95 



At a spot along the new road there were seen 

 a few priekly-pear plants (0. dillenii) that had 

 almost succumbed to some illness, the following 

 features being exhibited bj^ them. Individual 

 branches of the affected plant were dying back, 

 as might happen were some root trouble present. 

 The terminal stem-joints were apparently the 

 first to become injured. Those on which the 

 disease was noticed presented the following symp- 

 toms : — Pale yellowish patches had arisen, having 

 an irregular waved, outline, well marked on the 

 general green surface. Within these altered areas 

 that would gradually involve the entirely stem- 

 joint, grey, more or less circular, blotches ap- 

 peared, and these had sprinkled over them minute 

 black specks, the reproductive organs of some 

 epiphyllous fungus. Ultimately the entire sur- 

 face became mottled with grey and pale olivace- 

 ous brown. In addition there was present another 

 fungus with the fruiting bodies exceptionally 

 large and more widely separated; also a third 

 fungus sparingly developed, resembling that asso- 

 ciated with Zone-spot Disease. Some or all of the 

 organisms were probably saprophytic. Notwith- 

 standing the presence of these features, the stem- 

 joints remained alive for a while without produc- 

 ing any new growth; but in those in which the 

 trouble had proceeded to its full length, the 

 internal tissue had died, disintegrating into a 

 semi-liquid pulp, only the fibrous skeleton re- 

 maining intact. Specimens submitted to micro- 

 scopical examination exhibited no additional 

 features such as might thr6w light on the etiology 

 of this prickly-pear malady. 



ST. THOMAS. 



This island, whose annual rainfall is com- 

 paratively low, has evidently been cultivated to 

 a much larger extent formerly than at present. 

 This may account for prickly-pear plants not as 

 yet occupying the flats near the coast and for 

 their occurrence elsewhere as isolated plants only. 

 0. dillenii and 0. cataccmtha occur along the sea- 

 board and on the arid foothills overlooking it, 

 the central mountain ridge extending ea^t and 

 west being devoid of prickly-pear. 



In addition to the species mentioned, 0. 

 curassavica,, var. Taylori is very common, often 

 extending in the direction of the roads, as might 

 be expected from its portability owing to the 

 readiness with which it becomes attached to stock. 

 It usually occurred on the steeper stony slopes. 

 It is distinguished from 0. triacantha (Willd.), 

 DC. (0. spinosissima, auct.) in possessing spmes 

 which when young are reddish-purple, not lemon- 

 yellow. 0. cataccmtha, the tree-like Opuntia, 

 grows on the steep rocky foreshores at the south- 

 east .extremity. Nopalea cochinelifera was found 

 exclusively in the precincts of dwellings. 



Investigation was prosecuted along the south 

 coast, throughout the central elevated country, 

 and at the eastern extremity (Smith's Bay). 



Disease Occurrence. 



The plants seen were not affected by any 

 natural enemy except in the case of 0. taylori, 

 that occasionally harboured Diaspis enchinocacti, 

 but with little injury to itself. 



THE VIRGIN ISLANDS (TORTOLA, VIRGIN 

 GORDA, AND ANEGADA). 



1. TOBTOLA. 



The parts of this island visited were the en- 

 tire southern seaboard, the western extremity, 

 and the portion of the central mountain ridge 

 lying east of the town of Broad Town. Gener- 

 ally speaking, the island is made up of rather 

 steep declivities, the level area being compara- 

 tively small in extent. Although its, rocky 

 nature would suggest its unsuitability for agri- 

 culture, the soil is good and the island was for- 

 merly almost entirely devoted to agriculture 

 (cotton, sugar-cane, &c.). 



The kinds of prickly-pear found growing on 

 it were — (1) 0. dillenii; (2) 0. catacantJm (both 

 spineless and spiny forms) ; (3) 0. curassavica 

 var. Taylori; and (4) a natural hybrid between 

 Nos. 1 and 3. Of these, the first was prevalent 

 throughout the coastal region, usually forming 

 isolated patches, and competing with the second 

 for a decidedly maritime location as a site for 

 abode, especially along the southern coast, where, 

 erecting its tall stem amongst the debris at the 

 bases of the steep rocky escarpments, it was 

 almost laved by the sea. 0. taylori was exceed- 

 ingly common in the lower foothills, growing 

 almost everywhere and often forming an impedi- 

 ment to walking owing to its readily detachable 

 stem-joints armed with long, stiff, penetrating 

 spines. 



Disease Occurrence. 

 The Commissioner (the Hon. Leslie Jarvis), 

 the Agricultural Instructor (Mr. C. Pishlock), 

 and Mr. J. P. Romney, an agricultural settler of 

 long standing, deposed that they had not noticed 

 any natural enemy, either disease or insect, asso- 

 ciated with prickly-pear plants at Tortola. Per- 

 sonal investigation led to the same conclusion 

 with this exception: that some plants of 0. dil- 

 lenii were damaged by the Zone-spot malady, 

 more particularly referred to in dealing with 

 observations at Antigua. In the different patches 

 of the natural hybrid between this pear and 0. 

 taylori examined, no instance of the occurrence 

 of this disease was remarked. 



2. Anegada. 

 This small coral island, measuring about 10 

 miles in length, and elevated but a few feet 

 above sea-level, is situated about 38 miles from 

 Broad Town, Tortola. It is difficult of approach, 

 being almost surrounded by dangerous reefs. ■ 0. 

 dillenii occurs abundantly on it in a more or less 

 sporadic manner, especially near the settlement, 

 its fruit being gathered as food for pigs. 



Disease Occurrence. 

 Growing under conditions so peculiar, for some 

 of the plants seemed to spring ahnost from the 

 bare level, coral rocks, arising as they did from 

 mere soil-filled chinks in them, it was expected 

 that a special disease might be mduced. How- 

 ever two known diseases were alone met with, 

 viz Prickly Pear Anthracnose or Shot-hole, and 

 Zone-spot Disease. The latter had apparently 

 exercised some check on the plant it had attacked, 

 but generally speaking, natural enemies had had 

 little influence in controlling its spread, condi- 

 tions of growth being alone adequate to accom- 

 plish this. 



