79^ CONNECTICUT EXPERIMENT STATION REPORT, I9O7-I908. 



imum may result in killing or injuring- the trees. It should be 

 understood that these tests apply only to apple and peach, and 

 chiefly the former, and against the San Jose scale and no other 

 insect. 



Carbon Tetrachloride. 



This liquid was used in exactly the same way as the carbon 

 disulphide, the same metal cases and heated frying pans being 

 used. The quantities used, period of fumigation and results, are 

 given in Table I. The results do not correspond very closely 

 with those obtained in last year's tests, in that some scales survived 

 in each case, where last year all were killed. Last year it seemed 

 that carbon tetrachloride was a promising material, and its good 

 qualities ware mentioned in the Report. Though further trials 

 may still prove it to be of some value as an insecticide, in the light 

 of the 1908 tests it does not appear as promising as it did a year 

 ago. Nevertheless, the figures are given here for what they are 

 worth without further comment than to state that carbon disul- 

 phide, in spite of the inflammability and bad odor, seems to be 

 more desirable for fumigating nursery trees to kill the San 

 Jose scale than carbon tetrachloride. 



Acetylene. 



This was generated in a granite iron dish from crushed calcium 

 carbide, the largest pieces being about one inch in diameter. 

 Instead of the metal case a long wooden box was used. In Test 

 No. 21 this box was used right side up with a tight cover, the 

 carbide weighed out and placed in the dish, and the water poured 

 in by means of a funnel through a hole in the cover. In the 

 other tests the box was inverted over the trees on the ground, and 

 the earth banked up around the edges of the box to make it 

 tight. A small box was sunk in the ground under the middle 

 of the long box, and this, projecting outward from one side, 

 served as a place to introduce the materials. The opening in the 

 small box was then quickly covered and banked with earth. 



The data regarding the tests with acetylene will be found in 

 Table I, but do not show this gas to be very effective in destroy- 

 ing the scale when used in the quantities and for the fumigating 

 periods used in this experiment. 



