PAKT I. 

 THE SAN JOSE SCALE. 



(Aspidiotus perniciosus, Comstock.) 



Introduction. — The San Jose Scale (pronounced San Ho-zay) is 

 widely distributed in North Carolina and does great harm to orchard 

 trees which become infested, unless they be thoroughly and jjersistently 

 treated. In order to combat it to the best advantage some knowledge of 

 its life-history, habits, means of spread, etc., is necessary. If any one, 

 after reading this Bulletin and carefully examining his trees, becomes 

 convinced that they are infested, he should cut some of the infested twigs 

 and mail them to this office for examination. 



Appearance of the Insect.— Trees that are badly infested with the 

 San Jose Scale appear as if they had been dusted over with ashes. If 

 the branches and twigs where the insects are numerous be scraped with 

 a knife it will be seen that this unnatural covering is quite easily 

 removed, coming off in little flaky patches. Examined under a hand 

 magnifying-glass the thickly infested twigs present an appearance as 

 shown at h in Figure 1. Each of the little circular gray objects is a 

 separate scale, each covering a tiny yellow insect underneath. On 

 thickly infested branches they often become so crowded that the scales 

 are piled over one another so that the real bark of the tree is not visible 

 at all. Branches and twigs which are only slightly or moderately 

 infested will not be thus completely covered over, and the bark may be 

 of its ordinary color and appearance except here and there along the 

 branches where the scattering scales are found. The largest full-grown 

 scales are about the size of an average pinhead. They can, therefore, be 

 detected by any person who has in the beginning an intelligent idea of 

 the insect, has sharp eyes, and who happens to look in the right place. 



Usually the farmer or fruitgrower does not know that there is any 

 serious trouble until the trees begin to die. By that time they are cov- 

 ered by the scales and present the ashy appearance. Then, if the owner 

 finds that his trouble is San Jose Scale, he is apt to think that it is only 

 on those trees that present the unnatural appearance, when in reality it 

 may already be on every tree in the orchard. Such a mistake often costs 

 the lives of many trees, since the owner, instead of examining closely 

 and treating every infested tree, as he should do, simply takes out those 

 which are already in dying condition, and then, because he sees no more 

 of similar appearance, he imagines he has exterminated it, when as a 

 matter of fact other trees moderately or slightly infested still stand in 

 the orchard and soon begin to die, having in the meantime spread the 

 insect into still other trees, and so on, until the whole orchard may be 

 ruined. 



Where the scales are not numerous enough to crowd one another each 

 individual grows to somewhat larger size than when they are crowded. 



