122 DISEASES OF TREES 



in various parts of Germany, the enemy was left behind in its 

 native habitat, and the trees flourished to perfection. Prob- 

 ably every old forester knows some groups of larches of the 

 most stately growth which date back to that period. In conse- 

 quence of these satisfactory results, the larch was generally 

 planted throughout the whole of Germany. Most excellent 

 results were obtained, even where the inferior quality of the soil 

 held out but a poor prospect of success. 



But after woods of all sizes had been established from the foot 

 of the Alps to the coasts of the North Sea and Baltic, the fungus 

 spread downwards from the Alps, to find everywhere the most 

 favourable conditions for its development. These consisted of 

 dense young pure woods, groups that had been formed in re- 

 planting up old beech woods, moist stagnant air, wounds caused 

 by the moth, &c. Commerce also assisted to intensify the evil, 

 diseased larches being sent out from the nurseries and trans- 

 ported from district to district. 



Under these conditions the fructifications of the fungus 

 attained to luxuriant development and ripened their spores on 

 the blisters, while the spores found ample opportunity of germin- 

 ating, and of infecting the trees in the close pure woods. To-day 

 but few of the many promising young woods remain. The 

 larches have maintained their ground best in those woods 

 where a few were introduced as advance-growth. The air 

 circulating in the freely developed crowns has not only kept 

 the disease in check, but has also prevented the spores from 

 ripening on diseased specimens. 



Supposing that we have to do with a diseased larch wood, it 

 is first necessary to determine whether the damage is entirely 

 due to the moth or whether it is a case of fungoid blister. 



Often enough both will appear in company. If it is simply 

 a case of stunting in consequence of the attack of the moth, 

 pruning away the branches till only the vigorous upper part 

 of the crown remains may be permanently beneficial. The 

 upper branches will grow vigorously, and may form a good, 

 permanently healthy crown, especially as the moth is most 

 destructive on the lower branches. 



If it is a case of fungoid injury, pruning may assist somewhat 

 only if the bole as a whole, and especially the part in the crown, 



