326 



Journal of Agricultural Research 



Vol. III. No. 4 



df fruit-fly infestation in oranges and lemons in Spain during March or 

 in southern Italy and in Sicily during April, May, and early June is 

 strong evidence that the fruit fly is prevented by the mean tempera- 

 tures prevailing in these countries from becoming a pest during the 

 winter and spring months. Loquats are a preferred host of the fniit 

 fly, being badly attacked when flies are present, and the appearance of 

 infested fruits is such that infestation is easily detected. Even during 

 July at Valencia, Spain, Prof. Ouayle found but a slight infestation of 

 peaches and overripe oranges. In August, near Palermo, Italy, peaches 

 were found badly infested, but lemons growing in the midst of peach 

 trees were not infested. Reports indicate that in Spain and southern 

 Italy the fruit fly may cause some damage to ripening oranges during 

 September and October, although this is slight and of short duration. 

 Citrous fruits, especially oranges, are not usually punctured by the 

 female fruit fly until they are well grown and about to turn color, and 

 the period of time is short after they reach this stage of ripeness until 

 cool weather renders the fly sluggish. The season of the year, there- 

 fore, when the bulk of the citrous crops are best suited for fruit-fly attack 

 coincides with the season of inactivity of the fly due to lower tempera- 

 tures. 



The mean monthly temperatures given in Table VI indicate that the 

 Mediterranean fruit fly would find conditions in the citrous regions of 

 Florida and California quite similar to those in Spain and Sicily. The 

 Florida temperature, especially in the citrous regions of southern Florida, 

 is decidedly above the winter means of those of California. However, 

 even if the temperatures were higher than they are, the writers feel that 

 the fruit fly would assume a minor position as a citrous pest. The cool 

 winter weather would have the same retarding eS'ect upon develop- 

 ment in California and Florida that it has in the European countries. 



Table VI. — Monthly mean temperatures iti citrous regions 



Locality. 



Seville. Spain 



Malaga, Spain 



Naples, Italy 



Palermo, Sicily 



San Francisco, Cal 



Redlands, Cal 



San Diego, Cal 



Portersville, Cal 



Jacksonville, Fia 



Eustis, Fla 



Miami, Fla 



Myers, Fla 



Honolulu, Hawaiian 



Islands 



Prospect Hill, Bermuda. 



