132 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



purpose of noting the control of insect pests on citrus trees by means 

 of natural enemies. 



The princzpaZ pest of these trees is the orange white fly (there are 

 others besides). It is most abundant, propagates rapidly, and lives on 

 many non-citrus plants. It encourages the growth of black blight. 

 The purple and other scales are also prevalent. 



The principal enemies of the white fly are certain fungi, while scale 

 insects are also attacked by enemies of the same class. 



The most important of the former is the Eed Aschersonia. This 

 fungus in full possession of a tree badly infested with white fly is a 

 most remarkable and conspicuous sight. The degree of control of the 

 white fly by the fungi is surprising. On some trees 93 per cent, to 

 98 per cent, of the flies were killed, and in most groves the proportion 

 was higher than 60 per cent. 



The fungi achieve much under strictly natural conditions, but still 

 more when these are supplemented by intelligent artificial measures, 

 by which means also time is saved (six to eight weeks being sometimes 

 gained). There are growers who make a business of supplying the 

 spores of the fungi, ,and of applying them where required. — G. H. L. 



Flower Colours. Miss M. Weaver .{U.S.A. Hort. Soc. Iowa, 

 xlv. p. 310, 1911). — Notes the infrequency of blue flowers in families 

 where yellow, red, and magenta occur freely. — A. A. K. 



Flowers in Winter in Algferia. By H. Gay (Rev. Hort. de 

 VAlgerie, p. 116, April 1911). — An attractive list of the flowers which 

 may be enjoyed on the Algerian coast during the winter months. The 

 owner of a small garden at Surcouf gives a long list of blooms which 

 may be gathered in January there, and as the result of recording the 

 number of varieties which he observed in the course of each month 

 during several years he gives the following as the average numbers : 

 January, 21; February, 23; March, 29; April, 32; May, 36; June, 40; 

 July, 35; August, 27; September, 17; October, 19; November, 19; 

 December, 20.— Af. L. H. 



Forcing" by Injection. By F. Weber {Oestr. Gart. Zeit. 

 vol. vi. pt. vii. pp. 241-5; 2 figs.). — A new method of forcing plants 

 consists in pushing a needle into the centre of the base of the bud ; 

 a better result may be obtained by injecting a small quantity of water 

 at the temperature of the room into the bud at its base. Twigs of 

 Syringa vulgaris treated in this way on December 15 began to open 

 their leaves on December 26. Each leaf bud on a stem must be 

 injected to bring the whole into growth. — S. E. W. 



Forcing" by Injection. By F. Jesenke {Oestr. Gart. Zeit. 

 vol. vi. pt. viii. pp. 281-5; 3 plates). — The period of winter rest can 

 be appreciably shortened by injecting water or aqueous solutions of 

 alcohol or ether under a pressure of one to three atmospheres into the 

 bi'ajiches of shrubs. Robinia Pseudacacia gave the best results with a 



