INSECTS AFFECTING OHIO SHADE TREES 175 



, This species is almost well enough 



The San Jose Scale, . . A A 



AsptdwtusperniciosusVom*t. distributed and well enough known 



to render a description unneces- 

 sary. However, it may be stated briefly that the individual 

 scales are very flatly conelike, with a whitish nipple at the apex; the 

 remainder of the scale is gray or blackish and the whole is about 

 the size of a pinhead. When occurring- in large numbers on a 

 branch it gives it a gray ashy, flaky appearance. Additional dis- 

 tinguishing features are that when a tree becomes badly infested, 

 pressure upon the limbs with a knife blade or similar flat instrument 

 causes a yellowish oily liquid to appear. Following infestation the 

 tree assumes a sickly appearance and ultimately dies if uncared for. 

 The length of the period between infestation and fatality depends 

 of course^upon the natural hardiness and the resources of the host. 

 Some trees and shrubs may withstand the burden of attack a con- 

 siderable number of years while others, less hardy, as the peach, 

 may succumb in as few as three years. According to Dr. W. E. 

 Britton, State Entomologist of Connecticut, a little over one-third 

 of the trees, shrubs, and vines grown for fruit and ornamental pur- 

 poses are subject to serious attack from this species, while an ad- 

 ditional third are occasionally or rarely infested. The more com- 

 mon of the plants suffering seriously are as follows: juneberry, 

 hawthorn, privet, poplar, Prunus spp., currant, apple, rose, wil- 

 low, ash, lilac, osage orange and elm. 



The scale is well distributed throughout the State, there being 

 very few counties only from which it is not reported. It is rapidly 

 gaining headway each year, notably in the cities and towns, w r here 

 as yet comparatively little systematic work has been attempted to 

 hold it in check. 



In many parts of the country and particularly in the orchard- 

 ing districts annual spraying is being performed. Where such is 

 the case and thorough work is done the advance of the pest is being 

 checked and the damage reduced to a scarcely perceptible" amount. 



A winter application of the lime-sulfur wash is the safest, most 

 effective and cheapest remedy for this pest. However, by way of 

 modification of the statement concerning the cost of the spray, it 

 should be said that this holds true only where the wash may be 

 purchased at a rate affording no more than a reasonable profit to 

 the maker, or where the area to be treated is sufficiently large to 

 warrant the expense of setting up the boiling plant. Where it is 

 impossible to purchase the wash or where it is impracticable to ar- 

 range a private plant for preparing it, then some of the commercial 

 insecticides may be resorted to. Among washes of this class 



