INSECTICIDES ON THE SAN JOSE SCALE. 137 



sene limoid) cost $1.66. These are all retail prices. Mixture No. 1 

 cost $0.54 for materials, exclusive of boiling, which can probably be 

 done in large quantities for $0.15 to $0.25 per barrel, according to 

 equipment and conveniences. 



Following our usual custom, twigs from a number of each kind of 

 tree in each locality were examined before treatment. About 35 per 

 cent of the wintering female scales had been killed by the winter. Late 

 in June, just before the appearance of the young, tw^igs were again cut 

 from the same trees and examined. This record showed the kerosene- 

 limoid mixture to have killed about 88 per cent of the scales alive at 

 the time of treatment, while the lime-sulphur washes killed from 91 

 to 95 per cent. These figures, though not marked, indicate the greater 

 effectiveness of the latter, and observations made late in the season 

 not only confirmed the" indications, but shoAved a much greater differ- 

 ence in favor of the lime-sulphur washes. Large peach trees at 

 Southington were sprayed, a portion with the kerosene-limoid mix- 

 ture and another portion with the boiled lime-sulphur wash, the 

 trees being well covered in each case, and all were badly infested 

 with scale. In October I was greatly disaj^pointed to find plenty of 

 living scales on the trees sprayed with the kerosene-limoid mixture; 

 some were as badly infested as before spraying. 



Trees in adjoining rows sprayed with the lime-sulphur wash, 

 though showing some living scales, were comparatively free from 

 them, although there were plenty of dead ones. The evidence seems 

 to show that though the kerosene-limoid mixture had in June killed 

 nearly as great a proportion of the scales as the lime-sulphur washes, 

 it apparently left the bark in a condition much more favorable to 

 the presence of the scale, and therefore to reinfestation, than the 

 latter. I have noticed that where lime-sulphur washes are applied 

 the bark does not readily become again covered with scales; it is 

 also possible that the scales counted as alive in June were injured 

 to such an extent by the lime-sulj^hur wash that they failed to repro- 

 duce. Other expei'imenters haA^e reported similar results. 



Strange to say, the self-boiled wash of lime, sulphur, and sodium 

 sulphide gave slightly better results than the boiled wash. The pres- 

 ence of salt in the boiled wash could not be detected by its effect on 

 the scales nor by its adhesive qualities. 



EXPERIMENTS WITH INSECTICIDES ON THE SAN JOSE SCALE. 



By E. P. Felt, Albany, N. Y. 



The insecticide campaign of recent years has been continued with 

 gratifying results, so far as confirmation of earlier work is concerned. 

 The tests have been limited largely to lime-sulphur washes, boiled 

 and unboiled, and 20 and 25 per cent of the so-called limoid or K-L 



