STALK BORER 235 



broad stripe on each side is characteristic. The pupa stage, which 

 lasts about 2 weeks, is passed in rubbish on the ground. The imago 

 or adult comes forth and begins to lay eggs again in 6 to 8 

 days. This, in all, gives 7 to 8 weeks for the life cycle in 

 midsummer. There are usually from 2 to 3 broods each year 

 in the northern states. The last brood hibernates either as larvae or 

 pupae. The moths appear very early the next spring. 



Prevention and Remedy. Some bacterial diseases attack the lar- 

 vae. Insect parasites destroy great numbers, yet the pest must be 

 combated. If the worms are marching toward a field, a deep furrow 

 in front of them will capture a great many. Holes should be dug 

 in the furrow every 10 or 15 feet. The worms after falling into these 

 holes may be killed by kerosene. In pasture lands, which are smooth, 

 the caterpillars may be crushed by a heavy roller. 



STALK BORER (Papaipema nitela). This caterpillar is very well 

 known. It is sometimes called the "Heart Worm" because of its 

 characteristic attacks, boring as it does into the heart of the stem. 

 It is from an inch to an inch and a quarter long when matured, vary- 

 ing from a purplish brown to a brownish white in color, according 

 to age. It may be told by the white stripes which it bears. These 

 are five in number, one extending along the entire center of the back 

 with two on each side. The stripes on the sides are broken, there 

 being none on the first four segments of the abdomen. This gives 

 it the appearance of being pinched or injured. The eggs which pro- 

 duce these larvae have not as yet been found, but it is commonly be- 

 lieved that the eggs are laid in the fall in grass land, and that these 

 hatch during the same fall or the next spring. When first hatched, 

 the larvae live upon the weeds and grasses which are at hand. When 

 they attack these it is- readily noticed, because the tops of the plant 

 turn to a whitish color, due to the entrance of the larvae within the 

 stem. The rest of the plant may remain green. This is not an un- 

 common sight along the roadsides. As the worm grows in size it 

 looks for new feeding ground where it may find thicker stemmed 

 plants upon which to feed, and in this respect it seems not to be 

 particular. It attacks wheat, oats, timothy, potatoes, tomatoes, rhu- 

 barb, and many other woody stemmed plants. 



Corn is attacked generally when it is from 2 to 15 inches high. 

 A small hole will be noticed in the corn stalk where the stalk borer 

 entered. The burrow within the stem runs upward from this entrance 

 varying in size with the maturing of the larvae. When the cater- 

 pillar is full grown it soon pupates generally within the last plant 



