100 G. H. CORBETT. 



It should always be borne in mind that clean cultivation not only prevents, in 

 many cases, the completion of the hfe-history of this insect, but also yields other 

 advantages to the crops. 



3. Insecticide Applications. 



Four insecticides were experimented with, namely, pyridine sulphate, quinohne 

 sulphate, nicotine sulphate, and soap. 



Pyridine sulphate was found unsuccessful. 



Quinohne sulphate possesses insecticidal properties, but the fact that it had to be 

 used in strong solution, and therefore in large quantities, rendered it unsuitable. 



Nicotine sulphate was tried with soap (" Sunhght ") in varying strengths, and the 

 best solution found was one part of 32 per cent, nicotine sulphate to 1,200 parts of the 

 soap solution, which was obtained by dissolving 1 lb. of the soap in 21 gallons of water. 



Soap ("Sunhght") spray, consisting of one pound of soap to ten gallons of water, 

 will kill a large percentage of thrips, both larvae and adults. Soap alone is only 

 recommended if nicotine sulphate is unobtainable. 



It should be stated that spraying is considered impracticable, as well as unecono- 

 mical, when the cotton is four or five months old ; but if the thrips should appear 

 when the plant is small, the nicotine sulphate spray with soap wiU be found very 

 useful. Spraying should be done in the late afternoon and evening, and at least 

 twice, so as to kill the larvae which have hatched from eggs in the leaves since the 

 first spraying. 



