24 BULLETIN 14*76, U. S. DEPARTMENT OF AGRICULTURE 
CANADA 
According to Crawford and Spencer (12, 60), the following culti- 
vated crops and flowers, in addition to corn, were found to be in- 
fested in Ontario: Dahlia, geranium, aster, golden glow, beets, 
mangels, tomatoes (fruit), beans, oats, squash vines, broomcorn, 
Sudan grass, Early Amber sorghum, Hungarian grass, Mann's Won- 
der sorghum, white clover, and red raspberry. The following weed 
hosts are also recorded by the same investigators: Barnyard grass 
(Echinochloa crus-galli (L.) Beauv.), redroot pigweed (Amaranthus 
retro flexus L.), yellow foxtail (Chaetochloa lutescens (Weigel) 
Stuntz) ; lamb's quarters (Chenopodium album L.), Russian thistle 
(Salsola pestifer Nels., var. tenuifolia G. F. W. Mey.), green foxtail 
(Chaetochloa viridis (L.) Scribn.), lady's thumb (Polygonum per- 
sicaria L.), wild buckwheat (Polygonum convolvulus L.), ground 
cherry (Phy sails heterophylla Nees), orchard grass (Dactylis glom- 
erata L.), Canada thistle (Cirsium arvense Scop.), wild sunflower 
(Helianthus sp.), viper's bugloss (Echium vulgare L.), ragweed 
(Ambrosia artemisiae folia L.), mullein (Verbascum thapsus L.), 
goldenrod (Solidago sp.), old witch grass (Pamicum capillar e L.), 
yarrow (Achillea millefolium L.), burdock (Arctium minus Bernh.), 
and tumbling pigweed (Amaranthus graecizans L.). 
CHARACTER OF INJURY 
The European corn borer, as the name implies, is essentially a 
boring insect, and causes its most important injury by the tunneling 
and feeding of the larvae within the stems and fruits of the plants 
attacked. This injury, when severe, results in the collapse or deterio- 
ration of the parts of the plant affected, and when less severe the 
normal functioning of the injured parts may be interfered with if 
such injury occurs at a critical point. The larvae also feed to a 
slight extent upon the surface of plants, but such injury usually does 
not appear measurably to interfere with the normal growth of the 
host. The specific character of the injury varies somewhat with 
different groups of hosts and will, therefore, be discussed separately. 
CORN 
The character of the injury to corn depends upon the stage of 
growth of the plant when attacked, and also upon the habits and 
preference of individual larvae. In general, however, the most 
important and serious injury is caused by the tunneling and feeding 
of the larvae within the stalks, ear stems, and ears. The larvae 
also tunnel within the tassel, the midrib of the leaf, the brace roots, 
the stubble, and in fact all parts of the corn plant except the fibrous 
roots. They also feed to a slight extent upon the surface of the 
plant, particularly upon the tender leaf blades, tassel buds, husks, 
and silks of the ears, and between the leaf sheaths and stalks. 
INJURY TO THE LEAVES 
Attacks upon young corn plants are characterized by numerous 
small irregularly shaped feeding areas and the presence of very fine 
particles of frass. Minute punctures perforating the epidermis 
