THE INSECT CAMPAIGN IO9 



its kind. It is found everywhere, but especially in the 

 northeastern states and provinces of Canada. It is 

 larger than most scale insects and of an irregular ob- 

 long form, which enables one to distinguish it readily 

 from the little round black pimple known as the San 

 Jose scale. It is found especially on old apple trees, 

 but may be found in some cases on young trees the 

 first year from the nursery. The damage wrought by 

 the oyster shell scale is much less severe and summary 

 than that which comes from the San Jose scale, but it 

 is nevertheless very serious. In many cases it prac- 

 tically kills trees or even entire orchards. In this, 

 however, it is nearly always assisted by the systematic 

 neglect of the owner, for the oyster shell scale is sel- 

 dom very serious on orchards well cared for. 



Almost any thorough sort of spraying will check 

 the increase of the oyster shell scale or drive it out 

 entirely. Even bordeaux mixture contains enough 

 lime to make this insect very unhappy, and its con- 

 tinued use is incompatible with the increase of scale. 

 It has been discovered that pure lime whitewash 

 sprayed on the trees in fall or midwinter will prac- 

 tically clean out the oyster shell scale. Any alkaline 

 wash will serve the same purpose more or less efifect- 

 ively according to its composition and the methods of 

 its application. One pound of concentrated lye or 

 crude potash dissolved in 5 gallons of water will do 

 the work thoroughly. The lime-sulphur spray recom- 

 mended for San Jose scale will answer admirably for 

 the oyster shell scale also; but if the latter insect 

 alone has to be fought milder weapons will do as well. 



In giving treatment for any sort of scale insect a 

 preparatory course of pruning and scraping is very 

 important. In the campaign to dislodge the oyster 



