Jan. IS. 19>S 



Citrous Fruits and Mediterranean Fruit Fly 



313 



Table I. — Results of examinations of ripe citrous fruits infested by the Mediterranean 



fruit fly "■ 



Kind of fruit. 



Total 

 num- 

 ber of 

 forms 



ex- 

 amin- 

 ed. 



Grapefruit 



Lemon 



Lime 



Shaddock No. x . 

 Shaddock No. 2 . 



Kusaie lirae 



Sweet orange 



Sour orange 



Chinese orange. . 



7,72a 

 1, 80s 

 1,455 



303 

 1,155 



838 



•3,64s 



2,337 



923 



o These examinations were made sufficiently long after the fruits were gathered to permit all eggs to 

 hatch. All eggs recorded in tables are in reality dead, even though certain of them are marked " normal " 

 in appearance. 



The excessive mortality referred to does not mean that citrous fruits 

 are less attractive to the adult Mediterranean fruit flies or that the fruit 

 of certain species of the Citrus family is not capable of becoming badly 

 infested. Reference to Table I shows that the female fly freely oviposits 

 in grapefruit, lemons, limes, shaddocks, and sweet, sour, and Chinese 

 oranges. Whatever may be the degree of preference shown by the 

 females for other fruits, it is not great enough, at least under Hawaiian 

 conditions, to lead them entirely to ignore citrous fruits, even when 

 these are grown in close proximity to such a favored host fruit as the 

 peach. A study of the data in Table II shows that the female has a 

 much stronger preference for the mango (Mangifera indica) and the ball 

 kamani {CalophyUum inophyUum) than she has for the orange or lemon. 

 While the data are very limited as to the amount and the number of 

 fruits treated, they are indicative of conditions in the field covering 

 a larger range of fruits. In Bermuda during December, 191 3, the senior 

 writer found oranges unaffected while Thevetia and loquats {Eriobotrya 

 japonica) were well infested. Unfortunately for experimental purposes 

 there are in Hawaii no large Citrus orchards free from other host fruits. 

 Instead there are growing a great profusion of host fruits, chiefly in city 

 or suburban districts, which furnish a rapid succession of fruit flies. 

 No matter, therefore, what preference the ovipositing females may show 

 for noncitrous fruits, the flies are present in such large and constantly 

 augmented numbers that the slowly maturing citrous fruits are bound 

 to be attacked. This is especially true during the months of December, 

 January, and February, when a comparatively small number of host 

 fruits other than Citrus are in season. Like conditions also exist at other 

 seasons of the year during the short intervals between the ripening 

 of other host fruits. While many of these host fruits ripen quickly, 

 the citrous fruits, with the exception of the Chinese orange, develop 

 G9733°— 15 3 



