968 . NEW YORK STATE MUSEUM 



shown on pi. 3. Each tree received a number, which was retained 

 throughout the experiment. Notes on the the condition of the individual 

 tree precede the experimental records given under the various insecti- 

 cides. All the spraying was done with a Gould kerowater sprayer, and 

 the mechanical emulsions were those delivered by this excellent appa- 

 ratus through a pair of cyclone nozzles. 



Experiments with kerosene against San Jose scale. This 

 insecticide was applied in three strengths, 20 and 25% mechanical 

 emulsions and undiluted. The treatment was given Ap. 11, at which 

 time the buds had not started. 



20% mechanical emulsion. 17 trees were treated witii this kerosene 

 mixture. Their condition at the time of spraying, Ap. 11, was as fol- 

 lows. Trees i and 2 were large apple trees, slightly infested with the 

 scale. The spra)ing apparatus was not adapted to treating large trees, 

 and these two were included sinij)ly because they were m the field, and 

 their treatment was more to keep the pest in check than for experimental 

 purposes. Tree 3, a light oxheart cherry 12 feet high, was moderately 

 infested with the scale. It was a vigorous tree, which had not suffered 

 to any appreciable extent from the pest. Tree 8, a badly infested Lom- 

 bard plum, was 14 feet high. Its vigor had not been seriously affected 

 by the scale. Tree 9, a badly infested botan plum 19 feet high, was in 

 about the same condition as tree 8. Tree 10, a moderately infested 

 beurre bosc pear, was 12 feet high. Trees 11-14 ^re seckel pears; the 

 first was about 9 feet high and moderately infested, the others were 

 about 15 feet high and badly infested with the scale. The vitality of 

 none of them had been seriously impaired. Trees 38-39, very badly 

 infested globe peachtrees, were 8 feet high. Tree 40, a badly infested 

 Crawford peachtree, was 10 feet high. Tree 50, a badly infested Idaho 

 pear, was 10 feet high. Tree 51, a moderately infested botan plum, was 

 10 feet high. Trees 52 and 53 were the same as 51, except that they 

 were badly infested and were 13 feet high. The spraying was as thor- 

 ough as could be given without having large amounts of the oil and 

 water run down the trunk. The work was done on a sunny, airy day. 

 The next day it rained considerably and this was followed by more 

 rain within a few days. 



Ap. 19. Tree 3, the uuus are bursting, and little or no kerosene is 

 evident, though the bark is somewhat greasy. Trees 8-14. The kerosene 

 it scarcely evident, and the bark is somewhat greasy. Trees 38-40. 

 The kerosene is hardly evident. The buds are starting, and there are 

 living agar case-bearer larvae on tree 2^^^ and eggs of the appletree tent- 



