286 ENGLISH ESTATE FORESTRY 



contemplated with resignation, as nothing can be done on 

 a large scale to prevent the attack, or remedy it after it 

 has commenced. In good growing seasons it is not par- 

 ticularly conspicuous, owing to the more rapid growth of 

 the shoots, and the aphides being spread over a wider area. 

 But in dry summers, or cold blighting Mays, the slow growth 

 of the trees reduces the area over which the multiplying 

 aphides are spread, and the trees gradually assume that 

 mealy appearance which is characteristic of a bad attack. 

 Eminent authorities have expressed the opinion that an 

 intimate connection exists between the larch aphis and the 

 larch disease, and that the presence of the former is respon- 

 sible for that of the latter. Plausible as this theory looks 

 on the face of it, we have not yet seen any direct evidence 

 adduced to prove any connection between them. It is an 

 obvious fact that larch badly infested cannot be perfectly 

 healthy, and that unthrifty larch is, in all probability, more 

 prone to disease, or suffers more from the effects of it, than 

 trees with a strong vigorous growth ; but this does not 

 necessarily prove that if the aphis were absent so would be 

 the disease. 



According to M'Intosh, the larch bug first appeared in 

 England in 1800, and was very prevalent in that and the 

 two following years, which were very dry. Pontey, in his 

 Forest Planter, states that it was very prevalent in the south- 

 west of Yorkshire, and that by 1808 it had almost dis- 

 appeared. His experience was that it was least injurious on 

 light sandy and calcareous soils. Whether it first appeared 

 or was first noticed in this year it is difficult to determine, 

 as until it assumed the character of a pest it would not be 

 likely to attract the notice of practical foresters. Since then, 

 however, it has certainly been more or less prevalent in pure 

 larch plantations, and has been most conspicuous in dry, hot 

 summers, which have been unfavourable to the healthy growth 

 of the tree. 



It is often observable that the attack of the aphis is 

 worse in some parts of a plantation than in others, whereas 

 its presence is more or less universal. This can only mean 

 that the less vigorous growth of the trees in such places 

 intensifies the injurious effects of their presence, and not 



