105 



Bhipsalis lorentziana at La Plata (Speg., 

 1910, p. 407) ; Macrophoma phyllocacfi, 

 Speg., on cultivated Phylloeaotus at La 

 Plata (1910, p. 349) ; Pyrenochoeta cerei- 

 cola, Speg., on Cereus haenkeanus in 

 Misiones, North Argentina (1910, p. 353) ; 

 SphcETopsis cereicola, Speg., on Cereiis 

 triangularis cultivated at La Plata (1910, 

 p. 361) ; DidymochcBta opuntiicola, Speg., 

 on fruits of 0. diademata, (N.W. Argen- 

 tina (1910, p. 369) ; Diplodia cerei-trian- 

 gidaris, Speg., on Cereus triangularis cul- 

 tivated La Plata (1910, p. 370) ; Stagano- 

 spora opuntim, Speg., on 0. aurantiaca at 

 Mendoza (1910, p. 372) ; Didymella acan- 

 thophila, Speg., on spines of 0. aurantiaca 

 at Mendoza (1912, p. 53) ; Montagnella 

 opuntiarum, Speg., var. minor, on Bhip- 

 salis lumbricoidis at La Plata, and var. 

 microcarpa on Cereus candicans near Men- 

 doza (Speg., 1909, p. 422; Bosellinia 

 opuntiicola, Speg., on 0. ficus-indica in 

 Argentina (1909, p. 338) ; Ophiochceta 

 cereicola, Speg., on Cereus lamprochlorus 

 salinicola, cultivated La Plata (1902, p. 73) 

 and- on Echinopsis from Santiago del 

 Bstero (Speg., 1909, p. 403; Pyrenochceta 

 spinicola, Speg. (1902, p. 81) on 0. aora- 

 cantha; Teichospora cereina, Speg., m 

 Cereus spegazzinii, cultivated La Plata 

 (1909, p. 396) ; Broomeia congregata, var. 

 argentinensis, Speg., on dead Opuntias in 

 Western Argentina (1912, p. 15) ; Phoma 

 rhipsalidiaola, Speg., on Bhipsalis lorent- 

 ziana— enltiya.ted La Plata (1912, p. 112) ; 

 Uromyces peireslcioe, Diet., on Peireskia 

 sacharosm from Salta, Argentina (Speg., 

 1909, p. 313). 



INSECT ENEMIES. 



The most important insect enemies seen dur- 

 ing the investigations in South America were the 

 two allied moths whose larva bore into the jomts 

 of certain Prickly Pears and other cacti and 

 eventually bring about their destruction. One of 

 these is Zophodia cactorum, Berg. (1885, pp. 

 13-14), belonging to the Phycitidese, the other— 

 "the Mendoza moth-borer "—being not yet 

 identified, though apparently also a Phycitid. 

 Our attention was drawn to the former by Dr. G. 

 Spegazzini, at La Plata. 



Zophodia cagtoeum, Berg. (The Argentine 

 Moth Borer). — The larva when mature is a 

 yellowish or orange-coloured grub about %-inch 

 in length. It has a dark, shining head and there 

 are usually dark, sharply-defined, transverse 

 bands on part of the dorsum of each segment. 

 A rather thin cocoon is spun, generally on the 

 ground under fallen joints. Specimens which 

 were being transported to Queensland by the 

 Commission passed through the pupa stage m 

 about three weeks. The grey moth is about two- 

 thirds of an inch in length and has a wing 

 expanse of from one to nearly one and a-halt 

 inches. Eggs are laid in a long single row 

 which is attached by one end in a similar manner 

 to those of Melitara referred to in the section o± 

 this report dealing with the work m the United 

 States of America (Hunter Pratt and Mitchell, 

 1912, plate 7, fig. 1). 



The young on hatching are very active and 

 begin to bore into the segment under cover of a 

 delicate silky web, many of them entering 

 through one aperture. One or more holes are 

 made and once an entry is gained the fleshy 

 parenchyma of the joint is rapidly eaten, several 

 grubs being usually found at work there. The 

 debris is moist and bright green — ^the colour of 

 the plant pulp — and is rejected through one of 

 the apertures made in the segment. If left to 

 themselves the result of their invasion is the 

 eating out of all or most of the tissues, merely 

 the epidermis being left. The larvae can fre- 

 quently be seen quite readily in the tissues, which 

 become translucent during the attacks. They are 

 very active and travel from joint to joint and 

 begin work again. Berg mentions that the 

 flowers are also attacked. The injury caused by 

 the Zophodia is greatly increased by the invasion 

 of lowly organisms and of scavenging Diptera 

 which breed in the affected joint, the larvae of the 

 latter soon reducing the rest of the tissues of the 

 segment to a dark-coloured fetid liquid which 

 may remain in the dead hollowed-out joint for a 

 long time, as the epidermis forms a bag. 



The insect was noticed at work at La Plata 

 and in the Botanical Gardens, Buenos Aires, 

 during January and February, 1914. No plant 

 other than Cactacese was known to be affected by 

 it. Amongst the Prickly Pears seen to be attacked 

 in these two localities were the following : — 



1. Opuntia quimilo, Sch. — cultivated at La 



Plata. This is an arborescent species 

 with a few long spines indigenous to 

 the North-west of Argentina and allied 

 to the spineless 0. anacantha, as well 

 as to 0. striata, both of which are very 

 closely related. 



2. 0. anacantha. 



3. 0. decumana — cultivated at La Plata. 



4. 0. maxima (= 0. robusta) — a Mexi- 

 can species cultivated at La Plata. 



5. 0- argentina — cultivated at Buenos 

 Aires— allied to and regarded by Schu- 

 mann (1899, p. 657) as identical with 

 the common Southern Brazilian tree- 

 pear, 0. brasiliensis, though Spegaz- 

 zini (1905, p. 508) believes that they 

 are distinct. 



6. 0. mowacanWiffl— cultivated at Buenos 

 Aires. This is one of the Queensland 

 pest pears (Suttor River, Rockhamp- 

 ton, &c.). 



7. 0. chaJcensis, Speg.— cultivated at La 

 Plata. This arborescent species closely 

 resembles 0. striata in regard to its 

 joints. 



8 0. ficus-indica — cultivated at Buenos 

 Aires. This species is widely cul- 

 tivated in Argentina and Chili, parti- 

 cularlv in the drier zones, for the sake 

 of its" fruit (Speg., 1906, p. 512) — 

 hence the suggestion in the " Chronica 

 Agricola" that all parts found to be 

 attacked by the borer should be re- 

 moved and burnt. The Westwood and 

 particularly the Yellow Mexican, 

 Prickly Pears of Queensland are re- 

 lated to this species. 



