TEE L ANT AN A BUG. 551 



doned plants in waste land thickly colonized by the bug. Superintendants 

 of coffee estates should be on their guard against the introduction of this 

 pest. 



The tea plant fortunately does not appear to be a favourite food of the 

 Orthezia, though, failing more favoured plants, it can subsist and breed on 

 our staple product, and the subsequent generations might very readily ac- 

 quire the taste for Ceylon tea. The danger arises from the enormous and 

 rapid reproductive powers of the insect. When it finds a congenial food 

 plant — such as Lantana — it multiplies till every shoot is thickly tenanted, and 

 the later broods are simply crowd(.d off and compelled to seek fresh pastures. 

 The several instances of the establishment of the pest upon tea have mani- 

 festly arisen in this manner, 



Eemedial Measures. 



The Orthezia is one of, if not the most resistent of all scale-bugs towards 

 insecticides. It is therefore a useful subject upon which to test various 

 treatments. An insecticide that will kill Orthezia can be almost guaranteed 

 against any scale pest. It is remarkable that the half-grown insects will 

 often survive treatment that has successfully destroyed the younger and older 

 individuals. 



In the case of isolated trees attacked by this pest, the gas treatment is 

 really the most effective and complete. This consists in covering the tree 

 with a tent or sheet of some closely woven material, beneath which hydro- 

 cyanic acid gas is generated. The deadly gas will penetrate to every part of 

 the tree and reach every single insect, I have recently ascertained by experi- 

 ment that an extra strength of the gas with a shorter exposure (tlian usually 

 prescribed) is the most certainly fatal to the insects and the least injurious 

 to the plants. The gas treatment however, though really very simple, re- 

 quires considerable care in application, and is subject to certain dangers. It 

 cannot therefore be recommended for general use without previous demon- 

 stration bv a trained operator. 



Spraying is the next best measure. But however thoroughly this work 

 may be done, a certain proportion of the insects is bound to escape, and the 

 process must be repeated at intervals until the pest has finally disappeared, 

 I have found that mixtures of which soap is the principal component are 

 aiore efficacious against Orthezia than any other form of insecticide. Besides 

 killing the insect, the soapy matter blocks the aperture of the ovisac, and so 

 prevents the emergence of the you ig larvae. Kerosine-snap-emulsion is a 

 useful and inexpensive mixture, but requires careful preparation. The for- 

 mula is : — 



Kerosine 2 gallons. 



Common Soap ... ^ lb. 



Water ] gallon. 



