SEVENTEENTH ANNUAL MEETING. 83 



and quince, are densely clothed with soft, downy hairs, among 

 which the insect finds a very suitable hibernating place, where 

 he will be protected from the weather and where he will be 

 able to do the most damage in the spring. 



With the oil, on the other hand, a very fine nozzle may 

 be used and the material may be applied in extremely small 

 particles. This feature, with the spreading quality common 

 to oils, insures greater penetration and allows a wider mar- 

 gin for the careless worker. 



Safety. Next in importance to the efficiency factor comes 

 that of safety. By this term is meant freeness from any in- 

 jurious effects upon the tree. The lime-sulphur wash has 

 seldom been known to cause injury when applied to dormant 

 trees. Many individual growers, and at least one experiment 

 station, have reported slight injury from applications made 

 in the autumn, soon after the leaves had fallen. Under or- 

 dinary conditions, however, it seems quite safe to use the 

 lime-sulphur wash, either late in the fall or early spring. Our 

 experience with oil sprays is somewhat limited, but the various 

 commercial preparations have received a wide trial during 

 the past three or four years and no injury, either from fall 

 or spring applications, has been reported. In consideration 

 of the fact that crude petroleum in its undiluted state is being 

 used by many growlers, w^e should certainly not expect injury 

 from an emulsion containing not more than five per cent. 



The possibility of a cumulative effect upon the trees has 

 been suggested, but this seems to be quite improbable. Careful 

 examination of trees six weeks after spraying with home-made 

 oil emulsion and with some of the commercial preparations 

 has revealed very slight traces of oil residue, probably vase- 

 line. The amount remaining on a tree sprayed with a five per 

 cent, emulsion would be so insignificant that it may be dis- 

 regarded. 



Cost. Before comparing the cost of a home-made oil 

 emulsion with that of the lime-sulphur wash, it may be well 

 to consider the cost of the proprietary remedies. Scalecide, 

 for example, cannot be purchased for less than fifty cents per 

 gallon, by the barrel. At this rate a 1-15 solution would cost 



