234 FRUTT INSECTS 



The Howard Scale 

 Aspidiottis howardi Cockerell 



This scale insect was first discovered in Colorado in 1894, 

 and now ranks as a serious pest in pear, plum and prune or- 

 chards in that state. It also attacks apple, peach, wild 

 plum, white ash and maple trees ; and has been found in New 

 Mexico. Besides infesting the bark, especially on the twigs, 

 it often occurs on the fruit, causing a peculiar pitting of the 

 surface on pears, and, like the San Jose scale, reddish discolora- 

 tions of the skin around the scales. Trees are sometimes in- 

 crusted and killed by this scale. It is closely allied to the San 

 Jose, the Putnam's, the cherry and the European fruit scales, 

 being distinguished with certainty by microscopic characters 

 only. Mature female scales are circular, about the same size 

 as the San Jose scale, but of a paler grayish color with the dull 

 orange exuvial spot on one side of the center. In Colorado there 

 are three and possibly four overlapping generations of this 

 scale annually, the winter being passed in the partly grown 

 condition. Males emerge early in April and six or eight weeks 

 later crawling young appear. The species is apparently both 

 oviparous and ovoviviparous, usually eggs, but sometimes only 

 minute, living young, being found under the mother scales. 



This Howard scale spreads slowly and is attacked by a little 

 parasite, Prospaltella aurantii, and the twice-stabbed lady-bird 

 beetle as well as small spiders destroy many. The lime-sulfur 

 wash applied late in spring before the buds open has been found 

 to effectively control the insect in Colorado. 



The European Pear Scale 

 Epidiaspis piricola Del Guercio 



This small, circular European scale insect has been sent to 

 the United States several times on nursery stock, but seems to 



