276 Report oF THE DEPARTMENT OF ENTOMOLOGY OF THE 
Taste VIII.— Errect or CrupE PETROLEUM ON SAN JOSE SCALE. 
SERIES II. TWENTY-FIVE PER CT. PETROLEUM 3 SPECIFIC GRAVITY 0.79. 
Number of treatments. eee es ae Condition of scales. 
(a) One, December.} Apple....| Apr. 10 | A few living specimens found on 
infested trees. 
Aug. 2 | Jonathans show living scales on 

fruit. 
Peach....| Mar. 18 | No living scales on twigs sent for 
examination. 
Plum....| Mar. 7 | Living scales on twigs sent for 
examination. 
June 18 | Living scales found in exposed 
places. Trees moderately in- 
fested at time of treatment. 
(b) Two, Dec., Apr.) Apple....| June 19 | Living scales found on Jonathan. 
Nov. Living scale found on fruit of 
Jonathan. 
| Peach.... (Trees killed.) 
Plum ....}; June 18 _ Living scales found on one tree 
| slightly infested at time of 
treatment. 
CC) APCS ODI 55's b Apple... «|. Noy, A few living scales found on fruit 
' of Baldwins and Jonathans. 
Peach....| June 18 | Living séales found on body of 
| trees in exposed places.' 
Plum ....}| June 18 | Living scales found on trees in 
exposed places. 
Aug. 26 | Trees still show a few living scales. 




DIGEST OF RESULTS FROM USE OF CRUDE PETROLEUM. 
Ejfect on trees.—The tests made in the spring of 1900 show, 
first, that pure crude petroleum and even a 50 per ct. mechanical 
mixture of a grade known as “Gas oil” or “ Reduced oil” 
(specific gravity 0.837) cannot be safely used on either apple, 
peach or pear. Second, that crude petroleum, specific gravity 
0.795 or heavier, cannot be used even in a mechanical mixture 
of 15 per ct. on pear after the buds are swollen, without some 
injury to the set of fruit, and where used in a mechanical mix- 
ture of 50 and 60 per ct., all the fruit buds reached were killed, 
IMany of the living specimens found on peach and plum were in exposed places on body and 
larger branches. In most cases they were on the underside of a branch where it joined the body, 
or in spots’which showedslight’or"no’traces of crude’petroleum.f>, in one instance where the 1 
per cent mechanical’mixture was'used, they"were found’on the smooth’ bark of plum, where'they 
should have been reached, and’everything indicated’that they had been reached withfthe spray. 
1n the case of apples the living specimens"were‘generally found under buds.®: Their occurrence 
on fruit of apple, also on plum, indicstes that they were not reached at tips of branches, under 
buds and bud clusters. 
