43 



at Teneriffe and Grand Canary. It was found 

 growing wild in many places in both of these 

 islands, more especially in ^e latter. It was 

 observed to have the outer petals of its flowers 

 commonly rufous, especially when growing in 

 drier situations, as near Las Palmas, in the latter 

 island. On the high ground to the west of the 

 latter city, this Prickly-pear was found possessing 

 small shortly-pyriform, deep-purple fruit re- 

 sembling that of the commoner Gayndah (Queens- 

 land) Prickly-pear that has, too, been regarded 

 as a form of the species under notice. 



0. monacantha, Haw., was observed only on 

 Teneriffe, and appeared to occur quite locally at 

 a spot near Laguna. 



0. tomentosa, Salm-Dyck. — This tall dark- 

 green velvety species was observed near Orotava. 

 as well as in isolated localities in the north of 

 Grand Canary. 



The time at the disposal of the Commission 

 for investigations in the Canary Islands being 

 necessarily short, only a limited survey was 

 practicable. 



The facts regarding the prevalence of 

 Prickly-pear (0. ficus-indica) on the two islands 

 visited confirmed the opinion formed from the 

 investigations in South Africa — that there is 

 grave danger that, under the conditions of soil 

 and climate existing in Queensland, especially in 

 the Central district, plants belonging to the 

 varieties included under the abovenamed species 

 may become widely spread and constitute a very 

 formidable pest. Our experience in the Hawaiian 

 Islands also confirms that opinion, since, in Oahu, 

 a species closely resembling the " Westwood " 

 pear has become firmly established. Hence those 

 growing at large in. the Eoekhampton area should 

 receive the attention of the authorities. 



NATUEAL ENEMIES. 



Disease. 



No individual plants of any of the several 

 kinds of Prickly-pear mentioned as growing in 

 these islands were observed to be dead or even 

 dying as the outcome of disease of any kind, 

 parasitic or otherwise. In certain limited areas, 

 where the climate was more arid, many had failed 

 to thrive; a remark that especially applies to 0. 

 ficus-indica and 0. rohusta, and even to 0. dillenii, 

 which is able to withstand very dry conditions. 



Our inquiries as to the occurrence of local 

 Prickly-pear maladies were equally barren of re- 

 sults. Owing to their temporary absence it was 

 impracticable to interview two of the authorities 

 on Grand Canary, who, is was expected, might 

 throw light on this question ; but the districts m 

 which they respectively reside were traversed 

 and inspected with negative results. 



Insect Enemies. 

 The insects noticed feeding on Prickly-pear 

 were : — 



1 The common widely-distributed Opuntia 

 Scale Insect {Diaspis, sp.), already met 

 with in the Brisbane district. This was 

 observed on the single plant (0. robusta) 

 at Orotava, and evidently produced little 

 ill-effect on its host, 



2. Opuntia Aphis found on a plant of the 



species named, growing near Orotava 

 also. • It was restricted to the tender 

 shoots and flower buds, but apparently 

 inflicted no noticeable injury. This in- 

 sect is apparently identical with one 

 already met with by a member of the 

 Commission on 0. incrniis at Westwood 

 and Goondiwindi, where also its presence 

 is unattended with ill-effect to the plant. 

 It apparently is referable to a species 

 that is not restricted to a single host, as 

 happens with so many kinds of Aphidse. 



3. Precious Cochineal Insect (Coccus cacti, 



Linn., typical) .■ — The species of Prickly- 

 pear on which this insect will thrive 

 having been already introduced to the 

 Canary Islands for the sake of its fruit, 

 the Precious Cochineal was imported in 

 1826 (Benitez, 1912, p. 17c) and estab- 

 lished upon it. This importation led to 

 the creation of an industry which for a 

 time, at least, was most important. 

 However, in some districts its introduc- 

 tion was opposed, notably at Guimar, 

 Teneriffe (Barker-Webb and Berthelot, 

 1840, pp. 208-9 ; Lowe, 1868, p. 316), for 

 the alleged reason that the insects 

 destroyed the crop of fruit through ren- 

 dering the plants sterile. It was sought, 

 then, to discover to what extent the 

 Precious Cochineal Insect injured the 

 Prickly-pear plant with which it was 

 associated; but, although apparently 

 stunting it and retarding its growth to a 

 small extent, the injury due to its pre- 

 sence was almost unappreeiable. Some- 

 times, in spots where the insects had 

 densely congregated, there occurred a 

 dark and more or less superficial dis- 

 coloration. This absence of injury was 

 noticed in cases where insects lived in 

 the open and had spontaneously distri- 

 buted themselves amongst plants growing 

 uncared for, as well as when it existed 

 in Nopalries, where both it and the host 

 plants were sedulously looked after, and 

 where the insect, indeed, had developed 

 to such an extent as to whiten the 

 Opuntia with which it had become 

 associated. However, the Precious 

 Cochineal Insect, even were it injurious 

 to the Pricklj'-pear, is restricted in its 

 dietary to certain species, amongst which 

 the Queensland "pest species " are not 

 included. 

 Wild Cochineal (Coccus, sp.). — None of 

 the insects coming within the definition 

 of Grana sylvestre was observed. 



UTILISATION. 

 No instance of the prosecution of any 

 procedure for utilising the Prickly-pear involving 

 its destruction came under notice. Available 

 literature relating to the Prickly-pears of the 

 Canary Islands makes no mention of any such 

 employment. Dr. G. V. Perez, of Orotava, Tene- 

 riffe, stated that locally in the drier regions, 

 where very little water was available. Prickly- 

 pear (0. ficus-indica) was used as a food for 

 cattle, the few spines present being rubbed off or 

 removed by singeing. It, at least, was found tq 

 keep alive cattle that received it. 



