BOOK XVII. xxxvn. 230-233 



medlars and pomegranates ; but in the case of the 

 oHve an attack of worm has a two-fold result, inas- 

 much as if they breed under the skin they destroy 

 the fruit, while if they have been in the actual stone, 

 gnawing it away, they make the fruit larger. Rain 

 following the rising of Arcturus prevents their 

 breeding ; and also if this rain is accompanied by a 

 south wind it breeds worms in half-ri])e oHves as well, 

 which are then particularlv liable to fall off when 

 ripening. This happens particularly with oHves in 

 damp localities, making them very unattractive even 

 if they do not drop otf. There is also a kind of gnat 

 troublesome to some fruits, for instance acorns and 

 figs, which appears to be bred froni the sweet juice" 

 secreted underneath the bark at that season ; and 

 indeed these trees are usually sickly. 



Some influences of seasons or localities cannot windbUght. 

 properly be called diseases, since they caase instan- 

 taneous death, for instance when a tree is attacked 

 by wasting or blast, or by the effect of a special 

 wind prevaiUng in a particuhir district, like the 

 sirocco in Apulia or the Olympias wind in Euboea, 

 which if it blows about midwinter shrivels up trees 

 with dry cold so that no amount of subsequent sun- 

 shine can revive them. This kind of blight infests 

 narrow valleys and trees growing by rivers, and 

 particularly vines, ohve and figs ; and when this has 

 uccurred, it is at once detected at the budding season, 

 though rather later in the case of ohves. But it is a 

 sign of recovery in all of them if they lose their 

 leaves ; failing that, the trees which one would 

 suppose to have been strong enough to resist the 

 attack die. Sometimes however the leaves dry on 

 the tree and then come to hfe again. Otlier trees 



161 



