270 Appendix. 



]ihate (lid not give tliis trouble. In applying the two solutions no difference was 

 noticeable, except that the Oregon solution was somewhat thicker ; and their 

 effects, so far as we could ascertain, were the same. It is quite probable that 

 the addition of the copper sulphate to the sulphur and lime does no harm what- 

 ever ; but that it improves the solution in anj' way our experiments have not 

 yet demonsti;ated. 



THOROUGHNESS OP APPLICATION NECESSARY FOR SUCCESS. 



In doing this work care was exercised that every part of the trees should 

 be covered with the solution. Yet it was found that, even when such care 

 was taken, many spots on the trees were left untouched. These places are not 

 easily seen while the trees are wet, but after a day or two the coating of solution 

 turns a yellowish white, making all unsprayed spots very conspicuous. After all 

 the trees had been sprayed, a day and a half was spent in going over the or- 

 chard a second time and in touching up all places that were missed at the first 

 application. The time of this work was short as compared with the time of 

 The first application, which took twenty-one full days. This retouching is very 

 important, as a small place left unsprayed on a tree may hold enough insects 

 to re-establish the pest in a year or two. The trees had been thoroughly pruned 

 previous to the spraying, without which pruning thorough spraying would 

 have been very difficult. 



TIME SOLUTION REMAINS ON THE TREES. 



At the end of one month the trees were as white as wlien first sprayed. 

 Three months from the time of spraying a good coating remained on the trees, 

 and at the end of nine months many trees showed considerable spray. 



COST OF SPRAYING. 



Cost of treatment is always an important factor in deciding what remedy 

 shall be used for theinfested trees. In this instance care was taken not to 

 cut down the cost of the operation at the expense of good work. The best 

 appliances and material that could be procured were used, and yet the cost 

 was not such as to debar their use when compared with kerosene, whale-oil 

 soap, (\v hydrocyanic acid gas. The total cost of the materials and appliances, 

 including the wear of tools, amounted to .$355.00, and the cost of time of men 

 and horses was $321.60; making a total cost of application of $677.50. This 

 amount divided by the number of trees sprayed, or 11.170, gives a cost of six 

 and six-hundredths cents per tree. These trees were all peach or plum and 

 from three to twelve years old. A large part of the trees were full grown. 



RESULTS OF SPRAYING. 



Most of the trees sprayed were not badly infested with the scale, though 

 nearly all had some scale, and a few were considerably crusted. ^Yithin a short 

 time after application, examination of the infested trees showed that the in- 

 sects under tne scale had a shriveled appearance. AYhen pressed with the point 

 nf a knife they were found to be only a shriveled, dry skin, while those on the 

 unsprayed trees were plump. On May 20th. several trees examined showed 

 more than 95 per cent of the scales killed. .lune 20th, the sprayed trees 

 were found practicall.v free from young scale, while unsprayed trees near by 

 showed from twenty-five to two hundred young scale per square inch. At this 

 time some of the old. female scales were found alive on the sprayed trees, but 

 these had not produced young, probably owing to the absence of living, adult, 

 male, scale insects. This would indicate that the female is more resistant to 

 spraying solution than is the male. On November 11th. a careful examination of 

 the sprayed orchard was made. A part of the orchard located contiguous to 

 a badly-infested and unsprayed orchard was re-infested so as to make necessary 



