178 OHIO EXPERIMENT STATION: BULLETIN 194 



The species prefers soft maple, though a number of other trees 

 are subject to slight attack, among- the more common being hard 

 maple, honey locust, elm and grapevine. 



Two species very closely resembling the one just described 

 attack the hard maple: the maple leaf scale, Pulvinaria acericola 

 "Walsh and Rileyj and the maple Phenacoccus, PJienacoccus acericola 

 King. ThQ former is found upon the leaves and the latter upon 

 either the leaves or branches. 



Natural parasites play an important part in the economy of this 

 insect, in most seasons being sufficiently numerous to prevent serious 

 damage. However, for some reason the natural enemies are not 

 always successful in developing and considerable harm is done by 

 the scale. When the insect becomes sufficiently troublesome to 

 require attention, winter spraying with kerosene emulsion, contain- 

 ing from 12/^ to 25 percent kerosene, is the remedy most commonly 

 recommended. 



The tests of the value of different spraying materials that have 

 been performed by this department against the insect under con- 

 sideration have been conducted upon trees only slightly infested, 

 so that the results were not as conclusive as they might have been. 

 A clump of soft maples was divided into plots and sprayed during 

 the latter part of March and early in April, 1907. The following were 

 the mixtures applied: Scalecide, 5 percent solution; Scalecide, 3 per- 

 cent solution; Limoid, IS percent kerosene; Limoid, 7/4 percent 

 kerosene; Kerosene emulsion, 12/4 percent kerosene. 



The kerosene-limoid, containing IS percent kerosene, killed 

 practically all of the scales; the kerosene emulsion sprayed plot 

 came next in order of cleanness and the value of the remaining ma- 

 terials is indicated in the following order: Kerosene-limoid, 7J^ per- 

 cent, scalecide S percent and scalecide 3 percent. The weaker 

 solution of scalecide was of little value. 



In another section the merits of the lime-sulfur wash and of 17 

 percent limoid were compared, resulting favorably toward the limoid 

 and in practical failure for the lime-sulfur solution. 



The Ma-ple Terrapin or Black Pf ^^"^^* ^^ sharply hemispherical 



Banded Scale Eulecanium ^^ *°'""' *^^ ^^^^* i&r^^l^ is about 



nigrofasciatum Perg. one-sixteenth of an inch m diameter 



and the color, though variable, is of 

 a general reddish tone with a more or less distinct blackish band 

 near the border. One of the most distinctive characteristics, how- 

 ever, is the peculiar sickening odor that is especially noticeable when 

 the well gr<jwn scales are crushed. 



Soft and hard maples suffer most commonly from th's pest. 



