422 INSECTS INJURIOUS TO THE ORANGE. 



the orchard is large, it will pay to purchase an efficient instru- 

 ment for this purpose. It is stated that, with a suitable pump 

 and nozzle for spraying, from one to two hundred trees can 

 be thoroughly treated in a day. 



Since by far the greater portion of the injury caused by 

 insects to orange-trees is effected by the scale-insects, it is im- 

 portant that prompt measures be adopted to destroy them, 

 and that every precaution be taken to prevent their introduc- 

 tion into districts hitherto exempt from them. Many localities 

 have been colonized by these pests through the return of 

 empty fruit-boxes from infested districts. These may be dis- 

 infected by dipping them for at least two minutes in boiling 

 water containing not less than one pound of potash or half a 

 pound of concentrated lye to each twenty-five gallons. These 

 insects are also frequently disseminated by the transportation 

 of nursery stock from one part of the country to another. 



Sickly trees are more predisposed to attack than healthy 

 ones; hence the use of fertilizers to induce a vigorous growth 

 has been suggested as a remedial measure. In planting new 

 groves, avoid the vicinity of diseased trees if possible, as the 

 young lice are liable to be carried some distance by winds, or 

 on the feet of birds visiting the trees. 



