DISEASES OF CITRUS TREES ] 65 



a piece of cloth, or brushed away with a wire brush or a 

 chain-glove. 



HAVOC AND DISEASES CAUSED BY ANIMALS. A great 



deal of havoc is often caused to the ripe fruits 

 by rats, particularly by the brown rat. During 

 winter when there are no other fruits and no ripening 

 crops to allure them, the rats resort in large numbers to 

 the orange groves, and their presence is soon made 

 evident by half-eaten oranges and empty peels hanging 

 on the tree. The rat rarely contents itself by feeding on 

 the dropped fruit, but usually takes to the tree, selects a 

 fine fruit, gnaws off a hole in the peel and scoops out the 

 pulp, and ordinarily finishes off that fruit in the following 

 night before attacking another. This habit affords a 

 ready means to destroy the vermin, and by throwing a 

 pinch of arsenic into the half finished fruit, next night the 

 rat will find a poisoned mess for its repast. 



The common snail Helix aspersa eats off in the peel 

 circular holes large enough to admit the tip of a finger. 

 The fruit thus damaged cannot remain long on the tree 

 and is unsaleable. The havoc is sometimes considerable, 

 and the crop of a tree may be destroyed entirely in this 

 manner. The snails may be picked up early in the 

 morning, and crushed or thrown in water with some 

 paraffin. The common hedgehog, which feeds upon snails 

 with avidity, will be a useful auxiliary when present. 



Coleoptera. None of the Coleoptera is really inju- 

 rious to Citrus fruits in these Islands. The two beetles 

 Epicometis squalida Scop, and Leucocoelis funesta Poda, 

 as well as the beautiful chafer Potosia metallica F., are 

 occasionally found feeding on the blossoms of Citrus 

 trees, but "the injury caused by them is too slight to 

 merit consideration. We have no wood-borers of Citrus 

 trees. Other beetles prey upon the twigs and leaves of 

 the orange in America. Hubbard in his work on the 

 insects affecting the orange-tree, mentions two species 

 of Coleoptera, Chion cinctus, Drury, and Oncideres 



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