336 THE MONTHLY BULLETIN. 



An examination was made of the scales on April 15th showing the 

 following result: 



Moist chamber Exposeed sprayed Unsprayed 

 twig twig check 



Number of scales examined 349 331 372 



Percentage alive 30 SO 79 



No trace of the fungus could be found on the sprayed exposed twig, 

 but in the enclosed chamber the fungus was growing in patches on the 

 twigs and scales. 



LABORATORY MOIST CHAMBER TESTS. 



Experiment No, 6, February 11, 1915. 



On the above date six twigs infested with the black scale were cut 

 from mature Eureka lemon trees and taken to the laboratory and cut 

 into suitable lengths. Four of these twigs were then sprayed with the 

 spores and hyphfe of Isaria fungus, placed upright in a dish containing 

 some water, and covered with a bell jar. The remaining two twigs 

 were similarly treated except that they were soaked with water con- 

 taining no fungus. These served as a check to the sprayed twigs. The 

 leaves in this case were not removed and on similar twigs, 83 per cent 

 of the scales were alive. 



On February 18th, or one week later, on the sprayed twigs, patches 

 of the Isaria fungus were growing here and there over both stems and 

 foliage, apparently growing quite rapidly on honey dew in this moist 

 atmosphere. Two or three scales were completely covered but appar- 

 ently the fungus was not yet working on the scales themselves. Febru- 

 ary 24th, one sprayed twig was removed and the scales examined. 

 Sixty-seven scales were examined of which 67 per cent were alive. 

 Eighty-five per cent of the dead scales had fungus in, on, or over them. 

 In one or two cases the fungus was radiating from the sides of the dead 

 scales. One twig from the check moist chamber was also examined and 

 66 per cent of the scales found to be alive. 



On March 11th, the remaining twigs, both sprayed and check twigs, 

 were examined. In the check sample, some of the scales had left the 

 twigs and were in the water or on paper. These were included in the 

 result : 



Sprayed twigs Check twigs 



Number of scales' examined 234 100 



Percentaso nlivr 27 58 



Experiment No. 7, February 24, 1915. 



This experiment was a duplicate of Experiment No. 6, with 77 per 

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

 29th both the sprayed and check twigs were examined with the follow- 

 ing result : 



Sprayed twigs Check twigs 



Number of scales examined 740 852 



Percentage alive 22.7 45.5 



