1024 



Canadian Forestry Journal, March, 1917 



ant, Mr. McCubbin, indicate a mea- 

 sure of control exercised by prevail- 

 ing weather conditions. 



This concludes the general con- 

 sideration of the role of the Ribes 

 species. 



From a consideration of the role 

 of these factors we can draw the fol- 

 lowing conclusions as regards con- 

 trol of the disease: — 



(1) Exclusion of all foreign white 

 and other five- leaved pines, which 

 has already been done . 



(2) Exclusion of all foreign species 

 of the genus Ribes according to Gray's 

 Manual, if known to be carriers of 

 the rust, (which has already been 

 done by the United States of Am- 

 erica). 



(3) Examination in plantations, 

 hedges, shelter belts, etc., of all white 

 pines originating from any foreign 

 sources. 



(4) Destruction in any such plan- 

 tation, hedge, shelter, belt, etc., of 

 each and every tree found infected 

 even in the smallest degree. 



(5) Examination of, and destruc- 

 tion, if possible, of Ribes, wild or 

 cultivated, in the neighbourhood, 

 where infected pines may be found; 

 if disease be found, the area should 

 be proclaimed as a danger area. 



Scouting Necessary 



(6) Systematic look-out, during 

 April, May and June, for blister rust 

 on native pines; and from June to 

 October, for currant rust, followed 

 by immediate report and proclama- 

 tion as danger areas, wherever disease 

 b^ found. 



(7) Strict quarantine against the 

 export of white pine or other five- 

 leaved pines from any danger area. 



(8) Strict quarantine against the 

 export of currant or gooseberry stock 

 from nurseries in any danger area, 

 until a license has been granted by 

 an authorized government official 

 that neither stage of the rust has 

 occurred on the premises of the licen- 

 see, whilst, at the same time, all pines 

 have been destroyed throughout the 

 danger zone. 



(9) Destruction of all wild spec ies 

 of Ribes acting as carriers in the 

 neighbourhood of valuable standing 

 white pine timber. 



(10) Planting of deciduous tree 

 shelter belts surrounding new pine 

 plantations. 



(11) Mixed re-afforestation. 



(12) Raising of pine seedhngs, 

 outside of danger areas, for future 

 supplies from home grown seed. 



The last three suggestions are made 

 as additional and rational precau- 

 tions. Shelter belts would protect 

 against the attack of pines by dis- 

 ease; next, mixed planting would re- 

 duce losses in case new plantations 

 may be invaded by disease in future; 

 and my last suggestion is to encourage 

 re-afforestation with young seedhngs 

 grown in this country. 



Duty of Dominion Government 



In order to achieve the best results 

 from these prophylactic measures, 

 the work should iDe divided. The 

 part assignable to the Dominion 

 authorities would be to give the re- 

 quired legislative support, to carry 

 on, by means of their experts, re- 

 searches into many uncertain phases 

 of this important disease, some of 

 which have been briefly referred to, 

 and to act generally as scientific ad- 

 visers and referees to the provinces. 

 Arrangements could also be made 

 for the training of provincial inspec- 

 tors, if such be found necessary. The 

 Field Plant Pathological Laboratories 

 of the Dominion, under my direction, 

 would affort great assistance in this 

 respect. 



To the provinces would fall the 

 maintenance of systematic scouting 

 inspection, the supervision of the 

 eradication of pines or currants as 

 the case may be, the replacing of 

 diseased plantations by young stock, 

 and generally the responsibility for 

 the carrying out of the practical work 

 in their provinces, and the soliciting 

 of close co-operation from all inter- 

 ested parties. 



If all these suggestions are found 

 practicable and economically safe, it 

 would, then, be reasonable to hope 

 that the disease,, which has done such 

 serious damage in Northern Europe, 

 will not prove as appalhng to Am- 

 erica's most valuable lumber tree, 

 as was expressed some years ago by 

 Professor Sommerville, the well- 



