30 PKOLTFERATION IN CONTROL OF BOLL WEEVIL. 



little doubt that tho anthracnose (PI. Ill, fig. 12) was the cause of the 

 proliferation. In an examination of 1,800 bolls 71 locks showed pro- 

 liferation from anthracnose. Undoubtedly various species of fiuigi 

 find favorable ])laces for attack in the cavities formed by o]:)en feed- 

 ing punctures, and these also appeared to incite proliferation in 

 man}^ cases, though it is possible that their attack accompanied 

 rather than caused the proliferation. In still other cases decay 

 seemed to be the inciting agent, but whether by chemical stimulus 

 or in some other way is not known. 



ARTIFICIAL STIMULATION TO PROLIFERATION. 



In order to determine positively whether the formation of prolif- 

 eration was connected specifically with weevil attack, a series of 

 experiments was undertaken to see if it could be produced by artifi- 

 cial stimulation without the intervention of any insect. The experi- 

 ments, as originally planned, were miu-h more extensive than is shown 

 by the figures which follow, but unfortunately a considerable portion 

 of the records was destroyed in the field through the vandalism of 

 some unknown person. The records secured are sufficient, however, 

 to indicate reliable conclusions to be drawn from the work. 



METHOD OF TREATMENT. 



Punctures of two sizes were made in these tests, the smaller by a 

 No. 12 needle, which is the smallest size that is commonly used. 

 This needle is not as thick as the proboscis of a weevil, and it made a 

 small puncture. The hypodermic syringe needle used would make a 

 larger puncture than that ordinarily made by the weevil for ovi- 

 positing, but not as large as is often made in feeding. The needles 

 were sterilized in a flame before starting a series of experiments, but 

 not between the punctures made in the series. 



The "sealing" referred to in Table X, column 1, was accomplished 

 by using a solution of shellac in alcohol. This was not supposed 

 to resemble in nature the mucous secretion used by the weevil in 

 sealing her egg punctures, but was simply expected to close the 

 Junctures approximately as tightly as does the weevil. However, 

 the shellac solution accomplished this object only partially, as in 

 many cases it soon peeled away from the surface of the bud or boll. 

 Only a single jnincture was made in each square treated, but in more 

 than one-third of these squares a weevil puncture was present also. 

 The effects of a few chemical solutions when injected into buds or 

 bolls were tested also in these experiments (PI. IV, figs. 13, 14). 



