CORN ROOT WORM ^U 239 



due to the decaying and rotting of the root system, which is always 

 the case where the roots have been attacked. In this condition, the 

 roots are unable to support the plant with proper nourishment for 

 maintaining the growth of the stalk, and at the same time for putting 

 forth an ear. Due to the lack of support necessarily brought about 

 through the injury to the root system, the plants are very easily top- 

 pled over, and are found lying in all directions, especially after a hard 

 rain. Should there be a brisk breeze whole fields are often laid low 

 (See page 246), when if it were not for the corn-root worms they 

 would not have shown the effect in the least. 



When corn that has not been affected by the corn-root worm has 

 been blown down, it is usually found that if the ground is firm, the 

 corn stalk is broken some distance above the surface. The corn roots 

 remain intact, that portion of the stalk below the break remaining 

 in an upright position. When the corn-root worms have been work- 

 ing on the corn, this breaking of the stem does not occur. The whole 

 plant falls. The stubby roots may often be seen protruding from the 

 dirt about them, and the top of the plant endeavoring to take an up- 

 right position, as shown in picture (page 246). .i?''-;' "<?5,'i 



When the ground has been in corn but one year the dartiage will 

 not be particularly apparent the year following. Quite frequently ^he 

 presence of the corn-root worm is not suspected until the small grass- 

 green beetles are found upon the plant. These beetles begin coming 

 forth about the time, or a little before the plant puts forth its shoots 

 and tassels, and will be found feeding on the silks and pollen. It 

 is very common to find fields which are termed "old" and "run out" 

 so that they will not produce corn, which are nothing more or less 

 than lands which are suffering from the ravages of the corn-root worm. 



The hills of corn as shown on page 238 represent the average of 

 the fields from which the samples were taken. Each bundle in the 

 picture is composed of four representative hills from fields which had 

 been in corn i, 2, 3, and 4 years respectively. The 4 hills appear 

 separately in the following cuts. The great variation in the strength 

 of the root system and the number of corn-root worms taken from 

 nills representing ground in corn for the first', second, third, and 

 fourth years will be noted. Each hill was secured by putting a 

 12-inch spade in the ground full length around the entire hiir'at a 

 radius of 12 inches, after which the plants were pulled up. Then 

 the roots were placed upon a sheet; also the loose dirt out of the hole. 

 This experiment was begun July 26, 1906. Many of the larvae having 

 left the roots and entered into the pupa stage, were found in the loose 

 dirt. 



