408 FOREST ENTOMOLOGY. 



pine to be subjected to attacks of Hyluryus piniperda. Again, the 

 site ought to be considered as regards shelter, for while it is obvious 

 that too much shelter is not advisable for subsequent planting in the 

 open, still it is much better to err on the side of shelter, and then 

 never plant out before young growth is fully matured, as, on the other 

 hand, too much exposure results in an absence of constitution and 

 vigour ; hence growth is often not in proportion to anticipations, and 

 insects have an advantage. 



Again, it is possible that selection of seed is a point more important 

 than hitherto considered. It is perhaps true,'as many scientists have 

 asserted, that the vegetable organism, unlike the animal, does not 

 " hand on " the disease of the parent. Still, there is in all probabil- 

 ity an inherent weakness from the parent, and therefore a natural 

 predisposition to disease, — another point in favour of the insect. 



So far as the actual management of the nursery is concerned, too 

 many details cannot be given, as such would simply be an epitome of 

 nursery management. Great care should be taken as regards good 

 handling, as the very first thing to be considered is a good root on 

 the plant, and careful lifting of the stock ; and as regards the trans- 

 planting of seedlings and young trees generally, it is in most cases 

 essential to transplant or sell out always following two years' trans- 

 plantings. 



Much may be done to maintain a good constitution in young trees, 

 as prevention against insect attacks by transplanting at the proper 

 age. Take, for example, beech seedlings. If they are transplanted 

 at two years of age, they grow strong and healthy without any insect 

 attack ; but if they are transplanted when only one year old, they are 

 often injured by the woolly aphis {Pliyllaphis fagi). On the other 

 hand, ash seedlings are less liable to injuries from the tiny moth, 

 Prays curtisellus, when transplanted at one year old and left for two 

 years in the nursery-line, than when transplanted at two years old 

 and left two years in the nursery-line : besides, the former make the 

 better plants. 



The question of cleaning in summer has to some extent a beneficial 

 influence, both as regards the stimulating of the growth and the keep- 

 ing down of the weeds. ^ As regards the latter, it may be said that 

 weeds not only choke young plants, and therefore weaken them, but 

 it is possible that some species of green-fly may be assisted by weeds. 

 ' Tlie continual use of the dutch-hoe is a great stimulus to plant growth. 



