DISEASES OF CITRUS TREES ] 71 



from the second brood are the precocious figs, known as 

 St. John's figs, early varieties of peaches and nectarines, 

 and sometimes the late lemons, the early apricots and 

 the loquat. 



The warmth of summer causes a third brood to 

 form in quick succession, so quick indeed that 'the 

 third brood is often included in the second, but it can 

 be proved experimentally that there is a distinct brood 

 at about one month's interval from the second. The 

 third brood is developed (i) on figs, particularly the 

 reddish and brown sorts, the black, the violet and the 

 white varieties being apparently less frequently attacked, 

 (2) on peaches and nectarines and on the late large- 

 fruited apricots, of which often not a single fruit is left 

 in a well-stocked orchard, (3) on pears, quinces and 

 sometimes on apples, (4) on prickly pears and late 

 ripening sorts of plums, as well as on the custard 

 apple and on the Kaki or Japanese persimmon. 



From the larvae of the third brood are produced 

 the flies which attack the Citrus grove in autumn, 

 where the fourth and last brood is developed. When 

 the fruit of the round varieties of the orange is attacked 

 by the fruit-fly towards the close of autumn, the 

 attacked fruit may rot on the tree without dropping, 

 and then the larvae may complete their metamorphosis 

 within the fruit, which though quite dry and mouldy, 

 may thus be an unsuspected hiding place for the 

 hybernating pupae throughout the winter. 



The mandarin orange on account of its thin rind 

 is very liable to suffer from attacks of the fruit- fly; 

 the sweet orange and the egg oranges are more subject 

 than the round oranges and the seedless oranges. The 

 bitter or Seville orange is more subject than the lemon, 

 and both are more often attacked in spring than in 

 autumn. Mandarin trees growing in sheltered and warm 

 situations are often deprived of all their fruits, particularly 

 in dry and hot autumns. 



