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LANTANA IN CEYLON.
BY
T. Petch
Peradeniya, Ceylon.
In Memoirs of the Department of Agriculture in India, Vol. V, No. 6, Rao Sahib Y. Ramachandra Rao has presented a paper on Lantana insects in India which is of interest to botanists, as it includes a comprehensive account of the host plants, one at least of which, Lantana aculeata, is a troublesome weed in many parts of the Eastern Tropics.
As regards the status of Lantana, Ceylon constitutes an exception to the general experience. In Ceylon, Lantana aculeata is common enough, but it is not looked upon as a troublesome weed. Indeed, the tendency is rather to regard it as beneficial, since it rapidly takes possession of waste ground and thereby prevents denudation or deterioration of the soil by exposure.
Ceylon, however, comes in for special consideration by investigators of the Lantana problem, as the possessor of a plant, Tithonia diversifolia, which is alleged to kill out Lantana. This idea appears to have originated about 1890, and it was given currency outside Ceylon by Mr. John Ross, a resident in Hawaii, who published a note on the subject in the Planters' Monthly (Bonolulu), vol. X, pp. 436, 437 (October, 1891).
Mr. Ross had met Lieutenant-General Sir Allen Johnson "of the British Army in India" and, on explaining to the latter how " Lantana was fast getting a ruinous control of the best pasture lands," was informed by him that in Ceylon "they were having a similar experience to us, but that lately they were getting it under control through the agency of a particular kind of sun-flower imported there." In consequence, Mr. Ross communicated with Ceylon, and obtained seeds of the sunflower in question, accompanied by a letter from Trimen, from which the following extract was published (loc. cit.).
"The plant referred to by Mr. Ross is, no doubt, the Californian sun-flower, Tithonia diversifolia, the brilliantly yellow-flowered weed so conspicuous on waste ground in Ceylon.
"I have recently pointed out to several visitors here the curious fact that, when growing along with Lantana, this gradually kills out
