712 



Orchard and Bush Fruit Pests. [march, 



and from trunk to roots, especially during the late autumn to the 

 latter, where much woolly aphis winters. The aphis does a great 

 amount of damage to young and old trees, not only by causing 

 deformities and by weakening the plant owing to loss of sap, 

 but also because trees attacked by this insect are more predis- 

 posed to canker than others. 



One large grower in Kent has treated no less than 40,000 

 young apple stocks for this pest by fumigation with hydro- 

 cyanic acid gas so as to kill both root and stem form. In spite 

 of the trouble of lifting such a large number it has been well re- 

 paid by the disappearance of this blight, whicli is so injurious to 

 old and young stock and so easily spread from the nursery. 

 Where old trees are attacked we now know that the only plan 

 we can follow is to destroy the subterranean race of aphis by 

 injections of bisulphide of carbon into the soil. Experiments 

 during the past season have shown the benefit of this treatment, 

 which was so remunerativ^e to vine growers on the Conti- 

 nent when phylloxera was devastating the vineyards of Europe. 

 For this treatment Vermorel's injector is of the greatest use, and 

 the same implement can be employed for the destruction of wire- 

 worm in other plants, for at present bisulphide of carbon is 

 the only substance known that will kill these larvae in the soil. 

 Woolly aphis was reported during 1906 from Sussex, Kent, 

 Surrey, Hampshire, North and South Devon, Gloucestershire, 

 Herefordshire, W^orcestershire, Huntingdonshire, Essex, Lincoln- 

 shire, and Cheshire. 



The prunes suffered very severely in 1906 from aphis attack 

 in all parts of Britain. Three species were present in such 

 numbers that they must not only have affected the possible 

 crop left by the inclement weather, but must have materially 

 affected the growth of the trees. 



Leaf- c iirling Plmn Aphis. — The leaf-curling plum aphis {Aphis 

 pruni) has occurred all over England, frequent complaints having 

 reached me from all fruit-growing areas. From Whimple to 

 North Yorkshire the same statements have come from growers, 

 namely, that spraying does little good. The reason is that the 

 leaf-curling protects the aphides, and, in consequence, spray- 

 ing is mere waste of time and money. The complete life- 

 history of this aphis is not known. All we do know is that it 



