484 



Insect Pests. 



D. lo nr/ iqnn us nl&o occurs in the open in Soutli Europe, Africa, Ceylon 

 and the West Indies. 



TeEATxMENT. 



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. No 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.vfemo : — 



" 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-quartera 

 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. 



" Vinery 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. 



[./. G. Blakfij. 



-YOUNG MEALY BUGS JUST HATCHED. (X 3.) 



