THE APPLE AND CHERRY ERMINE MOTHS.* 



p. J. PARROTT AND W. J. SCHOENE. 



SUMMARY. 



During recent years colonies of the caterpillars of the apple and 

 cherry ermine moths have been discovered in considerable numbers 

 in the State of New York. These insects were introduced in ship- 

 ments of foreign nursery stock and appeared in plantations of 

 imported apple and cherry seedlings. According to the records of 

 the Division of Nursery Inspection infested plants have been found at 

 Lockport, Hilton, Chili, Dansville, Rochester, Penfield, Newark, 

 Orleans, Seneca and Geneva in western New York; at Johnstown 

 and Schoharie in the Mohawk Valley region, and at Blauvelt, in the 

 Hudson River Valley. 



From the material that has been collected two species of moths 

 were bred — Yponomeuta malinelhis Zell., which thrives largely on 

 apple, and Y. padellus L., which is a more general feeder, showing 

 preference for hawthorn, plum and cherry. Both species are com- 

 mon and destructive fruit pests in Europe. 



The adult insects are small moths, with snowy white, black- 

 dotted anterior wings. The hind wings are gray or leaden in color, 

 with long fringes on lateral and posterior margins. The wing 

 expanse is about 20 mm. The caterpillars are quite variable in 

 color, ranging from pale to grayish or greenish brown, and they 

 average about 15 mm. in length. They have web-forming habits 

 and live in a common web, and in this they spin their cocoons. 



In the studies on the life history of these insects during the past 

 four years the moths appeared during the first two weeks in July, 

 and oviposition began about the middle of this month. The eggs 

 are deposited in oval-shaped masses near a bud, usually of the 

 current year's terminal growth, and less frequently on the older 

 wood. Hatching takes place in early autumn and the young larvae 

 remain through the winter under the protecting crust of the egg 

 shells. In the spring they assemble among the tender leaflets of 

 an adjacent bud, which they attack. The older caterpillars feed 

 openly on the foliage under the protection of a thin, grayish web. 

 With the need of more food they extend their webs, seizing and 

 involving fresh leaves in a common nest. In severe attacks trees 

 may be defoliated and completely covered with the silken tents of 

 the insects. Pupation took place during the latter part of June and 

 early July and the moths lived from the beginning of July to 

 about the middle of August. 



^' A lopriiit of 'rcclinical P>nllotin Xo. 24. Xovcnilior. 1012. 



[3821 



