71 



large a proportion of cases from adult feeding injury alone as from 

 larval injury within. Any injury severe enough to cause the falling 

 of the square is as liable to cause flaring as is the larva of the weevil. 

 Flaring results from an unhealthy condition, whatever may be the 

 cause, and is frequently to be seen in squares which are about to be 

 shed, though the} 7 have never been injured by any insect. However, 

 flaring has come to be popularly associated with weevil injury, and 

 must therefore be quite fully considered. 



When resulting from weevil injury, flaring does not begin, as a rule, 

 immediately after the injury, but only within from one to three days 

 of the time when the square will be ready to fall. In especially 

 severe cases of feeding in jury, flaring often results in less than twenty- 

 four hours. Occasionally the growth of the square overcomes the 

 injury from feeding and the involucre, after having flared, again 

 closes up and the square continues its normal development as though 

 uninjured, and forms a perfect boll. More frequently the square 

 gradually loses its healthy green, becoming a sickly yellow in color, 

 and falls in a short time. 



When injured by the feeding of a young larva as the direct result 

 of successful oviposition, flaring has been found in an average of 139 

 cases to take place in almost exactly 7 days from the deposition of 

 the egg. These observations cover the season from June to Septem- 

 ber, when the developmental period averages about 19 days. Fully 

 one-third of the weevil's full development has, therefore, taken place 

 before flaring results. 



FALLING. 



Squares which flare because of injury from larval feeding within 

 always fall, except the small percentage which, though entirely cut 

 off from all vital connection with the plant, still remain hanging 

 thereon by a small strip of bark and gradually become dry and brown 

 upon the plant. Falling is but the natural final consequence of injury 

 or disease (PI. XII, fig. 46). Whatever its cause, it is brought 

 about in exactly the same way as the shedding of leaves by the plant 

 in the fall, by the formation of an absciss la} T er of corky tissue cutting 

 off the fibro- vascular bundles supplying nourishment to the square. 

 The exact location of the cork area is to be seen at the scar left by 

 every fallen square. 



In 539 cases definitely noted between June and September, 1903, 

 the average time from egg deposition to the falling of the square was 

 9.6 days. For this same period full development required an average 

 of 19 days, so that falling occurred at the middle point in the weevil's 

 development. From a comparison of the time of flaring with that of 

 falling it is seen that the interval between these two points averages 

 about 2.5 days. In late fall the time between oviposition and falling, 

 as recorded in 21 cases, was found to be about 16 days. 



