546 



utterly impracticable, and it is possible that vast swarms developing 

 there in the present cycle may sweep far down into the Union of South 

 Africa ; but it seems not unlikely that the infestation of the desert 

 is largely dependent on swarms that migrate there from settled parts 

 and that in combating the pest in cultivated regions the danger of 

 invasion from the desert is greatly minimised. In all, 28,000 swarms 

 were destroyed over an area of 20,000 odd square miles in the present 

 campaign ; some 10,000 gallons of poison and 3,556 spray pumps 

 were issued, the total cost of the campaign amounting to about £10,000. 



Cyrtacanthacris septemfasciata (red locust) is another migratory 

 species that is liable to cause devastation in South Africa, and though 

 this species has not given any trouble in the Union for a number of 

 years, it is a significant fact that twice before in the last century 

 invasions of the red locust followed close upon those of the brown, 

 the one chiefly devastating the coastal belt and the other the interior ; 

 it is therefore rather to be expected that the red locust will soon again 

 give trouble. 



Phylloxera has been introduced on Cape grafted vines and has 

 evidently been present for six years or more. It occurs in a number 

 of widely separated districts, but is of so little importance that its 

 extermination is not considered worth attempting. The eucalyptus 

 borer is another introduced insect that is likely at any time to become 

 prominent. Until recently this Longicorn beetle was erroneously 

 known in South Africa as Phoracaniha recurva, Newm., its correct 

 name being P. semipunctata, F. Sickly trees, or those that have 

 been felled and left lying with the bark on, are attacked between the 

 bark and the sap-wood, the tissues being eaten away for many feet 

 together until the tree may be killed. The eggs of the borer are found 

 to be parasitised in the south-western districts of Cape Colony. In 

 Australia it is known to have a number of larval parasites and their 

 introduction into South Africa has been planned for several years, 

 but has not materialised owing to the War. 



The Indian cochineal insect, Dactylopius (Coccus) confusus indicus 

 is eradicating with astonishing rapidity the Monocantha prickly pear 

 [Opuntia monocantha], especially in Natal. This species is closely 

 allied to the true cochineal insect, D. coccus (C. cacti), and still more 

 closely to the Cape species, D. confusus capensis, which has infested 

 the prickly pear in South Africa for nearly a hundred years without 

 any injurious effect. A small colony of D. indicus was brought to 

 South Africa in 1913 by the Queensland Prickly Pear Commission 

 and already nothing but a few dried stumps remain where there were 

 formerly veritable walls of this plant ; this is an extraordinary fact, 

 since both the insect and the plant originally came from South 

 America where it is presumed they must exist together. 



The results of investigations into the life-history and habits of 

 several common insect pests, including Bagrada hilaris, Colias electra 

 and PluteUa maculipennis, will be published in special reports. A 

 Longicorn, Phryneta- spitiator F. (fig borer) and Enarmonia batracJiopa, 

 Meyr. (false codling moth) are also being studied. Important work 

 has been done in the study of the scale-insects and the termites of 

 South Africa. It is hoped to facilitate the cyanide fumigation of 

 plants by introducing liquified hydrocyanic acid, which volatilises 

 almost instantaneously when exposed to air, producing gas without 



