476 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



"The active period for the adults of insects X extends from July 1 to 

 November 15th^ varying with the elevation and climatic conditions. 

 The adults hibernate inside the ripened and dried fruit of plant B. 

 The adults of insects Y are active during July and August, the worms 

 going into the ground in September and October where they transform to 

 pupae, in which condition the insects spend the winter. The larvae 

 reach full size and go into the ground between September 1st and Oc- 

 tober 15th according to present knowledge of the insect's life history. 

 "So far as known neither insect X or insect Y has any other food 

 plants than A and B. Crop A is grown in several irrigated valleys of 

 limited acreage separated by stretches of desert of from. 50 to 100 miles in 

 each case. The total value of crop A grown within 250 miles of this 

 locality is above fifty million dollars. The plant B is found in the close 

 proximity to only one of these valleys. 



"With the foregoing conditions in mind will you please give your 

 opinion in regard to the following points : 



1st. If there were no other insect or insects than weevil X to be 

 considered, during what period of the year could the destruc- 

 tion of food plant B by " chopping out" and burning the plant 

 be carried out over the whole or a part of the insects' range 

 without danger of forcing a migration of adults to crop A?" 

 Representative Answer: "Novem_ber 15 to July 1" 



2. If there were no other insect than Y to be considered, during 



what season, if any, could the destruction of food plant B be 

 carried out over a whole or a part of its range without danger 

 of forcing a migration of the insects to crop A?" 

 Representative Answer: "Destruction to be of value 

 should be conducted during July and August, leaving trap 

 plants which should be sprayed or the larvae feeding on them 

 killed. Destruction of the plants between Septem,ber and 

 following July would probably force migration of moths 

 coming from hibernation in soil." 



3. Assuming that the worms and pupae of Y in the ground near 



the plants thus destroyed were left undisturbed and assiuning^ 

 that no attempt was made to collect the adult weevil X 

 from the plants before they were chopped out by common 

 laborers, what would be expected as a natural consequence 

 if the wild food plants, B, were destroyed during October 

 and November ?"2 



'The first killing frost may be considered as definitely ending adult weevil activ- 

 ity. The average date of this at Tucson is November 22. 



^The eradication campaign was started on or about October 13, 1919. Fortu- 

 nately, the first killing frost occurred on November 9. 



