28 NEW YORK SPATE MUSEUM 
acre. Conditions were so serious that 311 caterpillars were found in 
one hill of corn, 117 in one stalk and 15 in one ear, one caterpillar 
being sufficient to damage an ear seriously. The injury to nearby 
field corn was nearly as great, though sweet corn is much more 
generally grown in the infested area. 
Food plants. There exists no undoubted evidence to show that 
the European corn borer breeds in New York State in any plant 
except corn, though all varieties are subject to attack. The work 
of the insect is most likely to be serious in small to medium varie- 
ties of corn because the larger ones can maintain a greater number of 
borers with less likelihood of severe injury. It should be noted that 
earlier fields of corn are much more likely to be infested than those 
planted later. The principal food plants in Massachusetts, as shown 
by investigations, are sweet corn, field corn, fodder corn, celery, 
beans, potatoes, Swiss chard, beets, spinach, dahlias, gladiolus, 
chrysanthemums, and several of the larger stemmed weeds and 
P grasses, notably barnyard grass (plate 7) and the 
common ragweed, or Roman wormwood. Some 
of these plants become infested simply. because 
they are growing in or near infested corn fields, 
though the pest seems to be able to maintain 
itself upon barnyard grass, dock and lady’s 
thumb. The insect limits itself very closely to 
corn in sparsely infested areas. 
Signs of infestation. The European corn borer 
can be easily detected in corn stalks during the 
winter by the characteristic holes about one- 
eighth of an inch in diameter, frequently with 
discolored margins and usually plugged with bor- 
ings. These entrance holes (figure 1) are most 
easily seen on corn stalks which have been 
stripped of leaves by cattle. The holes lead 
into irregular burrows or galleries (plate 4, figure 
2) x inch to several inches in length, each of 
which is usually inhabited by a yellowish gray, 
Fig. 1 Character- indistinctly lined caterpillar about three-fourths 
istic holes in corn- of an inch in length. The head is brown, and 
stalks as they occur the body minutely spotted with brown. The 
in late summer : 
early fall and SA a galleries that reach to the nodes are frequently 
irregularly enlarged at this point. The borer 
also works in the stubble and may be found in corn fields during 
the winter. 

