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Thursday, 18 October 1984
Page: 2028

Senator CRICHTON-BROWNE(10.23) —I for my part welcome the introduction of the Biological Control Bill 1984 as it establishes a very necessary mechanism whereby programs of biological control may be authorised for implementation after a process which allows proper opportunity for public discussion and comment. The specific occurrence which precipitated this legislation arose from the attempt to introduce a program of biological control aimed at echium plantagineum, better known as Paterson's curse--

Senator Macklin —Salvation Jane.

Senator CRICHTON-BROWNE —Or Salvation Jane, according to one's particular viewpoint. Paterson's curse is a native of the Mediterranean region and western Europe including, of course, Great Britain. It was from Britain that a certain Mrs Paterson is reputed to have brought the plant for her garden in Albury in New South Wales. Paterson's curse is now widely established in all states except , surprisingly, Tasmania, and is proclaimed a noxious weed in the whole of Victoria, and parts of South Australia, Western Australia and New South Wales.

The speed with which Paterson's curse spreads was demonstrated in a report on infestations of Paterson's curse in Western Australia, by G. A. Pearce and J. R. Peirce. This compared the infestation of Paterson's curse in 1960 with infestations in 1970. In Western Australia, as I said earlier, only part of the State is affected by the plant. In this area in 1960, 9,354 hectares were infested with Paterson's curse. By 1975, this had increased enormously to 109, 234 hectares. Infestations of Paterson's curse cause major problems for agriculturalists. The plant's competitive nature is such that it can eliminate more useful pasture species. Although Paterson's curse has some fodder value during winter and early spring, it becomes woody and inedible during the critical late summer and autumn season.

In Victoria, a committee was formed to examine whether biological agents for the control of Paterson's curse should be released. The Committee in its report, completed in 1978, estimated the potential loss in production to the livestock industry, likely to be caused by competition from Paterson's curse. In north eastern Victoria alone, the committee estimated the production loss to be $4.75m annually, the greatest loss being in the beef industry interestingly enough. This was described in that report as a conservative estimate.

Paterson's curse is also known to contain a number of alkaloids which, as other speakers have said, may cause liver damage in animals which may lead to eventual death. Sheep are less susceptible to this effect than horses and cattle, although there is apparently a cumulative effect after sheep have grazed on Paterson's curse for several seasons. Damage caused by Paterson's curse may also be accelerated when animals graze other plants containing alkaloids, such as heliotrope. The Commonwealth Scientific and Industrial Research Organisation, in a Press release issued in May 1984, stated that the effects of Paterson's curse on livestock are not definite, but went on to say:

Horses, cattle and sheep poisoned in the field have been diagnosed as poisoned by Paterson's curse after proper investigation . . . A controlled feeding experiment by the N.S.W. Department of Agriculture has shown that pigs may be poisoned in a few months by a fairly low proportion of Paterson's curse in the diet.

CSIRO therefore concluded:

Farmers making regular use of Paterson's curse for grazing animals should still take toxicity into account.

Some alkaloids are also toxic for humans, and low levels of alkaloids have been detected in honey produced from Paterson's curse plants. Mr J. E. Peterson, from the CSIRO Division of Animal Health, in his speech to the second Australia-USA Symposium on Poisonous Plants in Brisbane in May this year, made it clear that at present there was no indication that honey containing alkaloids from Paterson 's curse posed a significant risk for human consumers, although he did make the following point:

The risks associated with prolonged low level dosage in humans are unknown, particularly those that arise from the carcinogenic potential of the alkaloids, and are difficult to assess.

Of course it is the apiarists, as Senator Hill has said, who have strongly opposed any biological control of Paterson's curse, because of its abundant supply of nectar and pollen for honey bees. The resultant light coloured honey is exported and used to lighten and thus improve the marketability of darker honey. Ultimately, however, the presence of a carcinogenic substance in the honey, at even very low levels, could prove economically damaging to the export industry. The other point is that the eradication of Paterson's curse would leave a niche to be filled by more suitable pasture species. The growth of subterranean clover for example would provide an alternative source for beekeepers.

The Victorian committee which reported on Paterson's curse also noted the problems the plant caused the pasture seed industry, because it reduced the production of other seed crops, notably subterranean clover, and made harvesting very difficult because of its woody stems. In addition, the seeds from Paterson' s curse are prohibited from being registered as certified seed in many areas and being virtually impossible to separate from other seeds, that makes farmers understandably very reluctant to harvest seeds from pastures containing Paterson 's curse.

Debate interrupted.