94 ENTOMOLOGICAL SOCIETY OF ONTARIO. 



the treated trees overtopped the others both in abundance of foliage and amount of rew 

 growth, and at the present writing, July 20, there seems to have been no id jury what- 

 ever as a result of the treatment. 



The large peach tree sprayed showed no ill e fleets, and all of the scales on the tree 

 were killed except where they had been protected in a few instances by masses of leaves 

 webbed about the limbs. At least 99 per cent, of the scales were killed. On the 

 euonymous a similar result was shown, at least 99 per cent, of scales having also been 

 killed by the oil. 



These results are so greatly in contrast with those previously attained in the e> neri- 

 ments conducted in practically the same way that it seems difficult to account for Llf-m. 

 That spraying with pure oil will often kill trees can not be doubted, even when applied 

 in the dormant condition in winter, as demonstrated by experiments on a number of 

 apple and peach trees two or three seasons ago. It is possible that with these earlier 

 experiments the same care was not employed to prevent the collection of oil about the 

 trunks of the trees and the trees were not mounded up, but the work was as carefully 

 done as would ordinarily be the case in actual practice, and probably much more so. It is 

 possible, therefore, that tie death of the trees in some instances was due to the collec- 

 tion of the oil in the cavity formed about the trunk by the swaying of the tret 8 in the 

 wind, which, as will be shown later, has had disastrous results in California with the 

 emulsion even. Others have reported the use of oil on trees without injurious effects 

 in some instances and in others with injurious effects, so that pure oil as an insecticide 

 is one to be used with caution and with full appreciation of the fact that the death of the 

 plant may result. 



Use of Kerosene Emulsion in California. 



This insecticide is used to a very considerable extent in California, much more so in 

 recent years than formerly. It is the principal insecticide used in the district about San 

 Diego, and is also used extensively at Santa Barbara and to a less extent elsewhere in 

 the State. The necessity for the use of very large quantities of insecticides in California 

 has led to the establishment by private parties in several instances of steam or gasoline 

 plants for the wholesale production of this insecticide. Probably the first extensive manu- 

 facturing plant of this sort was set up by Mr. W. E. Gunnis, county horticultural commis- 

 sioner, of San Diego, who manufactures the emulsion by the aid of a small engine, doing all 

 the work of heating, churning, etc., by this means. With coal oil at 11 cents per gallon, 

 he is able to produce the emulsion at a charge of 13 cents per gallon in the undiluted 

 state, which makes the wash as applied to the trees, diuted 7 time?, cost a little over 1 J 

 cents per gallon. In his district, Mr. Gunnis claims that the loss from scale insects has 

 been reduced from 79 per cent, to 7 per cent., chiefly by the use of this wash. 



At Santa Barbara the superintendent of the Las Fuentos ranch, Mr. Frank Kables, 

 has set up a very large plant for the manufacture of kerosene emulsion for the use of this 

 ranch alone. The plant is similar to that devised by Mr. Gunnis, and the capacity is 

 such that the emulsion can be made in quantities of 150 gallons at a time and very 

 rapidly. He uses a formula slightly different from the Hubbard. The proportions are 

 35 gallons of whale-oil soap, 100 gallons of kerosene oil, and 50 gallons of water. This 

 is diluted for application to trees with seven parts water, costing in the diluted state 1^ 

 cents per gallon. 



Kerosene emulsion has probably been given its most extensive trial on the Pacific 

 Coast at the Las Fuentos ranch. Two years since Mr. Gunnings sent his excellent 

 spraying apparatus to Santa Barbara, together with some 8,000 or 10,000 gallons of 

 emulsion, and thoroughly sprayed the lemon plantings, comprising upward of 25,000 

 trees. 



In some of the earlier work many trees were killed, owing probably to the accumu- 

 lation of oil in the bottom of the reservoir or tank, so that the last three or four trees 

 with each filling received an unusually heavy dose, which, running down the trunk, col- 



