DISEASES OF THI OLIVE TREE ] 113 



bruising or breaking too many twigs, as the strokes are 

 delivered sideways or directed from the inside of the tree 

 to the outside. The olives attain maturity in November- 

 December, but with the exception of the fruit of the 

 <l Bitnia" variety and allied forms, the fruit of all other sorts 

 is hardly ever allowed to ripen on the tree, and is picked 

 in October, when it has nearly reached lull size, but is 

 still green. This is done to anticipate the attacks of 

 the olive-fly of which the earlier broods make their 

 appearance as early as August, but the attack is almost 

 sure to become very acute towards the close of September. 

 A good shower of rain a few days before harvesting, or 

 in the absence of rain, a good soaking of water, greatly 

 improves the appearance of the fruit, which becomes 

 plump and soon acquires a healthy clear* green colour 

 which precedes maturity. The green fruit when pickled 

 or salted keeps better than the ripe fruit, but of course 

 cannot compare with it in point of flavour or digestibility. 



DISEASES OF THE OLIVE TREE. 



Of all diseases to which the olive tree is subject the 

 most important is by far the havoc caused by the olive 

 fly (Dacus Oleae, Rossi; also known as Musca Oleae or 

 Stomomus Keironi order of Diptera). With the only 

 exception of the "Bitnia" olive and closely allied forms, 

 all other varieties of the olive are unfortunately infested 

 by the fruit-fly more or less every year. Normally 25 

 to 50 p. cent of the olives become infected by the olive- 

 fly, but in bad years the infestation may extend practically 

 to the entire crop, hardly any fruit escaping the 

 unwelcome visits of this pernicious insect. The* olive-fly 

 is about half a centimetre in length, being about half th 

 size of the common house-fly. The head is orange- 

 yellow with blue-green eyes, and a yellow front with two 

 black dots; the body is hairy, the thorax is black with 

 two greenish stripes in front, and yellowish spots on eaeh 

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