(d) \Yhere pests are attacking roots, the use of soil fumi- 

 gants or insecticides e.g., the injection of carbon bi-sulphide 

 is sometimes advised, but the results obtainable are un- 

 certain, sometimes hopeful but more often unsatisfactory and 

 it is advised that at present all soil insecticides should oe 

 treated as experimental only. 



Against insects other than those in the soil, fumigation h-is 

 a few special applications e.g., in cleaning stock from pests 

 prior to planting. This, however, requires certain facilities 

 and is better left to the nurseryman. The grower can, how- 

 ever, use fumigants in the case of certain large insects (Leo- 

 pard Moth) which burrow into fruit trees, and it is then no- 

 difficult matter to insert the necessary chemical in the burrow 

 and block up the hole. Further particulars are given in 

 Leaflet No. 60. 



Conclusion. The preceding notes relate solely to insect 

 pests but readers should be warned that the different aspects 

 of fruit-growing cannot be shut off into water-tight compart- 

 ments. To show the bearing of this, brief reference may be 

 made to three points. 



(1) Just as separate varieties of a crop differ in regard to 

 flavour of fruit, character of growth, &c., so they also differ 11 

 their susceptibility to damage by pests. This point has not 

 perhaps been sufficiently realised in the past, but plant 

 breeders are now fully alive to the importance of immunity, 

 and h#ve already achieved some notable successes. Unfor- 

 tunately new varieties of fruit take so long to raise and have 

 to combine such a number of qualities, that progress in pro- 

 ducing resistant varieties must necessarily be slow. Neverthe- 

 less this aspect of pest control should always be remembered 

 and even if new resistant varieties are not forthcoming, much 

 may yet be done by observing the difference in susceptibility 

 already shown by well-known commercial fruits so that kinds 

 may be selected which show themselves more . resistant to 

 the pests prevalent in the district. 



(2) Insects are not the only organisms which attack fruit 

 trees. Fungus pests are often quite as important, and it is 

 thus necessary to control both simultaneously. Fortunately, 

 it is often possible to mix insecticides and fungicides and apply 

 them together, though unless such mixing has been definitely 

 advised it is better to get expert- advice before trying experi- 

 ments, since some mixtures would prove most injurious. In- 

 direct measures for pest control, notably pruning out weak and 

 dead wood, are usually equally valuable in the case of insects 

 and fungi. 



(3) Good cultivation generally has a considerable bearing 

 on pest control. Just as a man when in good health is less 

 likely to contract an illness, so a flourishing plant is much 

 better able to resist the attacks of its enemies, and an addi- 



