REPORT OF THE STATE ENTOMOLOGIST I9OO 973 



following experiments is such as may be obtained of the Standard oil 

 CO., and a sample of it sent to Dr Smith the following December tested 

 but 370 on the Beaume oil scale. Crude petroleum purchased at this 

 time of the same firm and presumably from the same source tested 41.50. 

 The agent asserts this oil to be of fairly constant composition, but that 

 appears to be an open question. It is very probable that we must have a 

 product of more constant composition before the most satisfactory results 

 can be obtained in its use as an insecticide. 



Experiments with 20 and 25 % mechanical emulsions and ^vith the 

 undiluted product were tried and the results are detailed below. 



20 % 7Jiecha?iical emulsion. This was given a thorough test on 23 

 trees. Their condition at the beginning of the experiment, Ap. 11, was 

 as follows. Tree 4, a wild cherry 4 feet high, was infested with but i^w 

 scales. Tree 5, a Crawford peach 12 feet high, was moderately in- 

 fested with the scale. Tree 6, a Crataegus 10 feet high, was infested 

 with but few scales. Tree 7, a botan plum about 9 feet high, was 

 moderately infested with the scale. Trees 15 and 16, seckel pear, were 

 badly infested, the former 14 and the latter 8 feet high. Trees 17 and 

 18, an early, unnamed pear 18 feet high, were infested with but few scales. 

 Tree 19, a Bartlett pear 15 feet high, was badly infested. Tree 22, a 

 Howell pear 10 feet high, was very badly infested. Tree 25, a beurre bose 

 pear 8 feet high, was very badly infested. Trees 26 and 27, Kieffer pear 

 10 feet high, were rather badly infested. Tree 28, a seckel pear 10 

 feet high, w^as very badly infested. Tree 41, a Crawford peach 11 

 feet high, was badly infested with the scale. Trees 43-45 and 47, old 

 Mixon peach between 11 and 12 feet high, were all badly infested, tree 

 43 being graded as very badly infested. Tree 46, a champion quince 

 6 feet high, was infested with but few scales. Tree 48, a crab-apple 8 

 feet high, was infested with but few scales. Tree 49, an abundance plum 

 10 feet high, was badly infested with the scale. 



The spraying with crude oil was under the same conditions as when 

 kerosene was used. It was bright, sunny, airy weather which was 

 followed the next day by heavy rains, and this by more within a few 

 days. The spraying was as thorough as possible without going to the 

 trouble of waiting for the wind in opposite directions, something hardly 

 practicable when the orchard was two miles distant. The treatment was 

 probably more thorough than that with kerosene, because the crude oil 

 is easily seen, and a small area skipped is therefore very apparent, 

 which is not true of kerosene on account of the rapid evaporation of 

 the latter. 



