58 CEREAL AND FOE AGE INSECTS. 



REMEDIAL MEASURES. 

 DESTRUCTION OF JOHNSON GRASS. 



The destruction of Johnson grass is one of the most vital factors 

 in midge control. The mere cutting of this grass is not sufficient. 

 It should be burned over wherever discovered, and such areas 

 plowed in the spring to prevent an early crop of heads. 



The practice of allowing Johnson grass to grow within and around 

 areas planted to sorghum is sure to furnish ideal conditions for early 

 and late infestation by the midge, while the small isolated patches of 

 the grass in fence corners will carry the species over winter in the seed. 



CLEAN HARVESTING. 



Careless methods of harvesting the sorghum crop are largely 

 responsible for damage by the midge. It has been pointed out that 

 stalks allowed to stand in the harvested fields will continue to send out 

 until late in the winter branching heads, which furnish breeding 

 possibilities and, later, hibernating material. Again, when the crop 

 is harvested, the stubble should be burned over after all loose heads 

 have been collected and burned. Such heads allowed to lie upon the 

 harvested fields over winter harbor the hibernating midges until the 

 following spring. In many sections it is customary to stack the har- 

 vested sorghum stalks in the field for winter use as a dry fodder. 

 This practice, as can be readily understood, furnishes unlimited 

 possibilities for the midge to successfully pass the winter. (See PL 

 I, fig. 2, and PI. II, fig. 1. 



DESTROYING HEADS OF FIRST CROP. 



Inasmuch as the early crop of seed is practically destroyed by the 

 midge and the second crop matures a very large percentage of sound 

 seed, it is possible that the practice of destroying the first crop of seed 

 and retaining the last crop will yield better results and at the same 

 time eliminate a very great percentage of midges. The fumigation of 

 thrashed seed and storing it in tight receptacles would possibly prove 

 effective in reducing the number of emerging adults from seed stored 

 for planting purposes. 



BAGGING HEADS. 



When a small crop of seed is desired for planting purposes it will be 

 found practical to protect the heads from the midge by bagging as 

 illustrated in figure 22. This should be done before the heads have 

 broken through the protecting sheath, i.e., before the stage illustrated 

 in figure 27, a, and the bags allowed to remain until the seed are 

 mature and hardened. Of course this method is not practical of 

 application on a large scale, but when a small crop is desired it will 

 be found to suit the purpose admirably. 



