170 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



those alive that were exposed to the gas 60 minutes. This very poor 

 stand, due to excessive wet weather in the experiment as well as 

 throughout the field, caused the abandonment of further observations. 

 It may be said that it so happened that in each test the 60-minute ex- 

 posure gave a larger per cent of live buds than the 30-minute exposure 

 at this examination. 



3. On September 7, 1906, 270 peach buds cut from orchard trees 

 were fumigated with 0.285, 0.35 and 0.40 grams of cyanide per cubic 

 foot, with an exposure of 80 minutes. An equal number of Elberta 

 and Heaths Freestone varieties M^ere employed in each test and all 

 buds were known to be infested with San Jose scale. 



An examination of the buds on October 13, 1906, showed 100 per cent 

 of the buds in all tests to be alive, while at the final examination, Au- 

 gust 30, 1907, an average of 34.2 per cent of the buds were alive. At 

 this examination no live scale could be found on any of the buds, 

 showing that all the strengths killed the scale. 



4. On August 27, 1907, 624 peach buds. Late Crawford variety, were 

 fumigated with 0.18, 0.20 and 0.30 grams of cyanide per cubic foot, 

 exposed 45 minutes. All buds in the test were known to be infested 

 with the San Jose scale. At the final examination, September 10, 1908, 

 an average of 52.7 per cent of the buds in the test and 52.2 per cent of 

 those in the check, which were not fumigated, w^ere alive. No live scale 

 could be found on any of the buds fumigated. 



5. On December 4,. 1906, 500 nursery trees were fumigated in ten 

 different lots of 20 peach and 30 apple with 0.15, 0.20, 0.30, 0.40 and 

 0.50 grams cyanide per cubic foot, for 30 and 60 minutes respectively. 

 All trees were badly infested with the San Jose scale. 



At the final examination of the trees, September, 1907, all were liv- 

 ing' and vigorous. Living scale was found on some of the trees in each 

 test below those fumigated with 0.30 grams per cubic foot, with an 

 exposure of 60 minutes. 



A second experiment, consisting of 8 tests with 10 apple trees in 

 each, badly infested with scale, fumigated wdth 0.15, 0.20, 0.28 and 

 0.50 grams cyanide per cubic foot and exposed 30 and 60 minutes re- 

 spectively, was conducted November 2, 1906. This lot of trees were de- 

 layed en route to College Park and accordingly were not in good con- 

 dition for planting upon arrival. For this reason no accurate con- 

 clusions can be drawn, but at the final examination an average of six 

 trees in each test were living and no more trees were dead in the test 

 with the highest strength of gas and the 60-minute exposure than in the 

 test of the weakest gas, with shortest duration of exposure. Further 



