570 ANNUAL KJSPOKT OF THE Off. Doc. 



in kind or strength, according to the plants to which they are 

 to be applied or according to the season for application. Where 

 the pest is abundant, summer remedies should be applied in order 

 to check it so that it will not be able to injure the trees seriously 

 before the dormant season. The summer remedies may be: 



(1) Whale oil soap, one pound in six gallons of water, used as a 

 spray. 



(2) Kerosene emulsion. 



(3) Kerosene mixture. 



These should not be stronger than 20 per cent, kerosene for 

 apple trees and not stronger than 12 per cent, kerosene for peach 

 trees. They will not kill the adult or scale insect, but they will 

 kill the young pest while it is crawling around and in its tender con- 

 dition. They may be in this stage from one to two days, according 

 to temperature, but not longer. Of course, during that time they 

 are not covered by a waxy scale as is the adult, and they are killed 

 by such simple contact applications as would be used in killing plant 

 lice or aphids. There is considerable advantage in using the kero- 

 sene mixture if one has the apparatus for applying this. Sucji 

 apparatus consists of a tank or vessel to hold the Icerosene, which 

 is to be placed in turn inside of the barrel which hoJds the water, 

 and so arranged that these liquids are mixed in the definite and 

 desired proportions at the time the spraying is made. One serious 

 objection to the kerosene mixture is that the proportion of the 

 kerosene is likely to vary, and at different times one may be giving 

 an increased or decreased percentage of the oil. Another objec- 

 tion to it is that when the operator is spraying with a rod or long- 

 hose and stops for a long time, the oil will rise to the upper por- 

 tion of the hose or spray pole and the water will sink to the lower 

 portion of the tube. Then when he commences to spray again he 

 will, for a few moments, apply pure oil and later pure water until 

 the recently mixed substances appear. This means that during 

 the time of application of pure oil the foliage will be burnt or in- 

 jured, and during the moments of application of pure w^ater the 

 insects will not be killed. We wish to say now that it is much bet- 

 ter to apply insecticides strong enough to slightly injuria the foliage 

 or the plants than to have them so diluted that insects are not 

 destroyed. We should also call attention to the necessity of care- 

 fully following the printed formulae. If the substances are not 

 applied in as strong proportions as we publish they may not be 

 effective in suppressing the insects and as a consequence one loses 

 his time, labor and material. If, however, they are much stronger 

 than that lor which the forraula3 call they may result in killing, 

 not ovAy tl:e insects, but all the plants to which they are ap])lied. 

 We know of several trees that have been killed simply by the 



