284 



Pests of cacao are the Longicorn heet]es, Macyotoma sp., Acanthophorus 

 maculatiis and Glenea sp., and a Nematode, Heterodera radicicola, the 

 latter being most injurious. This Nematode is also found on coffee, 

 Ageratiim conyzoides and Urena lobata. At Eala it occurs on three 

 species of cacao and their cultural varieties, whilst elsewhere it also 

 attacks Hevea. The relative resistance of the cacao plant stands in 

 relation to the facility for the more or less continual output of 

 superficial roots. The dieback disease must be considered as secondary 

 to Nematode infestation of the roots. The various remedial measures 

 advocated by other authors are reviewed. Trap crops have not 

 proved effective, at least under such climatic conditions as exist at Eala. 



The chief pests of Urena lobata are Dysdercus nif^rofasciatus, D. 

 melanoderes and D. fasciatus. A list is given of the other insects found on 

 this crop. Hand and net collection are advocated for their destruction . 

 A Proctotrupid is recorded as parasitising the Coreid, Anoplocnemis 

 curvipes, F., and the method of parasitism is described. The author 

 does not consider the country suitable for producing silk on a commercial 

 scale, partly owing to the climiate and to the presence of natural 

 enemies of Anaphe spp. and their food-plants. 



Hegh (E.). Les Termites. — Bull. Agric. Con^o Beige, Brussels, 

 xii, no. 4, December 1921, pp. 745-846, 92 figs. [Received 24th 

 March 1922.] 

 In this further instalment of his monograph on African termites 



[R.A.E., A, ix, 521 ; x, 184] the author deals with their feeding 



habits and cultivation of fungi, and the structure and construction 



of their nests. 



Lloyd (LL). The Control o£ the Greenhouse White Fly {Asterockiton 

 vaporariormn) with Notes on its Biology. — Ann. App. Biol. 

 Cambridge, ix, no. 1, April 1922, pp. 1-32, 2 plates, 2 diagrams, 

 5 figs. 

 The earliest adults of Asterocliiton vaporariorum, Westw., were 

 observed in the open on 1st July, and experiments carried out in 

 1919-20 show that this Aleurodid m ay ^ survive a mild winter in the 

 Lea Valley out of doors. Both the eggs and adults are able to with- 

 stand considerable cold, but the intermediate stages are less resistant. 

 Eggs and feeding larvae on severed foliage shrivel up and die with 

 the drying of the foliage. Under these conditions it is evident that 

 the occasional occurrence of severe winters, when all the foHage except 

 that of evergreens is cut down, must exterminate this species out of 

 doors. The" preferred food-plants are tomato, potato, cucumber, 

 vegetable marrow, French beans, tobacco, hollyhock. Calceolaria, 

 Dahlia, hehotrope and stinging nettle. It can also breed on grape- 

 vine, Fuchsia, Calla, Begonia and Geranium, but the mortality of 

 the larvae on these plants is great. It is chiefly of economic importance 

 as a pest of tomatos, and the growing of these plants to the exclusion 

 of other crops is a useful precautionary measure against infestation. 

 The average number of eggs laid by one female is about 130, and the 

 rate of oviposition averages about three a day. On smooth leaves 

 the eggs are laid in circles, but on hairy leaves, such as those of the 

 tomato, they are scattered in groups, almost invariably on the lower 

 surface. In the open the incubation period is prolonged during cold 

 weather, the longest record being 117 days. During August at a 

 mean temperature of 58° F. the shortest period was 13-16 days outside, 



