976 NEW YORK STATE MUSEUM 



Experiments with undiluted oil. Four trees were treated with crude 

 oil. The number was limited because it was considered rather 

 hazardous to use this material. The condition of the trees at the be- 

 ginning of the experiment was as follows. Tree 93, a Lombard plum 

 14 feet high, and tree 94, a botan plum 10 feet high, were both moder- 

 ately infested with the scale. Tree 101, a seckel pear 9 feet high 

 and tree 114, a seckel pear 12 feet high, were both very badly infested 

 with the scale. The spraying was done under conditions identical 

 with the preceding. Trees 93 and 94 were sprayed very thoroughly 

 and possibly may have received more oil than the others. 



Ap. 19. The petroleum is very apparent on trees 93, 94, 101 and 

 114, which were well covered. The buds are starting on tree 101. 

 The condition of tree 114 at this time is shown on pi. 6. 



May 11. Tree 93 is retarded considerably and has relatively few leaves 

 and blossoms ( pi. 7). Tree 94 is killed back to the limbs about 

 one third of an inch in diameter. The buds are just starting. Tree 

 101 is very backward, the leaves and blossoms are just starting. 

 Tree 114 has only a few leaves appearing at the tips of the twigs. For 

 a photograph of tree 101, taken May 12, see pi. 9. 



May 14. The leaves of tree 93 are much thinner and more backward 

 than on adjacent trees. There are few blossoms. Only a few buds are 

 starting on tree 94. All the smaller limbs are killed back. Only a few 

 leaves and blossoms are starting at the tips of the branches of tree 101. 

 A few leaves are pardy out at the tips of the branches and but few blos- 

 soms occur on tree 114. 



May 28. The leaves are out considerably on tree 93, but the foliage 

 is still much thinner than on other trees. The oil is very apparent on the 

 trunk and limbs. Tree 94 has developed one weak leaf. Some twigs 

 are still green beneath the outer bark. There are a very few pale, under- 

 sized leaves on the tips of the branches and a few leafless limbs on tree 

 101. 



June 20. The leaves are much thinner on tree 93 than on others adja- 

 cent. The lateral buds have suffered most. The petroleum is very evident 

 on the bark. Tree 94 is dead. Tree 101 has only a few bunches of pale 

 green leaves on four limbs and on the suckers. Many of the lateral 

 buds on tree 114 are killed. The shoots are growing well but the 

 foliage is thin. Adventitious buds are developing. 



July 2. Trees 93, 101, 114 have a few living young scales. The 

 condition of tree 93 is represented on pi. 8, which should be compared 

 with the other figure, showing the condition of a companion tree, 



