1987 July: Kobyboyn Area (Vic). Pesticides detected: Paraquat, Diquat

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Yea District

“…in the Yea district, drift from an illegal aerial application in 1988 of a product containing the pesticides paraquat and diquat damaged vegetation over an area of 100 square kilometres.”
Source: ‘Spray drift controversy: chemical not registered for aerial use.’ Goulburn and Marray Valley Country News, 19 July 1988. As cited in ‘Chemical Crisis, One Woman’s Story. Humanity’s Future?’ Diana Crumpler, 1994. Scribe Publication Pty Ltd, Newham Victoria, Australia. ISBN 0 908011 25 3.

The Event

5. The drift occurred following the aerial spraying of a hilltop with Sprayseed and sowing down with pasture on the morning and early afternoon of 2 July 1987.

6. It has been recalled that 2 July was a frosty night followed by a sunny morning until it clouded over during the afternoon. It has been claimed that a temperature inversion was operating at the time aerial spraying was taking place…

9. The conditions of the day cannot be accurately reconstructed now as there is no synoptic weather station near the spray site. Hilly areas are associated with complex air and wind movements. It is possible to have wind movements at a hilltop with still air in the valley as well as having air currents moving across a valley floor up a ridge, across a plateau and up a further ridge distributing spray all the way. This in fact happened.

10. As a result of the spray application on 2 July, Sprayseed drifted across an area in excess of 25,000 acres and up to 17 km from the application site.

11. Spray drift produced an observable effect on pasture grass and native and non-indigenous plants. Effect was most severe on those eucalypts closest to the spray site and over the whole area plants with broad leaves were most severely affected…

12. The effect on trees was first noticed *** at Kobyboyn around 14 July when affected plants were delivered to the Seymour office for diagnosis of the problem…

27. …In discussion with the people at Kobyboyn/Highlands Caveat, the issue of aerial spraying for the establishment of pine plantations in the Central Highlands was raised on many occasions. The encroachment of pine plantations in an area requiring extensive use of agricultural chemicals to ensure establishment of the plantations is clearly of concern to local residents. In the Broadford Shire, plantation owners have obtained Planning Appeals Board judgements granting permits that strictly limit the ways in which agricultural chemicals may be used; residents on the other hand do not believe that local municipalities have the appropriately trained personnel to ensure the permit conditions are abided with…