17 



Prickly-pear growth," but suggested " procuring 

 specimens of the cochineal insects, and making 

 experiments. ' '* • 



_ The specimens of "Wild Cochineal Insect," 

 which Mr. Thurston named Coccus cacti, var. 

 Grana sylvestris, were accordingly obtained 

 from Ganjam and handed over to Dr. A. G. 

 Bourne (now Sir Alfred Bourne), Professor of 

 Biology, Madras University, who tested their feed- 

 ing habits on "a clump of the yellow-flowered 

 Prickly-pear {Opuntia dillenii), and on plants, 

 secured from the Horticultural Society's Garden, 

 of the red-flowered species (Opuntia (Nopalea) 

 cochinelifera) , and three other species (0. decu- 

 mana, 0. monacantha, and 0. spinosissima) . The 

 specimens sent were all attached to the red- 

 flowered Cactus (0. cocMnellifera) ." Dr. 

 Bourne, however, arrived at negative results. The 

 brief report embodying his findings is entitled 

 " Destruction of Prickly Pears with the aid of 

 the Cochineal Insect or other Parasites, "t 



On interviewing Sir Alfred Bourne at 

 Madras (on 26th January, 1913), it was elicited 

 that he was not able to add to what he had written, 

 nor to definitely identify the Opuntia spp. that 

 has been used in his experiments. 



The foregoing statements indicate that in 

 Southern India three things had been early 

 brought about: — (1) A plant (one of the Prickly- 

 pears, Opuntia, sp.), having the ability to spread 

 freely and already occurring in several localities, 

 was widely disseminated, and its development and 

 increase encouraged; (2) an insect especially par- 

 tial to it was similarly propagated; and (3) the 

 destruction of the former^ by the latter occurred 

 whenever and wherever they became associated. 

 Also, that in more recent times (1862-1872) the 

 last event was apparently not always realised. 



During the extended travelling in Southern 

 India only a single instance of the occurrence of 

 Opuntia monacantha growing at large came 

 under notice. This was afforded by the discovery 

 of a few plants growing isolatedly near Grund- 

 lupet, at the extreme south of Mysore. Again, 

 to the various Government officials that were 

 consulted in Madras, Bombay, and Mysore, 

 Opuntia monacantha, as a locally-growing plant, 

 was apparently unknown. Special inquiry 

 amongst intelligent ryots was equally fruitless 

 in bringipg a growing plant to light. Nor were 

 specimenis included in the Herbaria attached to 

 the Poona, Bangalore, and Coimbatore Agricul- 

 tural Colleges. However, M. Punchapicasa Iyer, 

 the District Forest Officer of the Western Circle, 

 Coimbatore, mentioned, as growing at the Thada- 



* Vid, Proo. Board of Revenue, Madras, Res. No 

 135, 17th June, 1896 ; and E. Thurston's Report, dated 

 15th June, 1896, published (pp. 2 and 3) therein ; also, 

 Proe. Board of Revenue, Misc. No. 3844, 4th Aug., 1896. 



t Administration Report, Madras Government 

 Museum, for the year 1897-1898. Appendix J., op. cit., 

 pp. 28-29. 



t One member of the Commission (Tryon, 1910) has 

 pointed out that this was Cactus indious, Roxburgh, 

 and followed others in erroneously identifying " indicue " 

 with Ha worth's Opuntia , dillenii, instead of pointing out, 

 as I. H. Burkill has since done (1911), that it was only 

 another name for Opuntia monacantha Haw. Burkill has, 

 moreover, accumulated abundant evidence in support of 

 the conclusion that this plant — in India, at least — is its 

 exclusive host plant, the Manila Opuntia mentioned in the 

 " Asiatic Register" and elsewhere as " one which the Wild 

 Cochineal Insect would eat" not being identifiable. 



gam Eeserve, 15 miles away, a few bushes of a 

 species of Prickly-pear distinct from Opuntia 

 dillenii and which apparently was referable to 

 this species. 



Hence it may be inferred that the species 

 once common in Southern India and so freely 

 distributed to many districts by Dr. Anderson 

 in the eighteenth century, as has been already 

 mentioned, is now on the verge of extinction 

 there. 



Its virtual extermination may, therefore, be 

 attributed to the insect referred to; the insect 

 becoming rare as its host plant has become rare. 

 The failure of the Coccus to act as a cacticide is 

 accounted for by its not being confronted with 

 its proper host plant — Opuntia monacantha. 



Burkill (1911, pp. 318-9) may be quoted as 

 confirming this conclusion: — " The Wild 

 Cochineal Insect introduced into India in 1795 

 spread so rapidly on Opuntia monacantha as to 

 destroy it, branch and root, out of the country- 

 side. The insect was introduced into both 

 Bengal and Madras, but, owing to the action of 

 the Government of Madras in encouraging its 

 propagation, it spread more rapidly there than 

 in Bengal. It had almost done its work of 

 destruction in Southern India in twenty years. 

 . ^ . . Opuntia monacantha, thanks to the 

 Cochineal Insect, which is still with us (referring 

 to its occurrence in Northern India), is now a 

 comparatively scarce plant." 



Referring to species of Prickly-pear other 

 than 0. monacoMtha that are now endemic in 

 India, Burkill expresses a hope "that his work 

 will prevent any waste of money in fruitless 

 attempts to destroy Prickly-pear by means of the 

 Cochineal Insect; such attempts as have been 

 made in the past have been made in ignorance of 

 the true food plants of that little insect. ' ' 



As already mentioned, the " Punjab 

 Opuntia," which closely resembles one of the 

 Queensland pest pears, is not affected by the 

 parasite. Moreover, it is known that none of the 

 following species is attacked by it in India : — 0. 

 nigricans, 0. dillenii, and 0. decumana; while 

 the Commission's attempt to infect 0. dillenii 

 experimentally at the Henaratgoda Gardens in 

 Ceylon has not succeeded. 



With reference to the insect itself, Mr. E. 

 Green, the Entomologist to the Government of 

 Ceylon, has pointed out that this " Wild Cochi- 

 neal Insect" attached to Opuntia monacomtha in 

 India, and that he named in 1908 Coccus indicus, 

 Green, is identical with the one now occurring in 

 Ceylon on a plant that he erroneously identifies 

 with Opuntia dillenii, but that is actually, as we 

 have seen, the same as its Indian host plant 

 (1912). 



The interest of the foregoing remarks consists 

 in the fact that Opuntia monacantha is one of the 

 Prickly-pear pests of Queensland (Suttor Biver 

 and Bockhampton) , and occurs in New South 

 Wales, Victoria, and South Australia also. The 

 insect spoken of was despatched in quantity 

 by the Commission from Ceylon to the first- 

 named State, where it should accomplish, in 

 destroying Opuntia monacantha, what has been 

 enacted through its instrumentality in British 

 India as well as in Ceylon. 



