484 



Insect Pests. 



D. longispinusalso occurs in the open in South Europe, Africa, Ceylon 



and the West Indies. 



TREATMENT. 

 In vineries the best treatment is fumigation with hydrocyanic 



acid gas. For this purpose the quantities used vary. It is necessary 



to have a separate 

 machine for fumigat- 

 ing for every 10,000 

 cubic feet of space in 

 a vinery. 



A fan should be 

 fixed over the fumes 

 so as to spread them 

 evenly over the house, 

 and the time the fumes 

 are allowed to remain 

 should be about forty- 

 five minutes. Xo other 

 treatment is quite 

 satisfactory, and even 

 the gas treatment 

 wants repeating twice 

 at an interval of about 

 two weeks (vide Fumi- 

 gation). 

 The quantities experimented with by Cousins (1), who first brought 



this treatment out in this country, are quoted here in c.:dcnso : 



" VINERY A. Capacity, 3,430 cubic feet. 



Early variety. Treated when vines in full bloom. 

 Cyanide, 18 oz. ; acid, 27 fluid oz. ; 1 quart water. 

 Temperature, 60 F. Time, half an hour. After sunset. 



"Result.- Mealybug destroyed, foliage unhurt, but three-quartern 

 of the bloom injured. A few mealy bugs appeared at the close of 

 the season after the grapes had been gathered. A second fumigation 

 was therefore decided upon, and the results so far have been com- 

 pletely satisfactory. 



" YIXERY B. Capacity, 3,825 cubic feet. 



Late variety. Treated before vines bloomed. 



Cyanide, 27 oz. ; acid, 40 oz. ; water, 60 oz. 



Time, 3 hours. After sunset. Temperature, 60 F. 



KIG. 314. YOl'XC 



[J. G. Blakeij. 



JUST HATCHED. (X 3.) 



