XUST ON THE ORANGE. 137 



to active circulation of sap, the pressure from within 

 induces a more active flow of oil. Hence the rain 

 makes the show of rust the more speedy by first 

 stimulating to an increased flow of oil and then 

 hastening its oxidizing. The rust does not appear 

 simultaneously with the insect, but follows its opera- 

 tions. Hot weather is favorable to the development 

 of the insect, but wet weather increases the show 

 of rust. 



Sulphate of lime I have found to be a specific 

 for the rust-insect. Two applications should be 

 made during the year, one in the spring before the 

 blooming of the trees, the other during the month 

 of June. The sulphate of lime or land plaster 

 should be applied while the tree is wet, at the rate 

 of from one to two quarts to the tree. The whole 

 of the trunk, branches, and foliage should be well 

 dusted. 



