72 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



phylloxeric invasion for several years, it has never, on the other hand, 

 prevented subsequent invasions, so that this very costly treatment 

 has been abandoned. 



Cropping Treatment. — Instead of destroying the vine by massive 

 doses of 2^ tons to 3 tons of carbon disulphide per hectare (1 ton to 

 24 cwt. per acre), its sanitary condition is to-day improved by an 

 annual disinfection of 200-250 kilogrammes per hectare (176-220 lb. 

 per acre), accompanied by more abundant manuring ; instead of losing 

 the precious time required to form a vineyard, the attacked vines are 

 maintained in a good state of production. There are some that stand 

 this treatment for thirty years, and are in perfect health. In Mouille- 

 fert's opinion, neither the cropping treatment, even in big doses, nor the 

 submersion, nor other methods, give anything but incomplete results. 

 Some insects always escape destruction because the distribution of a 

 gas or a liquid through a layer of soil of unequal composition can 

 never be perfect. If this treatment be not annual, it will be of no use, 

 but annual treatment accomplishes perfectly the end in view, for it 

 then annually frees the vine from the greater number of its parasites, 

 and enables it each year to regenerate its atrophied roots, and to live, 

 therefore, with its parasite without suffering too much from it. Every 

 rational observer must therefore acknowledge that if this process be 

 not perfect, and that plants grafted on vines immune to this insect have 

 been the safeguard of the vine-grower, carbon disulphide has rendered 

 great service by preserving the greater part of the French vines in a 

 good state of production. The pure sulphide, or its solution, in water 

 may be used. 



Use of Pure Carbon Disulphide. — So that the treatment with 

 carbon disulphide may give the desired result, it must be used accord- 

 ing to the rules established by numerous experiments, and formulated 

 by our leai'ned professors. The accidents and mishaps that befel 

 certain vine-growers were due to working during bad periods, and on 

 unfit soil. Dr. Colas formulated in 1877 the rules for the use of 

 carbon disulphide : (1) Treat the phylloxera as soon as it appears. 

 (2) Treat the whole of the vines, and not the spots only. (3) Apply 

 carbon disulphide in doses of 18-20 grammes per square metre, say § of 

 an oz. (wt.) per square yard. (4) Make injections between the stocks 

 so as to place each of them between four holes, avoiding touching the 

 roots with the pal. (5) Sink the pal only 15-20 centimetres (6-8 inches) 

 deep. (6) Take care to plug the holes immediately after the operation. 

 (7) Always take care to let heavy soils, which retain water a long time, 

 drain after heavy rains and thaws. (8) Avoid treatment at the two 

 seasons of the year when the sap begins to move. (9) Cultivate and 

 manure the vines treated in a suitable manner. (10) Avoid treatment 

 when frost is feared. 



These rules have not been appreciably altered up to now. To 

 create around the vine an atmosphere uniformly charged with vapours 

 of carbon disulphide, uniform doses must be made to penetrate into the 

 soil at equal distances. An arrangement of holes as uniform as possible 

 must be chosen, and the treatment applied uniformly over all the ex- 

 tent of ground to be disinfected. Not less than 20,000 holes per hectare 



