SlXTEENTir ANNUAL MEETING. 108 



long that it sometimes killed not only the scale but the tree 

 itself. 



This led to further studies and experiments and we learnt 

 a lot about the insects and a1)out the oil. Crude oil as it 

 comes from the soil contains a great lot of products ranging- 

 from the lightest naphthas to paraffine and vaseline; there 

 were almost as many different kinds of crudes as there were 

 wells; certainly no two fields produced the same sort of 

 material. 



Without going into the details of experiments, it was found 

 • hilt to be tolerably safe as an insecticide the crude oil would 

 have to test no heavier than 43 degrees on a Beaume oil scale. 

 Using an oil of that kind on a dry day on a dry tree not below 

 freezing in a fine forcible spray, a thin coating of oil would be 

 api)lied that would penetrate into every crevice, between plant 

 hairs, under bud scales, and, in fact, everywhere on the tree : — 

 and indeed it would "crawl" wherever there was material 

 enough heat to form }-our combination. If you put three 

 light naphthas would penetrate at once under and through the 

 thin edges of the scales and would come into direct contact 

 with the insects, carrying enough vaseline to choke, where they 

 did not at once kill. And then these light oils would evaporate 

 and w^ould leave the heavier products which continued to 

 spread and penetrate until nothing was left except the vaseline 

 and paraffine. This it was that gave the tree its dark, greasy 

 appearance and upon which the moisture would stand in beads. 

 weeks afterward. It was at first considered a distinct advan- 

 tage; but it was found after a time that, den.se as it was, the 

 vaseline still continued to penetrate until it was all gone, and if 

 there were not enough dead surface cells to take it all up it 

 would get into living cells, killing all that it entered. 



When carefullv used on apple and pear, and especially 

 where the oil was first warmed a little, most excellent effects 

 were obtain^ and we have orchardists in New Jersey today 

 who rely mainly on crude oil to wipe out the scale where they 

 have allowed it to get a little ahead of them. They know it 

 will do the required work and they know exactly where the 

 danger lies — and they avoid it. Some of the best crops of 

 apples that were raised in New Jersey last year came from trees 



