146 
A Note on the Application of Paris Green as an Insecticide 
for destroying Caterpillars.! 
Nature of the potson. 
Paris green is an arsenical compound, very much like 
‘London purple’’ both in composition and also in the effect 
which it has upon insects. It is more satisfactory than the 
latter compound as it is less liable to injure the foliage, and its 
use has proved safe at the rate of one pound of the Paris green 
to 150 (one hundred and fifty) gallons of water. 
Method of preparing the mixture. 
Before mixing the Paris green with water it is advisable to 
add an equal weight of freshly slaked lime (flour has been 
used instead of lime, but the latter is the better of the two, if 
procurable), mixing thoroughly. The lime takes up any free 
arsenic and prevents possibie injury to the foliage. 
Application of the potson. 
The poison can be best applied by means of an ordinary 
spray pump and nozzle, and during the process of application 
the solution should be kept constantly stirred to prevent the 
poison from settling to the bottom. This is most important. 
Time of application. 
The worms are most readily poisoned when newly hatched, 
and it is therefore very important to spray as soon as the young 
worms first appear. This also, of course, prevents the damage 
which they would commit as a result of delaying. The above is 
a general summary of the nature and method of application of 
Paris green. I will now consider the question more in detail. 
1 This note was written at the instance of Mr. R. Wroughton, Conser- 
vator of Forests, Bombay, with the object of endeavouring to exterminate 
the larve of Hyblea puera and Pyrausta macheralis which defoliate the 
young téak plants reared in the Central nursery near Poona. 
Since this note went to press, | have received information that the 
appication of this poison as here recommended was attended with success. 
