Ferdinand von Mueller

1

Letter not found. For the text given here, see Australasian, 20 June 1885, p. 156 (B85.07.03): ‘The Minister for Agriculture recently received a letter from Mr. Charles C. Watt, of Albert-street, East Brunswick, with reference to the complete extirpation of the phylloxera in the Geelong district. He suggested that all the infested ground should be sown with a plant called pyrethrum, and that when the plants attained a considerable size they should be dug down. Mr. Watt expressed the opinion that if this course were adopted, all insects which came within some feet of the plants would be killed. He suggested that a supply of seed might be procured from the Ovens district, where he saw the plant keep free from blight cabbages which were planted within 3ft. of it. The matter was referred to Baron Von Mueller, the Government botanist, who has furnished the following report’. See also M to G. Berry, 13 July 1885 (in this edition as 85-07-13a).

D. E. Martin, Esq.,

Secretary of the Department of Agriculture.

Sir,—

In compliance with the request of the Minister of Agriculture I have the honour to state that in my opinion the suggestion of Mr. Charles C. Watt, to raise the insecticidal pyrethrums (or chrysanthemums) on land cleared of vines affected by phyllozera vastatrix, is worthy of trial, though it will perhaps be difficult to prove whether the migrating insect would really always be intercepted and destroyed by these pyrethrums, which herbs, however, were already introduced into Victoria many years ago by myself, experimentally. The idea set forth by Mr. Watt is not altogether a new one, for in the last edition of my work on Select Plants for Industrial Culture and Naturalisation I remarked already, in the article on ‘Vitis Vinifera’:— ‘The cultivation of insecticidal herbs to check the ingress of phylloxera should be more extensively tried, as such plants might ward off the insect, at all events, in a wingless state.’ Insecticidal herbs, of which there are many, including even the ordinary hemp and potato, may be effectual in arresting the migration of the phylloxera above ground, but whether this effect would reach likewise sufficiently far beneath the ground, where the insect colonises even at considerable depth, also needs yet to be ascertained.

The total subduing of phylloxera on remnants of vine-roots, which is an object at present sought to be attained in Victoria, seems to be surrounded with extreme difficulty, if it requires to be forced within a limited period, for it will likely be found next to impossible to remove from any spot the last particles of vine-roots, on which still some individuals of the insect may lodge, by any mechanical operations ever so carefully planned and carried out, or to reach all such bits of vine-roots by chemical agencies within the needful space within a given time and within reasonable expenditure, however recommendable any effort in that direction undoubtedly must be. Hence, after all, the danger of multiplication of the insect may insidiously and unobservedly continue after the ground is allowed again to be given to vine-culture; and, in my opinion, it would therefore be far safer to rear insecticidal, or indeed, any other, plants than to replant the vine itself, which possibly at once may become a new nidus of infection.

Melbourne, July 13, 1885.

2

At the end of M's letter, the report concludes: ‘It has been decided to obtain sufficient seed to plant half an acre as an experiment.’