no 



A serious disease — a wliiti* rot — caused by 

 Sderoiium cactorum has been described as occur- 

 ring iji Argentina during the winter. Many 

 species of Sclerotium are not confined to one host- 

 plant. Its introduction is not at present reeom- 

 171(^11 dod. 



A great deal of destruction of Prickly-pear 

 was seen to be occasioned in certain parts of 

 Argentina by the larvae of moths, one of which 

 is the Argentine moth-borer Zophodia cactorum, 

 while the other — the Mendoza moth-borer — has 

 not been identified by the Commission thougli 

 apparently related to the former. Both of 

 these are capable of attacking several species of 

 cactus, including some Opuntias naturalised in 

 Queensland, and their food supply appears to be 

 restricted to that family of plants. The former 

 occurs in Uruguay and the adjacent regions of 

 Argentina, while the latter is found commonly 

 in the country surrounding Mendoza, on the 

 Andean foot-hills. A small number of larvae of 

 the former, bred out during the voyage and free 

 from parasites, were brought to Brisbane by the 

 Commission, but most of them have since died. 



A considerable destruction of young plants 

 is caused by other insects in Bahia as well as an 

 Argentina, but the results of their attack are 



insignificant when compared with those just 

 mentioned. 



The Hemiptera — plant bugs and various 

 coccids — do not appear to be sufficiently injurious 

 to warrant the labour which would be necessary 

 to introduce them from South America. How- 

 ever, both the Brazilian and the Argentine species 

 of Wild Cochineal have been transported to this 

 State. The latter died about the time of arrival 

 owing to their inability to feed upon the species 

 of Prickly Pear offered to them after the death 

 of their proper food plant. The Brazilian Coccus 

 has established itself here on young growing 

 plants of its host species, the "spiny palmadora" 

 of Bahia. 



Cactus plants are not utilised in South 

 America in any manner (except for feeding stock) 

 which would be of service in Queensland in 

 destroying them. The feeding of cacti to stock is 

 carried out only during times of scarcity. 



Destruction of Prickly-pear by an over- 

 growth of a certain quick-growing grass has been 

 suggested. In the north of the continent, a climb- 

 ing leguminous plant is used, and when the 

 Opuntias are quite overgrown, the climber is cut, 

 allowed to dry and then set on fire, the Prickly- 

 pear becoming badly scorched. It is suggested 

 that a repetition of the operation would quite 

 destroy the cactus. 



X. HAWAIIAN ISLANDS. 



The Commission stayed for a fortnight on 

 the island of Oahu, awaiting a steamer en route 

 to Sydney from San Francisco. 



Pricldy-pear was seen to be abundant in 

 certain rocky parts of the island, especially near 

 Honolulu and Haleiwa. In places the growth was 

 found to be quite dense, especially on rocky hill- 

 sides and other localities unsuited for agriculture, 

 as well as in certain dry areas. This was due in 

 part to the fact that the land was not being 

 utilised and in part to the absence of any con- 

 trolling agents. 



The species which is locally called 0. tuna 

 (Hildebrand, 1888, p. 140) reminds one of the 

 " Westwood Pear" of the Rockhampton district 

 in Queensland. There are two varieties, the 

 fruit of the red fruiting kind being eaten by the 

 native population. The plants reach a height of 

 10 or 12 feet, and may assume a tree-form by 

 the removal of the lower branches, or they may 

 remain more or less shrubby. The greyish joints 

 are sometimes small but generally very large, 

 reaching about 14 inches in length by about 7 in 

 width, though it is by no means uncommon to 

 see segments nearly 2 feet in length by 15 inches 

 in breadth. They are almost symmetrical. There 

 are eight or nine areoles in oblique series, each 

 bearing from one to seven white twisted spines 

 arranged in a radiating manner, three or four of 

 them being usually nearly an inch in length. 

 The spinules are reddish-yellow or reddish-brown. 

 The spines vary considerably in number and size 

 on segments of the same plant or on different 



areoles of the same joint. Young as well as 

 mature joints are often spineless, or almost so. 

 The stems are spiny. 



The flowers are orange, the fruit (in the 

 edible variety at least) being large and plump 

 with dark red skin and pulp resembling the fruit 

 of certain varieties of 0. ficus-indica as well as 

 the Mexican "Cardona," 0. streptacantha, 

 though it is much larger than the latter. New 

 joints are produced laterally from the edge of 

 older segments in a manner similar to the 

 Queensland pear already referred to. 



The plant differs from our "Westwood or 

 Red Mexican ' ' species in possessing a larger and 

 more cylindrical fruit; a less distance between 

 the areoles ; and the segments rather thinner and 

 less rounded. Some plants, more especially the 

 relatively spineless forms, remind one very much 

 of the Mission Pear of Mexico and Southern 

 United States, and the Indian Pig of the Medi- 

 terranean coasts. 



The species is evidently near 0. streptacan- 

 tha, Lem., or 0. chavcna, Griff., and is certainly 

 not the same as the 0. tuna, L., which Drs. 

 Britton and Rose have identified as the common 

 Jamaican species, a low-growing, straight- 

 thorned form allied to 0. diUenii. Schumann, in 

 his monograph (1899, p. 723), did not differen- 

 tiate the two species, but included both under the 

 name 0. tuna, Mill. 



Hildebrand refers to another species which 

 he thinks may be 0. tomentosa, S.D. 



