CHAP. XL) THE CONTROL "I INSEt I PESTS OF CROPS. M 



Chapti R XI. 

 THE CONTROL OF INSECT PESTS OF CROPS. 



- ire i|uc les connaissa la c|iicslion parail se 



. i plus en plus : Its observateurs reconnaissent qu'il est impossible dc H 

 ii ii remede general, indistinctement applicable & i ■ >ns les Insecles. Chaqut 

 .int un mode ilc ml- utiles habitudes particulieres, il f.mdra aussi, poui 

 ie preservation et de destru 



/.. s Insectes Enncmis <hs Lt 



ommonest items in an official Entomologist's daily 

 budget of correspondence is ,t letter from some inquirer statin"; that 

 insects are damaging his crop (kind o1 crop usually omitted) and 

 requesting some appropriate "medicine" by return of Post. It 

 need h.irdh he mentioned here that it is quite impossible to appl) 

 any general remedy to meet the ease of all inseel | 

 and that patent "Kill-alls," usually sold at inflated prices under 

 fancy names, belong to the same categorj as the patent medicine 

 " ( in t-. ill- ' so widely advertised under similar conditions. Insects 

 have such widely different habits, some biting and devouring the 

 tissues oi the plant, some sucking its juices, some living on the 

 leaves and others in the stem or below-ground, that it is obviously 

 impossible to apply any general remedy which will be applicable 

 to such diverse conditions. It is necessary to emphasize this fact 

 because in actual experience it is so often found that it is not 

 realized by the general public. 



The control of insect-pests of all kinds is merely the application 

 ot common-sense methods based on a special knowledge of the 

 insects concerned and of any particular details of the circumstances 

 under which they occur ; for example, in the case of insect-pest- of 

 some knowledge of the aKricultur.il practice ol the locality 

 affected, togethei with a knowledge of the life-historj ot the in 

 in question, will often admit the devising of a practical control- 

 measure based on such information, whereas means of control 

 founded merel) on a knowledge ol one of these branches of infor- 

 mation will usuall} prove impracticable. 



The various means of control may be considered under four 



headings, (D agricultural, (2) mechanical. (;,) insccticid.il and (4) 



special, but it may be added that these divisions are only given here 



convenience ol reference and in actual practice they are often 



scarcely differentiated. 



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