128 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



deficient. Sulphoccarbonates have therefore their place only in rich 

 vineyards Uke those of Champagne, Burgundy, and Bordeaux. They 

 should be preferred to carbon disulphide, the more so as they are much 

 less dangerous for the vine. As Foex justlv remarks, it i^ a process to 

 use in de luxe, vineyards. There are in France vineyards that have 

 been submitted to this treatment for fifteen years, and still in good 

 condition. In France there are hardly more than 10,000-12,000 

 hectares (25,000-30,000 acres) treated annually by sulphocarbonates, 

 and since the carbon disulphide treatment has been better studied 

 this figure has a tendency to diminish, for the carbon disulphide treat- 

 ment, like the sulphocarbonate, being annual the small doses of sulphide 

 used in such conditions are not prejudicial to the vine and enable it to 

 be kept in a good state of production. Unfortunately, whatever care be 

 taken in applying these substances there will always be a certain 

 number of phylloxera which escape the toxic action. If, theoretically, 

 the sulphocarbonates are capable in small doses of entirely destroying 

 the insects on the roots, it is not so in practice even in much stronger 

 doses ; different causes prevent the result from being so complete. But 

 by the treatment the number of the phylloxera is so reduced as to 

 enable the root hairs formed during the fine weather not to be entirely 

 destroyed, and for the plant to nourish itself on the revival of vegeta- 

 tion. If the evil be not entirely removed it no longer foi'ms an obstacle 

 to the vine maintaining its vigour. The important point is to diminish 

 the parasites, so that the vine may live with them without the crop 

 suffering. The use of water as the vehicle of the sulphocarbonate 

 being the great obstacle to the propagation of this marvellous insecticide, 

 it has been tried whether mixtures with slaked lime would not likewise 

 bring about a uniform distribution of the sulphocarbonates in the soil. 

 It was Dumas who advised Mouillefert to try these mixtures, hoping 

 that the lime, before its transformation into carbonate, would absorb 

 the carbonic acid of the air and prevent the sulphocarbonate decom- 

 posing rapidly. In this way a powder would be got easily spread in 

 the soil at the foot of the stocks, which would preserve the alkaline 

 carbonate intact whilst waiting for rain to carry it into the neiiibbour- 

 hood of the infected roots. Mouillefert, therefore, mixed 500 cubic 

 centimetres of sulphocarbonate of potash of 37° B. with 1-2 kilo- 

 grammes of lime in powder and spread this mixture in winter at the 

 foot of five stocks, previously stripped to the big roots on a radius of 

 35-45 centimetres ; the earth was then put back into the holes. A 

 fortnight later after a series of heavy rains the roots were examined ; 

 on all the top roots the insects were dead, but on the roots more than 

 40 centimetres (say 6 inches) the insects were not found dead until 

 two months afterwards. Success would have been complete if it had 

 not been that on the roots beyond the stripped radius the phylloxera 

 were still living. According to the predictions of Dumas, the use 

 of sulphocarbonate in these conditions may suffice, provided the 

 mixture be spread all over the vineyard. To attain this object the 

 proportion of lime must be increased greatly, and a mixture of 500 

 kilogrammes of sulphocarbonate with 5000 kilogrammes of slaked 

 lime a]Dplied per hectare of vineyard (say 440 lb. and 4400 lb., 2 metric 



