romona C>ollege Journal of Kntomology 



Volume IV DECEMBER 1912 Number 4 



THE COSMOPOLITAN HABITS OF THE FRUIT FLY 



(Ceratitis Capitata, Jfeid) 



H. A. WEINI;AND 



Of all the pests we have or know of attaekinj^ fruit crops such as those 

 grown in California perhaps the Mediterranean Fruit Fly is the worst. 

 Should it he nee«ssary to make a choice of pests, taking the world at large, 

 from which we should likely receive the most damage in this states should 

 it be imported, the i\lediterranean Fruit Fly would without doubt be the one 

 chosen. 



The r<>asons for this are several. One is the faet that the attack of a 

 single insect upon a certain fruit absolutely ruins that fruit for any purpose. 

 The worst scale or root pests we have may kill the tree in time, may smut the 

 fruit or cause it to be small or of an interior grade, l)ut none of them make 

 at once each and every fruit attacked absolutely worthless as does this pest. 

 Another reason is that it is one of the most cosmopolitan insects in its habits 

 of which the world knows. 



A list of all the fruits of all countries from which it has been bred would 

 be alarmingly long and would not present the facts I wish to bring forth. 

 The nature of tliese fruits, the approximate number of flies per fruit, and the 

 adaptability of each as a host is rather the topic of tiiis discussion. 



I base these statements on the conditions prevailing in the Hawaiian 

 Islands for the reason that the conditions are .such there that the fl.v has ample 

 choice of host fruits and a very suitable climate, giving valuable basis for 

 such a discussion. 



First, let me sa.y that one phase of Nature's plan seems to be to destroy 

 by deca.v the fruits her tre(;s produce, in order to hasten the cycle time of tho.se 

 elements of which the fruits are composed, getting them back into the soil 

 to be used in future crops. The whole family of fruit flies seems to have 

 been created for this purjiose even to the tiny Drosophilids or vinegar fiies 

 which we have all over the world and which are so connnon wherever there 

 is decaying fruit. The only diflFerence between this family and other fruit 

 flies, particularly the ilediterranean Fruit Fly is that the Drosophilids do 

 not begin their work till natural decay sets in or until some bruise or abrasion 

 is made in the skin, while this fly begins earlier in the game, often before the 

 fruit begins to ripen. Thus the Drosophilids are a valuable as.set to horti- 

 culture, while some of the higher forms are an extreme pest. 



