No. 5. ] Paris-green as an Insecticide for destroying Caterpillars. 137 



PARIS-GREEN AS AN INSECTICIDE FOR DESTROYING 

 CATERPILLARS. 



{Reprinted from a leaflet issued hy Miss Eleanor Ormerod, Fehy. 1891.) 

 [Paris-green is an arsenical comiDonnd, very mucli like London purj^le, 

 both in composition and also in tlie effect which it has upon insects. It 

 is applicable to caterpillars and other mandibular insects, many of which 

 are very destructive to crops in India. Tlie methods recommended for 

 use in England will no doubt be found to be equally applicable in India, 

 while the recommendations of so well known and cautious an observer as 

 Miss Ormerod will do much to remove the prejudice which is naturally 

 felt against the treatment, on account of its poisonous nature — Ed.] 



"The object in view iu bringing forward the use of spraj'ing with Paris-green is 

 the pressing need which has long been felt of having some kind of application at hand 

 which is cheap and sure in its action, and which can be brought to bear at once when 

 required on any, or all sorts of, moth caterpillars together (whatever their various na- 

 tures or previous histories may have been), and will kill the whole collection of ravag- 

 ing hordes at once, without damaging the leafage. 



" For some years back trials have been made, in many isolated cases, of various 

 kinds of treatment which it was hoped might be of use in lessening this yearly 

 amount of loss ; but, as these experiments tvere seldom carefully recorded as to details 

 or results, they have been of little public benefit. 



" Therefore, aboat the end of February in last year, 1890, at a conference of fruit- 

 growers held at Evesham, a Committee of Experiment was formed, of gentlemen per- 

 sonally interested in the subject (and also qualified practically, as well as scientifically, 

 to superintend experiments in orchard treatment, and report results), in order to try 

 the effect of any kind of sprays, washes, or other applications which they might judge 

 likely to be effective in destroying the caterpillars on orchard trees without injuring- 

 the leafage; and to meet at various different centres from time to time, so that the 

 whole Committee could judge of results of various treatments, and consultation and 

 detailed reports of the method of treatment respectively take place, or be given by the 

 members. 



Paris-green was one of the applications especially selected for experiment, as 

 having been known for many years to act trustworthily as an insecticide in the United 

 States and Canada, and also because, from the Government reports of both countries, 

 we were able to learn all requisite details as to precise methods of application ; and 

 farther, we were most kindly aided iu our experiments by advice from Mr. J. Fletcher, 

 the Dominion Entomologist of Canada. 



" At the meetings of the Committee the several experiences of the members were 

 given, showing clearly that even under careful experiment just the same uncertainty 

 occurred with regard to reliable effects of almost all the applications, as has appeared 

 to be the case for years back. Alum, hellebore, ammoniacal liquor, and many other; 

 applications were tried, and sometimes found useful ; sometimes as, in the case of 

 alum, found occasionally useful, but also, and on very careful trial elsewhere, of not 

 the slightest service ; and later on, when the caterpillar was more advanced, the alum 

 was found to be of no service at all. 



