romona C>olleae Journal of Entomology 



Volume 1\' 1) K C K M Bl. K I'M: Number 4 



THE COSMOPOLITAN HABITS OF THE FKLIT FLY 



(Ceratitis (^apitata. // V/V/) 



II. \. WKIM.WD 



Of all the [K'sts we have or know of attacking' fruit crops siu-li as thosf 

 trrown in California pi-rhaps the MiMlitfrrant-an Fruit Fly is thf worst. 

 Should it lie ncc^'ssary to inakc a choice of pests, taking the worKl at largo, 

 from wiiich we siioulil likely receive the most damage in this state should 

 it he inipttrted, tho Mediterranean Fruit Fly would without douht he the one 

 ehosen. 



The rea.sons for this are several. One is the fact that tiie attack of a 

 sinplc insect upon a certain fruit ahsolutely ruins that fruit for any purpose. 

 The worst scale or root ju'sts we have may kill the tree in time, may smut the 

 fruit or cause it to he .small or of an interior trrade. hut none of tiiem make 

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

 Another reason is that it is one of the most cosmopolitan in.sccts in its hahits 

 of which the world knows. 



A list of all the fruits of all countri^'s from which it has been hred would 

 he alarmint;ly long and would not present the facts I wish to hrint; forth. 

 The nature of these fruits, the appro.ximate number of tlies per fruit, and the 

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



I base these stat^ements on the conditions i)revailinj; in the Hawaiian 

 Islands for the reason that the conditions are su<'h there that the Hy has ample 

 choice of host fruits and a very suital)le climate, piving valuable liasis for 

 sueh a discussion. 



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

 by decay the fruits her trees produce, in order to hasten the cycle time of those 

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

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

 been created for this purpose even to the tin.v Dro.sophilids or vitM'par flies 

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

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

 flies, particularly the Mediterranean Fruit Fly is that the Drosojiliilids do 

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

 is made in the skin, while this fly bepins earlier in tho pame, often liefore the 

 fruit l)epins to ripen. Thus the Drosophilids are a vahiable a.sset to horti- 

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



