DISEASES OF CITRUS TREES ] 69 



The fruit-fly attacks not only the orange but many 

 other fruits. The peach, the nectarine, the fig, the pear, 

 the apricot, large sorts of plums, the custard apple, 

 the prickly pear, and sometimes the quince and the 

 apple, are subject to the attacks of this pest. It has- 

 four broods in the year. The hybernating brood appears 

 in autumn, from the last week of September to Christmas, 

 and from this brood the orange" grove suffers severely. 

 When the fruit- fly is about to brood, it chooses the 

 fruit which is exposed to the full action of the sun's 

 rays, because it ripens early and has a thinner peel, 

 which enables the fly to perforate it through its whole 

 thickness by the ovipositor, and often right into the 

 pulp. But in other fruits, peaches nectarines, pears 

 and prickly pears the fly generally chooses that side 

 which is shaded from the sun, because the rind is softer. 

 With the ovipositor at the end of its abdomen the fly 

 pierces the peel, and within the hole thus made, it 

 drops from four to twelve or fifteen eggs which are white 

 and as small as a needle's end. If the sun is shining 

 the small puncture is soon clogged by the juices of 

 the fruit, but on a cloudy day or if the puncture happens 

 to be made in the evening, there oozes out a drop of 

 yellow gummy substance. This oozing takes place within 

 a day or two, and with it the fruit tries to expel the eggs 

 which it contains, which are often seen sticking on 

 the gummy substance exuded from the puncture. If 

 the puncture does not extend beyond the peel and 

 especially if the puncture is followed by the formation 

 of the drop of gummy substance, the eggs do not 

 hatch and the fruit is saved. In the orange, the 

 puncture after some days acquires a yellow colour, 

 afterwards becoming reddish, and is surrounded by a 

 yellowish areola, which disappears completely only when 

 the fruit at maturity acquires its deep orange colour, 

 but the puncture itself is easily recognized in the ripe 

 fruit on account of its paler hue. The fruit pierced 

 by the insect ripens or rather assumes a yellow colour 



