SPEAYING FOK WOOLLY MAPLE-LEAF SCALE. 161 



(3) With 67.5° F. as the average daily mean temperature, the 

 average period of incubation was seven days and one hour. The 

 extremes in duration of incubation period of five days as the mini- 

 mum and nine and a half days as the maximum corresponded with 

 extremes in average daily mean temperature of 73.1° and 61.3°, 

 respectively. Within this range 1° F. decrease corresponded with 

 0.32 day's increase in the incubation period. 



(4) The average duration of the immature stages of seven speci- 

 mens, with an average daily mean temperature of 61.5° F., was 

 forty-six days. The average adult life of a male and a female speci- 

 men was forty-eight days. 



(5) The two specimens of spined soldier bug under observation 

 destroyed, during their last nymphal instar of six days, 26 elm leaf- 

 beetle larvae. During their adult life the same bugs destroyed 220 

 elm leaf-beetle larvae and 7 large caterpillars. 



DESTKOYING THE WOOLLY MAPLE-LEAF SCALE BY SPRAYING. 



By W. E. Britton, New Haven, Conn. 



The woolly maple-leaf scale, Phenacoccus acericola King (for- 

 merly Pseudococcus aceris Geoff.) has become quite a serious pest of 

 the sugar-maple street trees in New Haven, Hartford, Bridgeport, 

 and other Connecticut towns and cities. 



On August 2 a New Haven seed firm sent me some maple leaves, 

 brought in by one of their customers, which were infested with 

 Phenacoccus acericola. I immediately visited the place. A sugar 

 maple of 10 or 12 inches in trunk diameter was thoroughly infested, 

 and many leaves had already dropped. Scarcely a leaf was free 

 from the white waxy mass containing female and eggs, which are 

 formed on the under surface. The upper portion of the trunk was 

 completely covered with the larvae. Two other small trees near by 

 were infested, though less seriously. The owner was afraid that the 

 trees would die, and wished to save them. As very little has been 

 published about remedies, and as I had not then noticed Professor 

 Cooley's paper a giving his experience with remedial treatment in 

 Massachusetts, I advised that the tree be sprayed with ordinary 

 kerosene emulsion. This was done on August 4, the mixture used 

 containing 2 gallons of kerosene, -| pound of common hard soap, and 

 1 gallon of water as a stock solution, which was diluted nine times 

 before using. On going to examine the trees a few days later, the 

 owner informed me that the spraying did no good, and I almost 



a Notes on some Massachusetts Coccidse. By R. A. Cooley. Bui. 17, n. s.. 

 Div. of Ent, U. S. Dept. Agric, p. 61, 1898. 



31024— No. 60—06 m 11 



