MISCELLANEOUS NOTES 287 



induced by some methods of cultivation render the plant 

 under treatment susceptible to disease. 



The old example of the cow selecting the sweetest grass 

 or the grass she pleases, appears to hold good also of the 

 living organisms of the insect world, which are seen to 

 attack in some cases, and to pass over in others, plants 

 in all respects similar. Why ? we do not yet know ; 

 but when we find the answer it will probably render the 

 cultivator capable of maintaining more efficient control 

 over insect pests. 



In the cacao field there are serious problems which 

 require careful study with regard to both insect and fungus 

 attack, in order to regulate the economy of cultivation 

 and the production of good crops. 



Control must be maintained if the best results are to 

 follow, and the planter will be compelled to resort to 

 artificial, until the means of natural control are dis- 

 covered ; but once the latter are known artificial methods 

 must inevitably disappear, on the ground of both economy 

 and safety. The methods of control now known may be 

 stated as follows : 



f Palliative ] ,, 



Artificial control \ Preventive [ :B,xpensive 

 lExterminativeJ^*°g«''°'^ 



Natural control | Effective > g^j^ 



The force of natural control, or of pitting the forces of 

 nature one against the other to maintain a suitable balance, 

 is not yet fully recognised. Wonderful progress has been 

 and is still being made by professors and others ; but 

 professors cannot do all the field work, and the planter 

 should recognise that, in order to manage economically, 

 he should at least possess a discriminatory knowledge of 

 the sciences of mycology and entomology, so as to be able 

 to note in his daily rounds (for use in after practice) the 

 natural means as yet unknown, which he may, and possibly 

 will, find at hand to assist him in the control and working of 

 his estates. 



