the atmosphere still occur, and present a significant risk to communities, trade and the environment.

Of the 400 000 to 500 000 hectares of cotton grown in Australia each season about 30% is now genetically modified 'Bt' (Ingard ) cotton. In the past three years there has been an average 42% reduction (ranging from 30% to 60%) in insecticidal spray used against cotton bollworm or 'heliothis' (Helicoverpa armigera) on Ingard cotton crops. This has resulted in 1.75 million litres less pesticide being used on such crops. The pesticides in question were mainly endosulfan, but carbamates, organophosphates and pyrethroids are also used (ACIL Consulting 2000). Other components of IPM include the fostering of conditions that encourage beneficial insects, such as foliar food sprays, and using alternatives to 'hard' chemicals such as foliar-Bt sprays, and trap crops grown alongside cotton.

The remaining 70% of conventional cotton crop still requires a total of 10 to 18 spray applications of herbicides, insecticides and fungicides each year. New transgenic crops may need from three to ten sprays of similar chemicals. (Holloway pers. comm., ACCRC 2000). However, research has indicated that the use of Bt cotton has caused changes in soil microbial populations (Gupta et al. 1998). This would suggest a more precautionary approach may be required in the use of these genetically modified crops.

Integrated Pest Management: horticultural crops [L Indicator 6.11]

Australia, and other western countries, now sell over 75% of fresh fruit and vegetables through supermarket retail chains. Sales depend on the product being attractive, unblemished and of a sufficiently regular size to attract consumers. In addition, consumers require that there is no health risk from pesticides.

Horticultural crops are often grown in small blocks, mostly under irrigation and close to settlements. The crops are very vulnerable to many pests and diseases. To control the full range of pests, diseases and weeds that would make the product unsaleable, most crops require around 20 to 30 sprays of all kinds per growing season. The adoption of IPM will normally reduces this by about 20%, but also reduces the off-site impacts by up to 50% (Juffs et al. 1999).

A recent study of tomato growers found that most processing-tomato growers, all of whom are located in Victoria, started to use IPM in 1995. By 1998, 89% of them had adopted the full range of IPM practices, principally because processing companies demanded certified product (Juffs et al. 1999). The same study found all fresh tomato growers in the Bowen region of Queensland had fully adopted IPM, and in the Bundaberg region, 95% of the tonnage was produced with restricted pesticide use, although only 77% of growers had adopted full IPM. Eighty percent of apple and pear growers have adopted some form of IPM in the past nine years. 20 to 30% of larger growers are in transition to a system of Integrated Fruit Management in which the whole farm or even the district is managed in the most sustainable manner currently possible (Agtrans Research 1999).

IPM in horticultural crops requires some or all of the following measures:

• change in farm practice,
• employment of a crop scout or training in scouting for all pests and diseases,
• use of sprays only when the pest level reaches a described threshold,
• rotation of chemicals to reduce build-up of resistance,
• use of more targeted chemicals, and
• production breaks or rotations for paddock hygiene.

Additional, more sophisticated levels of IPM include:

• using beneficial insects such as ladybirds, lacewings and sucking bugs that parasitise pests,
• using pheromone mating disruption systems to confuse male pests (very valuable in orchard crops),
• understanding the life-cycles and epidemiology of pests and diseases,
• growing companion crops, buffer strips, wind breaks and green manures, and
• adjusting spray technology to ultra low volumes, improved targeting and calibrations.

GM crops

During the past five years genetically modified (GM) crops have become a commercial reality in certain industries and regions of the world, but their introduction has become a matter of great public debate.

Australia has taken a cautiously positive approach to the development of GM crops, with joint government and industry funded research and development in grains, horticulture, cotton, pasture legumes, sugarcane, and tree crops. Biosafety and ethical standards were regulated through the Genetic Modification Advisory Committee (GMAC) until 1999, when the Commonwealth government developed the Interim Office of the Gene Technology Regulator. Subsequently initiatives to improve community understanding and information on a wide range of biotechnology issues have been undertaken. These have included a consensus conference to obtain community views in 1999, and the establishment of Biotechnology Australia, a consortium of government science, technology and industry groups that aims to improve information and education on genetic modification technologies. The Council of Australian Governments (COAG) agreed to guidelines and legislation on labelling, use, and segregation management of GM crops in October 2000. At the time of writing the main points in these guidelines are:

• States and territories, or geographically defined parts thereof, may identify areas that may declare themselves GM crop free or GM crop occupied if this is the consensus of the community.
• Crops being tested must go through the current scheduled procedure before field evaluation, but once being grown, any damage done to the test crop will be judged illegal and prosecuted. Field trial sites must be identified as such.
• Food will be labelled as to whether it contains a GM ingredient: if labelled GM free it must not knowingly have GM ingredients, but can contain up to 1% of inadvertent contamination.

The majority of broadacre GM crops being developed in Australia, and those that have been produced in other countries, and may be grown here, have been designed to withstand commonly-used herbicides. The intention is that the farmer can then use a herbicide to which the crop would normally be susceptible (such as a broadleaf herbicide used against Brassica species of weeds in a crop of canola, which is itself a Brassica). In the case of canola, naturally occurring herbicide resistant varieties have also been identified from conventional plant breeding selection procedures.

A few examples exist of crops that have been produced for improved quality (such as tomatoes with a higher proportion of solids), and market fashion (such as inserting 'blue' colour into non-blue flowers such as carnations and roses). There is intense research interest in such quality attributes as maintaining ripe fruit and vegetables without browning. Most of these transformations are possible with conventional breeding techniques but are less easy to protect by patent.

Implications

Irrigated cotton poses the highest environmental risk from pesticides in Australian agriculture, both because of the number of chemicals used and the frequency of use. Because of the very poor state of knowledge on total chemical usage, not only in agricultural industries, but across all sectors, the relative risks from the conventional and GM crop production systems are difficult to compare.

The issue of resistance to pesticides is a complex one. The early use of some pesticides was over-enthusiastic and profligate, and resistant populations have built up in many instances. As a result, Australia now possesses some of the most challenging examples of herbicide resistance known. Examples include the multiple-herbicide resistance displayed by weeds such as wild oats, capeweed and ryegrass (Lolium perenne). Such weed species frequently develop cross resistance to chemical groups to which the particular plant population has never had exposure, simply because it has had exposure to another chemical group. For example, exposure to sulfonyl ureas can lead to resistance to FOPS (the aryloxy phyonxyproprionate group) (Gill 1994).

While integrated pest, weed or disease management is the ideal solution to resistance, the examples given in this section demonstrate how challenging it is to implement such management across a whole district or industry. This is especially so when the pest, weed or disease is highly destructive, very widespread and where conventional plant breeding has not been able to confer resistance or competitive survival.

• Next
• Contents
• Previous