December, '21] morrill: thurberia boll weevil 477 



Representative Answer: "Would destroy few of X and 

 none of Y and would probably force search of food within 

 range of flight of insects X and Y." 

 4. Would it be logical and advisable to destroy the plants B 

 growing within five or six miles of the mouths of the canyons 

 (where infested debris containing weevils X is supposed in 

 many cases to be deposited by water) before the plants B 

 are destroyed higher up on the water shed?" 

 Representative Answer: "No. Should be left as trap 

 and insects destroved." 

 6. Would you characterize the destruction of plants B at the 

 lower ends of the canyons and adjoining washes during Octo- 

 ber and November, with no attempt to collect the adults of 

 weevil X or destroy the larvae and pupae of moth Y in cells 

 in the ground near the food plants or to destroy the plants 

 at higher elevations as (a) a logical and highly commenda- 

 ble action likely to prevent infestation of crop A. (b) as a 

 matter of little consequence from any standpoint or as (c) 

 a colossal blunder diametrically opposed to good ento- 

 mological practice and seriously threatening to agricultural 

 interests'" 



Representative Answer: "As (c)." 

 No one, prejudiced or unprejudiced, has found any detail of the 

 conditions stated in the questionnaire which does not correspond 

 in all essential points with the several publications relating to the 

 subject. However, it should be pointed out that in the second paragraph 

 it would have been more in accord with the facts to have stated that in 

 "most" rather than "some" cases, the water even when in considerable 

 quantities disappears in the sands in or near the lower ends of the 

 canyons. 



Wide experience with the cotton boll weevil has demonstrated that 

 narrow non-cotton zones, such as the Arizona officials have attempted 

 to maintain, are worse than futile in stopping the progress of the weevil . 

 In general, the weevil will cross a five or ten mile non-cotton zone fast- 

 er than it would cross the same area planted entirely in cotton. The 

 weevil and food plant relationships having been disturbed during 

 a critical period and at a place where most easily thrown com])letely out 

 of adjustment, the outlawed cotton plantings which became infested 

 evidently served a most valuable purpose as trap crops. Unfortunately 

 there were too great intervals between these outlaw fields. Under the 

 circumstances which existed the more cotton grown in the prohibited 



