DISEASES OF CITRUS TREES ] 67 



effective barrier. A band of insecticide glue painted 

 round the stem is also useful. 



The locusts (Order Orthopterci) never gave any 

 reason for complaint to the local orange grower. Occa- 

 sionally two or three species make their appearance in 

 the groves, but in very limited numbers. Their green 

 larvae may be seen in spring and early summer skipping 

 upon the weeds and beds of tender vegetables growing 

 near orange trees. The adult insect as well as the larva 

 feed on the same vegetables, but sometimes a few stray 

 individuals may regale themselves upon the tender 

 leaves of Citrus trees, which they seem to relish. These 

 few grasshoppers should always be searched for and 

 killed, to prevent them from multiplying to a dangerous 

 extent, especially in low lying districts with thick 

 vegetation. The migratory locust is known to be deci- 

 dedly injurious to Citrus groves in several countries. 

 Solitary specimens and sometimes small batches of this 

 locust are occasionally seen in our groves, but no real 

 swarms are ever met with. 



Among the Lepidoptera there are three species, 

 Acrolipia Citri, Mill, et Kagg., Albinia Gnidtella, Mill et 

 Farg., and Eupitkecia pumila, H.B., which have proved 

 very injurious to Citrus groves in Italy. The commonest 

 of these butterflies is Acrolipia which is found in Northern 

 Italy, Corsica and Sicily. Their larvae feed upon the 

 blossoms, preferring the blossoms of the lemon tree. A 

 single grub may destroy three or more blossoms, and at 

 times the havoc is so great that the entire crop is lost. 

 The chrysalis hybernates beneath the leaves which it 

 rolls with its web, or in the irregularities of the bark 

 along the trunk and branches. To gather and kill the 

 grubs while on their work of destruction is the only 

 measure which may be recommended ; petroleum or 

 kerosene emulsion has been tried with doubtful results. 

 Fortunately, none of these butterflies has as yet found 

 its way to these Islands. 



