446 



CORN 



weak and unproductive stalks is permitted to be shed it will undoubt- 

 edly be the father of many of the kernels produced on the strong, 

 vigorous looking ears. Weak parentage in the line of our livestock 

 has long been considered undesirable for satisfactory results. It should 

 likewise be eliminated in corn by means of the selection bed. 



CAUSES OF BARREN STALKS. Stalks that bear no ears are 

 called barren stalks. With very few exceptions, they will have a tassel 

 and shed pollen the same as other stalks. Barren stalks are not espe- 

 cially the weak stalks in the field, but very much to the contrary. They 

 may be attributed to several causes, weak seed, insect injuries and 

 diseases, unfavorable soil and climatic conditions, and too thick plant- 

 ing. 



Weak Seed. While many of the barren stalks are of strong and 

 vigorous growth, a few are also found much smaller and weaker 

 in appearance. More than anything else, poor seed is responsible for 

 the weak stalks that appear in the field. A large number of the weak 

 stalks are barren. 



The following table is given in illustration of this : 



The ears used in this table are taken from results at 3 county 

 stations in different parts of Iowa. 



Weak seed produces weak stalks with poor root development, 

 which are seldom able to yield grain. 



Insect Injuries and Diseases. The plant draws the hardest upon 

 the soil at the time of putting forth its shoots and tassels. A corn 

 plant may not have its root system so injured during its early 

 growth, but that the stalk can be very well supplied, and in case of 

 rich ground, a strong, vigorous looking plant may often be produced. 

 Yet at the time when the plant is ready to put forth its shoot and 

 tassel, it is unable to do both because of its roots having been lacerat- 

 ed by insect pests. In such cases, the ear is sacrificed, while with few 

 exceptions the tassel will be present. 



The foregoing is especially applicable to the corn root worm and 

 the white grub. The corn root aphis will accomplish the same re- 

 sults. It does not lacerate the roots, but sucks the nourishment. 

 Chinch bugs coming on to corn just before shooting time, often suck 



