16 MASS. EXPERIMENT STATION BULLETIN 189. 



Emphasis should be placed upon the fact that the great variety of food 

 plants attacked will undoubtedly prove a serious complication in the 

 problem of controlling the insect. 



Several of these food plants or their products, notably sweet corn 

 (green), field corn (on the cob), celery, beet tops, beans (string beans), 

 Swiss chard, oat straw (used as pacldng material), dahlias, gladioli and 

 chrysanthemums, are commonly transported through the regular chan- 

 nels of trade, and may easily serve as agencies for carrjdng the insect 

 into new localities. 



CHARACTER AND EXTENT OF INJURY. 



Corn, 



The following explanation, concerning the terms herein applied to 

 different parts of the corn plant, maj' be of assistance. The corn plant 

 is monoecius, bearing both staminate (male) and pistillate (female) flowers, 

 separate, but both occur on the same plant. The corn tassel bears the 

 male flowers and the corn silks are the female flowers. The cornstalk 

 consists of nodes (joints) and internodes (intermediate spaces). A single 

 leaf grows from each node. Each leaf is composed of three distinct 

 parts, — the sheath, the Ugula and the blade. The sheath is the part 

 of the leaf surroimding the stalk, and, beginnmg at a node, extends up- 

 ward nearly to the next node, where it joins the long narrow blade of the 

 leaf. Although the sheath surrounds the stalk, the edges merely overlap 

 and are never grown together. The ligula is a thin, upward continuation 

 of the sheath, above its junction wdth the blade, at the point where the 

 sheath ends and the blade begins. The blade is the broad, flat portion 

 of the leaf. The pedicel is that portion of the plant by which the ear 

 is attached to the stalk. The pith is the soft, cork-Uke substance filling 

 the interior of the stalk, between the internodes. 



Kinds of Corn injured. 



In Massachusetts the larvse of the European corn borer have been 

 observed to attack sweet corn, field corn and fodder corn. 



In the area now infested by the insect, sweet corn is grown to a greater 

 extent than either field corn or fodder corn, and most of the observations 

 herein recorded were made on sweet corn. 



Wherever field corn has been found within the infested area the plants 

 have been attacked by the insect with the same degree of severity as has 

 been sweet corn, and, due to its longer period of growth, the damage to 

 the ears is much greater than to the ears of sweet corn. 



Only one field of fodder corn was located within the infested area, and 

 this was attacked by the insect to a slight extent. This infestation was 

 on the edge of the infested area in the town of Topsfield, where only an 

 occasional larva of the European corn borer was found. 



