138 Journal of Agricultural Research voi. vi. No. 3 



sufficiently to infest all the squares. Hence, any agency which retards 

 the formation of the squares in the early spring does a very serious injury 

 to the crop. While the deformed plants may overtake the normal plants 

 later in the quantity of fruit, this fruit will be produced too late to insure 

 safe maturing. 



Another effect of the deformity which may be of considerable import- 

 ance is the ease with which the plants are split when the two or more 

 branches fork at the same point. This gives a very weak stalk, and a 

 comparatively slight jar will split it. In fact, the weight of a crop of 

 bolls will break many of the plants. 



SUMMARY AND CONCLUSIONS 



From the various observ^ations discussed in this paper it seems that 

 mutilation of cotton seedlings may be produced by any of several insect 

 pests. These consist of a number of species of lepidopterous larvae 

 (cutworms, measuring worms, "woolly-bear" larvse, tussock-moth 

 larvae, etc.), grasshoppers, and leaf beetles. In all fields several species 

 of these pests were present, and in many fields all of them were found. 

 During the spring of 191 5 at Tallulah, La., the tussock larvae were re- 

 sponsible for most of the damage early in the season and then were sup- 

 planted by the grasshopper nymphs. However, the relative importance 

 of the various species undoubtedly varies with the locality and season. 



Tests made with plants protected from low temperatures during the 

 night and from bright sunshine in the early morning demonstrated that 

 the injury would appear about as abundantly on these plants as on the 

 unsheltered plants in the garden and field. Seedlings in large number, 

 raised through this period in pots and crocks containing baked soil, 

 failed to show the slightest trace of injury, although they were fully 

 exposed to the weather. 



Injury to cotton by cutworms has been known for many years, but 

 usually has been considered to consist only of the cutting of the plant 

 stem near the ground. In 1897 Howard * published a brief review of the 

 information then available concerning these larvae, but did not mention 

 them as leaf feeders. In 1 905 Sanderson ^ mentioned the injury due to 

 these worms and also discussed the work of Prodenia ornithogalli. This 

 species he recorded as being diurnal in habits and feeding upon the 

 leaves, but he considered the damage to the squares and bolls as its 

 most important injury. Sanderson also mentioned the "woolly-bears" 

 as occasionally damaging cotton by feeding upon the leaves. 



In actual effect upon the plants it seems that the injury of the various 

 species may result in death of the plant, dwarfing of growth, or defoimity 



iHo-ward, L. O. Insects affecting the cotton plant. U. S. Dept. Agr. Farmers' Bui. 47, 32 p., 18 fig. 

 1897. 

 2 Sanderson, E. D. Miscellaneous cotton insects in Texas. U. S. Dept. Agr. Farmers' Bui. 223, 24 p., 



39 fig. 1905. 



