TREATMENT?“ FOR SAN OSE SCA LEAs 
ORGEHARDS wale 
SPRAYING WITH KEROSENE AND CRUDE PETROLEUM. 
F. A. SIRRINE.. 
SUMMARY. 
The results of these tests, considered in connection with 
others previously reported by this and other stations, appear 
to indicate that spraying with kerosense or crude petroleum is 
safe and effective under the following conditions: 
In using kerosene, only the best grades should be employed, 
as the lower grades are very liable to injure the trees. 
Mechanical mixtures ranging from 15 to 25 per ct. can be 
used on apple and pear while the trees are in full leaf with but 
slight injury to the trees; while mixtures of even less strength 
are liable to cause some injury to stone fruits under the same 
conditions. Such dilute mixtures appear to be of value only 
against young insects unprotected by scales. 
A good grade of kerosene can apparently be applied to large, 
vigorous pear and apple trees while they are completely dor- 
mant and cause little injury; but not to such trees after the 
sap begins to flow. With stone fruits, on the contrary, especi- 
ally with peach, dormant trees suffer from even dilute mix- 
tures, but even pure kerosene may be applied to such trees 
while the buds are swelling but are still unopened. 
Peach and plum can be sprayed quite safely with 25 per ct. 
mechanical mixtures of crude petroleum (4814° to 44° Baumé, 
0.79 sp. gr.) after buds commence to swell. If treated while 
dormant the trees are generally injured, often killed. 
*A reprint of Bulletin No. 213. 
