GENERAL SUMMARY 191 



special attention should be given to the survey of recently 

 felled areas, as in such situations infected localities can be 

 more exactly determined, and may be dealt with more 

 successfully. Lastly, where fructifications are abundant, it 

 is worth while to cut them down with a scythe or sickle, 

 as once they are cut through they have little chance of 

 spreading their spores. 



About needle diseases the predispositionist can have 

 little to say, since there is no reason to believe that the 

 needles borne by robust trees are in any way less liable to 

 attack than their weaker fellows. The only needle disease 

 which need be seriously feared, outside the nursery, is the 

 needle-cast, Sphaerella laricina, which may become epidemic, 

 especially where larch is mixed with spruce or other ever- 

 green. Where such mixed woods are attacked by this 

 disease for many years in succession it is worth while to 

 thin them out and to remove one or other species entirely. 

 If it is decided to keep the larch, underplanting with beech 

 is calculated still further to lessen the damage inflicted by 

 the disease. 



The fungi that attack nursery lines of larch are chiefly 

 rusts and the damping-off fungi. Rusts may be prevented 

 if it is possible to remove the alternative hosts. Damping-off 

 should be met first of all by good cultivation of the soil, 

 and secondly by spraying or powdering as recommended in 

 the section on these pests. 



The long list of diseases to which the larch is liable must 

 produce a depressing eft'ect, especially when set out in 

 a single story, as in this book. Many of these diseases are 

 unimportant, and many are shared by other conifers which, 

 in addition, present pathological difficulties unknown to the 

 larch. None the less, the larch is more prone to disease 

 than any other conifer commonly grown in British woods, 

 and the advisability of planting other trees in the place of 

 larch has been carefully considered by most foresters. The 

 variety of trees introduced from Western America has 

 added greatly to the list of species at the planter's disposal, 

 and Douglas fir and Sitka spruce have already been widely 



