MORE ABOUT THE GRAPE-VINE PEST, 165 



in winter is required, and even where the water is allowed to remain 

 during the whole of this season the vineyard does not suffer. 3. A 

 vineyard should never be inundated for a longer period than two days 

 in summer, or during growth ; and though these brief inundations at 

 that season affect only the few lice near the surface, and are by no 

 means essential, they are nevertheless important auxiliaries to the 

 more thorough fall or winter submersion, as they destroy the few lice 

 which are always invading a vineyard in infested districts. These 

 summer inundations will be necessary only after the winged insects 

 begin to appear ; and three or four, each lasting less than two days, 

 made between the middle of July and the fall of the leaf, will effect 

 the end desired. 4. An embankment should be made around the vine- 

 yard, in order that the water may evaporate and permeate the earth, 

 but not run off and carry away any nutritive properties of the soil. 



The varied success which has attended the different attempts to 

 rout the enemy by inundation, is owing to the lack of thoroughness in 

 many of them. The ground must be thoroughly soaked for a suffi- 

 cient length of time. Temporary irrigation does not accomplish the 

 end, for the reason that it does not reach all the lice, and does not 

 break up the numerous air-bubbles which form in the soil, and prevent 

 the drowning of many of the insects. 



On our best hilly vine-land thorough submersion is impracticable, 

 but on our bottom-lands some of the grapes, which fail now, may be 

 made to succeed by its meang. 



Of 140 different applications made by an intelligent and competent 

 commission in the department of Herault, France, most of the pure 

 insecticides proved valueless. Many of them, such as carbolic acid, 

 oil of cade, arsenious acid, sulphide of calcium, sulphide of mercury, 

 arseniate of potash, etc., etc., will effectually kill the insect when 

 brought in direct contact with it; but, in field-practice, they can 

 either not be brought in this direct contact, or else cannot be used 

 strong enougli to kill all the lice without injuriously affecting the 

 vine. 



Carbolic acid added to water, at the rate of about one per cent., 

 applied by pouring into deep holes, made by a crow-bar or auger, has 

 given satisfactory results ; and a thprough application of soot has also 

 been strongly advocated by those who have tried it. In the experi- 

 ments that I have been able to make, in a small way, a thorough mix- 

 ing with the soil of a cheap carbolic powder, prepared by G. Mallinck- 

 rodt & Co., of St. Louis, has given good results. 



The latest insecticide that has attracted attention and given great 

 hopes in France is the bisulphide of carbon. It seems to have been 

 used as early as 1869 by Baron Thenard, but was brought prominently 

 before the public last autumn by Messrs. Monestier, Lautand, and 

 D'Ortoman, who first proposed to introduce it at a great depth in the 

 soil, so as to utilize its vapor. A vapor will naturally have the advan- 



