CARBON DISFLPHIDE. 71 



of " gallicole," is done by methods described further on. However, 

 it may be carried out l)y means of carbon disulphide on grafts and 

 buds from a contaminated region, because a sojourn of an hour in an 

 atmosphere saturated with the vapour of this insecticide is sufficient 

 to kill the phylloxera and its eggs. Buds and plants may be so dis- 

 infected. 



Underground Disinfection. — This method of disinfection is the 

 most important. It is, in fact, because it withers the roots of the 

 vine that the phylloxera kills this plant and destroys entire vineyards. 

 Amongst the numerous insecticides, proposed for the destruction of 

 the phylloxera, carbon disulphide, and its derivatives, the sulpho- 

 carbonates, have alone given good results. According to the district, 

 and also as circumstances may require, two distinct treatments may 

 be applied : — 



1. The extermination process, destroying all the insects of the vine 

 and the plant itself. 



2. The cropping process, only destroying a portion of the insects, 

 and not injuring the vine, so that the latter, in spite of its parasites, 

 may produce sufficient crops. 



Extermination Treatment. — In districts far from invaded centres, 

 where an invasion of the phylloxera is in its initial stage and shows 

 itself in certain isolated spots, which threaten a whole vineyard, there 

 must be no hesitation at the right moment to adopt the extermination 

 treatment, which is capable of radically arresting the propagation of 

 the insect, but it is necessary to sacrifice, at the same time, the 

 attacked vines. This process, which is less and less used, since by 

 the cropping treatment the plant may be maintained in a passable 

 state of resistance, was in use, and even obligatory, in the borders of 

 France, Switzerland, and Alsace-Lorraine, the vine}ards of which, 

 constantly threatened by destruction, were only preserved by these 

 drastic measures. The extermination treatment is as follows : As 

 soon as the phylloxera makes its appearance in a vineyard, the vine 

 stems are cut down level with the ground, over the whole surface 

 infected ; these stems are burned on the spot. Before pulling up the 

 stocks, holes 60 centimetres (24 inches) deep, 50 centimetres (20 

 inches) apart, in all directions, are made in the soil, and 50-100 cubic 

 centimetres (l|-3-| fi. oz.) of carbon disulphide poured into each 

 hole, which is plugged. If the soil be dry it is slightly watered, so that 

 .there forms on the surface a slight crust, which prevents the too rapid 

 evaporation of the insecticide into the air. Three years after this dis- 

 infection all the stocks with their roots are pulled up and burned on 

 the spot, after drenching them with tar. Fifteen days afterwards two 

 new applications are made with weaker doses ; 50 cubic centimetres 

 per hole then suffice. In Alsace-Lorraine, where this treatment was 

 prescribed, it was forbidden to replant the vine for ten years. Since 

 the researches of Oberlin and Dufour have cleared the minds of the 

 authorities, the vine can be replanted the spring following the treat- 

 ment. These vines are, moreover, of extraordinary vigour, and yield 

 from the fourth year a better crop than that obtained in untreated 

 vineyards. If the extinction treatment was capable of retarding the 



