HOW THE SCALE SPREADS. 



This insect moves from one place to another only while in the 

 crawling stage. At this time it may be caught by a gust of wind and 

 carried from one tree to another, or it may crawl onto the feet of 

 some bird or insect which has alighted on the infested tree and crawl 

 ofiF at some later resting place, which of course may be near by or 

 more distant. In general, however, the scale is first brought to any 

 locality on infested nursery stock and from this spreads to the neigh- 

 boring trees and shrubs in one or another of the ways already 

 mentioned. 



TREATMENT. 



When a tree or plant is nearly dead, the best treatment is gener- 

 ally to cut it down at the roots and burn it. Possibly it could be 

 saved by the proper treatment, but it would be several years before 

 it would recover sufficiently to be of any value. For trees less 

 infested many methods have been tried. These naturally fall into 

 two classes, — fumigation and spraying. 



FUMIGATION. 



This in many regards is the most satisfactory method of treatment 

 for infested trees. The poisonous gas penetrates where no spray 

 could reach, and when properly managed kills all the scales. Unfort- 

 unately, it is not usually a practicable method in orchards and as a 

 rule its use is limited to nursery stock. In order to fumigate suc- 

 cessfully gas-tight tents must be used unless the trees are to be dug 

 up ; the chemicals must be of a definite strength, and the fumigation 

 must be conducted by someone familiar with the process. The cost 

 of tents large enouglj to cover orchard trees is usually prohibitive in 

 Massachusetts. 



SPRAYING. 



The results of spraying for the San Jose' scale made in 1902 at' 

 Amherst were given in Bulletin 86 of the Hatch Experiment Station, 

 but as that bulletin is now out of print they are included here ' 

 together with later work in the same line. 



The first spraying was done between March 24th and April 5th, 

 1902. Six hundred and twelve trees were treated, the kinds being 



