334 THE MONTHLY BULLETIN, 



On April 15th the final examination of these twigs was made with 

 the following result: 



Sprayed twigs Check twigs 



Number of scales examined 577 372 



Percentage alive 70 79 



No trace of fungus could be found at this time although the climatic 

 conditions during February, so far as moisture conditions were con- 

 cerned, were as favorable for its development as could be expected in 

 that section. 



Experiment No. 2, February 11, 1915. 



On this date the procedure described under Experiment No. 1 was 

 repeated. Several infested twigs were sprayed with the spores and 

 liyphae of Isaria. To determine whether or not the spores were viable, 

 some were placed in drop slides and on the following morning, or 

 sixteen hours later, were found to have germinated. Eighty-five per 

 cent of the scales were alive at the time of beginning the experiment. 

 On March 29th one sprayed twig was cut from each tree and the scales 

 examined with the following result: 



Sprayed twigs Checlc twigs 



Number of scales examined 1,045 301 



Percpntai;o alive 83 86 



April 15th the remaining twigs sprayed on February 11th were cut 

 and .scales examined with the following result : 



Sprayed twigs Cheek twigs 



Niunbor of .scales examined 404 372 



Percentage alive 76 79 



No trace of the fungus could he found on the scales or twigs. 



Experiment No. 3, February 27, 1915. 



On this date the same program as above was repeated and the spores 

 and liyphffi of Isaria were sprayed on four twigs very heavily infested 

 with black scale. Seventy-five per cent of the scales were alive at the 

 l)eginning of the experiment. 



On April 15th examination was made with the following result: 



Sprayed twigs Check twigs 



Number of scales examined 280 .372 



Pi'iT-entage alive 87 79 



No Isaria fungus could be detected on scales or twigs. 



FIELD MOIST CHAMBER TESTS. 



Experiment No. 4, March 8, 1915. 

 One twig on each of two trees infested with black scale was sprayed 

 with the spores and hypha of Isaria and then enclosed in a moist cham- 

 ber by means of a sheet of celluloid 17 inches by 10 inches. This was 

 placed around the twig, tied, and the edges glued together. The open 

 ends of the cylinder were plugged with cotton. One twig on each tree 

 was also sprayed with the fungus but not enclosed in the moist chamber. 

 An examination of 745 scales on sample twigs at the time of starting 

 the experiment indicated that practically 69 per cent were alive. 



