Apr. 17, 1916 



Insect Injury to Cotton Seedlings 



137 



From this it is seen that the percentage of deformed plants ranged 

 from 3 to 10.6, with an average of 8.1. As these same fields furnished 

 the records given in Tables II and III, and were shown in the latter to 

 have practically every plant more or less mutilated, it seems evident that 

 only a comparatively small amount of the injury produces final deformity. 

 However, an injury which deforms only 8 per cent of the plants in a field 

 still is of considerable importance. 



When this deformity was first observed it was at once noted that the 

 injured plants were not forming as many squares as normal plants of the 

 same age and height. Further studies showed this effect to be so pro- 

 nounced that counts were made in the fields to determine the relative 

 squaring of deformed and normal plants. In these observations, every 

 time a deformed plant was found its squares were counted, and likewise 

 those on the nearest eight normal plants of the same size. The average 

 of these normal plants was compared with the number upon the deformed 

 one. In 40 cases out of the 229 recorded the squares on the injured 

 plants exceeded the average of the nearby normal plants, but in all others 

 the average of the normal ones was considerably higher than the number 

 on the injured plants. A summary of these observations is given in 

 Table VI. 



Table VI. — Effect of deformity upon fruiting of cotton plants 



The 229 deformed plants averaged 5.6 squares per plant, while the 1,834 

 normal ones averaged 8.2 squares. This gives a difference of 2.6 squares 

 per plant in favor of the normal plants at the time of these observations. 



From these figures it is evident that the necessity for the additional 

 vegetative development before squaring retards the fruiting of the plants 

 considerably. This is a point of great importance in cotton culture 

 under boll-weevil conditions. The primary requisite for a successful 

 crop in the presence of the boll weevil is early, rapid, and prolific fruiting. 

 This allows the safe "setting" of a crop before the weevils multiply 



