Canadian Forcslii/ Journal, January, 1917 



905 



instance, the destruction of pines to 

 save the currants, or, vice versa, of 

 the currants to save the pines? These 

 would certainly be the most efficient 

 means to arrest this disease. The 

 next important lesson to be learned 

 from the life history is the modes of 

 spreading of the disease. It spreads 

 of its own accord on currants or 

 gooseberries, for miles in one season, 

 in all directions; and eventually 

 reaches a pine, a pine plantation, or 

 a forest, and these then, in turn, may 

 start new outbreaks. Hence the next 

 lesson to be learned is this: — no 

 currants or gooseberries near pines; 

 no pines near gooseberries or currants. 

 How far apart should these 

 different host plants grow from each 

 other? This point is still an open 

 question — but the farther apart the 

 better. Can this be carried out? 

 Sometimes a single pine, or a few 

 pines menace the cultivated currants; 

 sometimes a few shrubs of the latter, 

 the former. Therefore, whichever, 

 in a given locality, is the more im- 



portant must remain, and the other 

 be destroyed— certainly if affected, 

 but better at any rate. Most im- 

 portant of all, all wild currants and 

 gooseberries should be destroyed: 

 they are most serious offenders. This 

 should be done everywhere in or near 

 valuable pine woods. 



There is yet another danger, that 

 currant rust spores may adhere on 

 baskets of currants or other fruit, 

 when shipped from an infected area, 

 and spread the trouble very widely — 

 that the disease will eventually find 

 its way to a pine. So far as now 

 believed, currant bushes in themselves 

 and sold as such, do not appear to 

 carry the disease, once the leaves are 

 gone. Doubt still exists on this point, 

 which we are now endeavouring to 

 settle. Should the disease be con- 

 veyed by infected currant bushes, this 

 would constitute a new menace, and 

 the question become more difficult. 

 Ho^yever, it is generally held that in- 

 fection of currants occurs every year 

 afresh from nearby pines, strange as 

 this may seem. 



THE DISEASE IS CARRIED ON PINE NURSERY STOCK 



We know for certain that the pine 

 carries the disease — it was by pine 

 seedlings from Europe that the 

 disease was introduced; hence im- 

 porting pines into Canada should be 



stopped. This was done shortly after 

 taking up my work in Canada. 

 No pines (five-leaved) can enter 

 Canada from anywhere abroad, reads 

 an order-in-council. 



QUARANTINE AND CONTROL MEASURES NECESSARY 



A federal quarantine against white 

 pine seedfings or other five leaved 

 pines, and, if possible, against cur- 

 rants, etc., from infected provinces or 

 areas, or individual nurseries, is desir- 

 able. The first work to do is the accu- 

 rate location of every infected locality 

 — this requires men and time, the more 

 men the shorter time. The shorter 

 the time it takes to know accurately 

 the distribution, the better the chance 

 to fight this disease. Therefore, let 

 all concerned come to the fore! The 



question is of greatest moment; and 

 the experiences of other countries 

 are on record. Shall we too fail, 

 where others have also failed? It 

 may become necessary, but not until 

 the distribution in Canada of the 

 disease is fully ascertained, to es- 

 tablish a safety belt of considerable 

 breadth in which currants and pines 

 shall be wholly eradicated, isolating, 

 if possible, the infected area from 

 valuable timber limits. Wherever 

 diseased pines are located they should 

 be immediately destroyed. 



