HOT SPRAYING AGAINST COCHYLIS. 



39 



act rapidly. He should with the drawn-out spout of the coffee-pot 

 pour the hot water on the stock, rising in a spiral from the hottom, so 

 that the water at the required temperature penetrates into all the 

 interstices of the bark. The operation must be performed from 

 below upwards, for if scalding was begun from the top of the stock 

 the excess of water, perforce cooled, would flow over the lower parts 

 and fill the interstices ; the boiling water poured afterwards would 

 have no mortal effect on the insects on the bottom of the stock, 

 because they would not receive it directly. This precaution is parti- 

 cularly necessary in treating old vines, because these are generally the 

 refuge preferred by grubs owing to the rugosity of the stock. Two 

 workmen suffice to carry out the scalding ; one feeds the fire and fills 

 the boiler as the boiling water is drawn off, the other runs the hot 

 water into the coffee-pots and pours their contents on the stocks. 

 Working thus, 1500-2000 stocks can be treated per day. The boiler 



Fig. 2. — Coffee-Pot for Sciildiug Vines 

 with Hot Water. 



Fig. 1.— Portable Boiler. 



consumes about 200 kilogrammes (4 cwt.) of coal per day. To diminish 

 the labour, large boilers are also used, with taps to which india-rubber 

 tubing is attached ending in a nozzle, with intermittent jet. This 

 nozzle which projects the water on the stock has the advantage of 

 penetrating deeply into the cracks of the bark. This process, though 

 preferable to others, is only used in large vineyards. Scalding should 

 be done after the vintage when the grubs have taken refuge in the 

 bark, and before they have assumed the chrysalis form, for the latter 

 is not so sensitive as the grub. It is carried out as soon as pruning 

 is finished and preferably in calm, fine weather. To combat the 

 Cochylis it is necessary to operate in October or November, whilst the 

 grub has not yet finished its cocoon ; against the Pyralis, which re- 

 mains all winter as a grub, proceedings can be taken all winter up 

 to May before escape from the cocoon. In districts where props are 

 used these are boiled by placing them in cases, into which steam is 

 injected for eight to ten minutes, or by steeping them in boiling water 



