FOOD PLANTS OF THE GIPSY MOTH IN AMERICA... 9 
The tray experiments were not satisfactory because of the difficulty of secur- 
ing a satisfactory food supply, but all the larve grew well in the early stages. 
Red birch is a favored food plant. 
YELLOW Brircu (Betula lutea Michx. f.). 
Except in heavy infestations, most of the feeding on this species by gipsy- 
moth larvze is done in the first three stages. The larve make small holes, 
extending entirely through the leaves, forming ‘‘ pinholes,’ and a few days 
later “shot holes.” If the infestation is bad and the associated species of food 
plants are defoliated, these birches are sometimes stripped. 
In tray experiments male moths have been secured by feeding larve started 
in the first stage. 
HicgH BLACKBERRY (Rubus sp.). 
Field observations indicate considerable variation in feeding on this plant. 
Defoliation has seldom been reported, and then only when heavy infestations 
occurred. Under ordinary conditions the feeding on this species is very slight. 
Low BLuEBERRY (Vdccinium vacillans Kalm.). 
Of the three species of Vaccinium under observation in this series of experi- 
ments, this is the most unfavorable. Larve in the field have been found 
feeding in all stages, but not to any extent, except in medium to grossly 
‘infested territory. Usually the last three stages do most of the feeding on 
these shrubs. | 
First-stage caterpillars fed in trays have produced moths, which indicated 
that the insect can survive on this species. 
TALL BLUEBERRY (Vaccinium corymbosum L.). 
All the field observers consider V. corymbosum more susceptible to gipsy- 
_ moth attaek than V. vacillans, but it is not favored when other food is avail- 
able. When an infestation is fairly heavy it is not uncommon for these shrubs 
to be entirely denuded. ‘ 
First-stage caterpillars have developed to the adult stage when fed in trays.’ 
The larve did sale grow as rapidly as is normal and were undersize. 
BLUEBERRY (Vaccinium angustifolium Ait.). 
The field observers pronounce-this species the most susceptible to moth 
attack of our three common species. They note feeding in the early as well as’ 
the late stages, and the shrubs may be found in all stages of defoiiation. 
When a tree has been completely defoliated by the larve and they migrate to 
another tree, these shrubs furnish food for the journey. 
First-stage larve fed in trays grew rapidly and large vigorous adults 
resulted. 7 
Box Exper (Acer negundo L.). 
No field observations are recorded on this species. 
Tray experiments indicate that this is one of the most susceptible of the 
maples to moth attack. The larve fed freely in all stages and grew to large 
size; specimens started in the first stage produced moths. 
92719° 15-2 
