Ferdinand von Mueller

1

Letter not found. For the text given here, see 'Board of Agriculture. Thistles', Argus, 24 September 1862, p. 7 (B62.14.01). In presenting the report to the Council of the Board of Agriculture, M 'explained at some length the nature of the experiments which had been made by the committee' and recommended that 'in order to further test the qualities of the specific, and to ascertain also the probable cost of practically effecting the destruction of thistles, an acre of them, of old growth, should be operated upon under the supervision of the council, and that the costs of such further experiments should be borne by the board'. After discussion, these recommendations were adopted.

The Sub-Committee of the Board of Agriculture, appointed to ascertain the efficiency of Mr. Patrick Hayes's method of destroying the thistles, met twice at the ground adjoining the terminus of the Melbourne Railway Company. First, on the 5th September, in order to witness the application by Mr. Hayes of the liquid, proposed to be employed for the extirpation of thistles. A number of dwarf plants, as well of the spear thistle as of the spotted thistle, had the liquid applied to them, in some instances in a concentrated state, in other instances half diluted with water. The sub-committee met again on the 10th inst., when promiscuous specimens of the plants operated upon before were examined. It was found that the liquid had drawn by capillarity from the parts touched downwards into the roots, and this to a greater or less extent, according to the quantity employed, but, seemingly, in all cases sufficiently to destroy the vitality of the root.

The sub-committee, while thus far recording their impression that Mr. Hayes's liquid must be regarded as a very efficient agent for the destruction of the thistle plants, wish to state that all the plants experimented upon on these preliminary occasions were of dwarf growth, sprung from the seeds shed in the previous autumn, and that, consequently, the liquid had a most ready access to their roots. It appears, therefore, recommendable that the experiment should be repeated for the purpose of ascertaining positively the following points:—

1. At what a cost of material (diluted or undiluted) could one acre of ground, considerably overgrown with thistles, be cleared of this weed in adopting Mr. Hayes's method?

2. What practical difficulties may exist in the way of manipulation, when the liquid is to be employed on an extensive scale, and what cost of manual labour will it entail for eradicating the thistles thus on one acre of ground?

3. To what extent may the absorption of the liquid be impeded, should it prove generally difficult to obtain full access to the roots, whenever the thistles have obtained a considerable size, and when, in consequence of great abundance of thistles in any locality, it may be exceedingly difficult to deal carefully with each individual specimen?

The sub-committee considers it but right to recommend that these experiments should be followed up, since possibly the expense incurred by the application of Mr. Hayes's liquid, added to that of the manual labour entailed, may be well compensated by the surer success in destroying the plants by the application of the liquid, than by the ordinary process of cutting, which, unless carried out to the necessary depth, proves not unfrequently inefficient.