2978 Report oF THE DEPARTMENT OF ENTOMOLOGY OF THE 
Results obtained by Felt® show that pears treated with 20 and 
25 per ct. mechanical mixtures of crude petroleum applied in 
April were injured. 
Sanderson? reports no injury to pears sprayed March 21 with 
a 25 per ct. mechanical mixture of crude petroleum. 
From observations made in orchards in the Hudson Valley, 
Slingerland” concludes that there is less danger of injury to 
apple trees, from a 25 per ct. mechanical mixture of crude 
petroleum, if sprayed in April instead of earlier in the winter. 
Webster! reports injury to three-year-old apple trees, by an 
application of pure crude petroleum, sp. gr. 0.83, applied in 
March. His illustrations show that one tree had all leaf and 
fruit buds, reached by the crude petroleum, killed; after which 
the trees developed latent buds. 
Johnson” says: “Apple and pear can be treated with crude 
oil] pure or in a mechanical mixture, any time during winter. 
The same material can be used on plum and peach in a 20 to 25 
per ct. mixture, but the application should not be made before 
March or April.” 
Smith has shown that pure crude petroleum can be applied to 
peach in early spring without injury. It should be explained 
that his results were obtained on small trees that could either 
be painted by hand or sprayed with a small hand atomizer, 
hence do not furnish a fair basis for comparison with orchard 
work in general. 
Many more instances might be added, showing how variable 
the results obtained can be. These have been obtained under 
just as variable conditions as those from the use of kerosene, 
hence are just as difficult to compare. 
In general, all the results obtained through Experiment Sta- 
tion tests, together with those obtained by orchardists, show 
that peach and plum can be quite safely sprayed with 25 per et. 
mechanical mixtures of crude petroleum having a specific grav- 
816th Rept. State Ent. on Injurious and other Insects, 1901. 
912th Ann. Rept. Del. Coll. Agr. Exp. Sta., 1900. 
10Rural New-Yorker, Nov. 3, 1900. 
Ohio Hort. Rept., 1900. 
12Amer. Agrl., Dec. 29, 1900. 
3N. J. Agr. Coll. Exp. Sta. Rept. for 1889 and 196@. 
