290 OHIO EXPERIMENT STATION: BULLETIN 332 



in its action and a plant may possibly be infested for a number of 

 years without serious harm resulting. 



Food plants. This species shows a decided preference for wil- 

 low, but has been reported upon the following hosts : Cornus pubes- 

 cens, C. asperifolia, C. stolonifera, deer bush, big-leaf maple, poplar, 

 Amelancher canadensis and tulip tree. 



Distribution. This species occurs throughout the State and is 

 found throughout the northern section of the United States. 



Control. In the experience of the writer, the standard, liquid 

 lime-sulphur wash used at the rate of 1 part to 7 of water, and the 

 home-boiled sulphur sprays have proved adequate for the control of 

 this species. 



THE DOGWOOD SCURFY SCALE 

 (Chionaspis corni Cooley) 



Description. The appearance of the dogwood scurfy scale is 

 typical of the scurfy group, the female being white and less than 

 one-eighth of an inch in length. (See Plate XLIX, Fig. 2.) The 

 male scale is much smaller, slender and with three distinct ridges 

 extending lengthwise of the body. The eggs are small, oval and 

 purple in color. The winter is passed in this stage. 



Nature of work. For the most part, this species apparently 

 prefers to attack the lower parts of the plant. Occasionally this 

 area is encrusted and parts of the plant die. While not a very 

 serious pest, it sometimes is sufficiently plentiful on some varieties 

 of dogwood in parks to require treatment. 



Food plants. Two species of dogwood have been reported as 

 hosts: Cornus alt erni folia and C. paniculata. 



Distribution. This scale is found in both woodlands and in city 

 plantings. It is encountered more frequently in the northern than 

 in any other section of the State. In addition to this state it has 

 been reported from Massachusetts and Indiana. 



Natural enemies. Hymenopterous parasites are active agents 

 against this species. 



Control. Standard lime-sulphur applied before the buds break 

 in the spring is effective as a control spray. 



THE ELM SCURFY SCALE 

 (Chionaspis americana Johns.) 



Description. The female of the elm scurfy scale differs some- 

 what from the typical scales of the scurfy group ; having something 

 of the general appearance of the oyster shell scale. While originally 

 white, the scale is usually so thoroughly covered with minute bits 

 of refuse that it is very dark gray in color. It is a little less than 



