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BULLETIN OF 

 MASSACHUSETTS BOAED OF AGEIOULTUEE. 



SOME IMPORTANT SCALE INSECTS. 



By Dr. H. T. Feenald, Professor of Entomology, Massachusetts Agricultural 



College. 



During the past fifteen years injuries to plants, shrubs and trees 

 by scale insects have become very noticeable, and several of the 

 worst pests belonging to the group have made their appearance in 

 this country and have caused the loss of millions of dollars, often 

 because their small size enabled them to escape notice until it was 

 too late to save the plants they had attacked. The destruction 

 caused by these insects has attracted much attention recently, and 

 in Massachusetts the demand for information concerning them has 

 exhausted the entire edition of two previous articles on this sub- 

 ject, published in the Crop Report.* Since these articles were 

 written additional facts about some of these pests have been learned, 

 and we now know better how to keep them in check. 



The San Jose Scale. 

 {Aspidiotus perniciosus Comst.) 



The home of this, perhaps the worst scale pest, was long un- 

 known, but it now seems probable that it is a native of China. In 

 the United States it was first discovered in California, where it 

 seems to have appeared about 1870. In 1880, when it was first 

 described. Professor Comstock, after giving the detailed descrip- 

 tion of the insect, wrote : " From what I have seen of it, I think 

 that it is the most pernicious scale insect known in this country," 

 and this opinion has certainly been sustained by its subsequent 

 history in the United States. 



In 1893 the scale appeared in Virginia, having probably been 

 received there from New Jersey, and two nurseries in the latter 

 State proved on examination at this time to be infested with it. 

 These nurseries had been experimenting with plum stock from 



* May, 1901, and June, 1902. 



