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Results/key findings
The study demonstrated that IPM strategies were effective for Asian leafy vegetable crops. Scouting
for pests was critical to obtain an early indication of pest activity, particularly as many leafy
vegetables have a short crop cycle. In the Sydney Basin, IPM strategies achieved equivalent or better
management of two-spotted mites and diamondback moth compared to the use synthetic pesticides.
Two foliar diseases were important in Asian leafy brassicas. In the Sydney Basin, white leaf spot was
the dominant fungal disease while downy mildew was important in all production areas, particularly in
Asian baby leaf production and Chinese broccoli. Given the short crop cycle, forecasting for downy
mildew will be important to enable control when conditions are suitable.
Root diseases were important on farms with a long history of production in the Sydney Basin. Club
root was the most important disease of leafy brassicas and there are currently few management options
other than liming. One cultivar of Chinese cabbage showed tolerance to this disease. Thus far, it is not
evident in hydroponically grown crops and growers were encouraged to move to this production
technology for leafy brassicas as a means of avoiding club root. English spinach crops were severely
affected by a complex of fungal and water mould pathogens in soil production in the Sydney Basin.
The study demonstrated that certain chemical seed dressings have potential to reduce losses from these
diseases.
Turnip mosaic virus was sporadic but caused major losses in some leafy brassica crops. This was linked
to aphid activity and weed reservoirs on farms. Most significantly, much of the surveyed production areas
were in severe drought during the project period, excepting for the final summer and autumn. Aphid
activity and incidence of this virus were much greater during this latter period. The project team found
similar trends with the Asian melon crops and Watermelon mosaic virus infections.
The key pests identified in baby leaf crops were different to expectations. Aphids were not a major
issue, while the cabbage cluster caterpillar proved to be a significant pest.
In Victoria and New South Wales, pest pressure was found to change with seasonal conditions. In
some cases, pests that were insignificant in the early phase of the project became important in the
latter stages. For example, striped flea beetles were more important in the final year on brassica crops.
Rutherglen bugs, which were important on some host plants, reached plague proportions at various
stages. Possible reasons for this fluctuation are discussed but, like thrips, there are currently no soft
chemical or alternative management strategies. However, garland chrysanthemums were shown to be
potentially useful as a trap crop for Rutherglen bugs and thrips.
In NSW, the study team collaborated with other Government initiatives to improve grower education
and IPM skills. One hundred and fifteen growers were trained to Certificate III in Agriculture. This
included growers from Chinese, Vietnamese, Cambodian and Arabic backgrounds. In Victoria, LOTE
growers successfully completed the following training: farm chemical users training (17 growers);
food safety training (16 growers); and post-harvest training (14 growers). Several IPM workshops and
farm walks were conducted across four states.
The study was successful in changing grower practices. Improved farm and crop hygiene practices
were evident, particularly in regards to weed control and clean up of crop residues. Growers became
more aware of the components of IPM, including the range of pests, understanding that beneficial
insects exist and better and targeted use of selective chemicals. Significant change in chemical use
practices included the use of personal protection equipment and targeted spraying based upon pest
monitoring instead of application based on a calendar schedule. It will be important to ensure these
changes are sustained through regular community engagement and education.
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