36 



The Tortrices are a large group of rather small species, and some 

 few of them, either by reason of their vast numbers, or their methods 

 of feeding, are very real orchard or forestry pests. Even the most 

 casual observer must have noticed, that in some years towards the 

 end of May, when the oak trees ought to be in their full leaf, they 

 are, over great tracts of country, as bare as in mid-winter. This is 

 the work of the larvae of Tortrix viiidana, L., sometimes ably 

 assisted by the winter moths to which we have already referred. The 

 brilliant little green moths fly about the oaks in June and .July, and 

 deposit their eggs in crevices of the stem and branches, where they 

 remain until the following spring. Just as the leaf buds are begin- 

 ning to expand, the tiny larva comes outof the egg and wanders along 

 the branches and twigs until it finds a bud that is just expanding:, 

 in which it secretes itself and commences to feed. By the middle 

 of May it has changed its skin for the third time and the leaves are 

 fairly well opened. It now turns down the edge of one side of a 

 leaf, and secures it by a few silken threads, thus making for itself a 

 secure dwelling. Then it feeds rapidly, eating the other side of the 

 leaf in which it dwells and those in its neighbourhood, and thus the 

 devastation takes place.*"' The denudation of the trees of their leaves 

 cripples their vitality, and if the attack is repeated for several years 

 in succession may even lead to their death. T know of some trees 

 in Tiigate Forest, where the attack has been very severe for several 

 years past, that have been killed outright, the pi'ime cav;se of their 

 death evidently being the continued attentions of these larvae. 



It will be evident that to deal with so vast an attack by artificial 

 means would be a hopeless task, but fortunately Nature comes to our 

 aid. Birds are very fond of these larvae and pupae and devour 

 huge numbers of them. Even the much abused jay [Garritlus 

 (jlandarius) is not averse to them, as is shown by some three dozen 

 of the pupae being taken from the crop of one of them. A Hemip- 

 teron (bug) sucks the juices of the young larvae and thus destroys 

 them, and they are also attacked by a considerable number of species 

 of ichneumonid and other hymenopterous parasites (see "Ent. Mo. 

 Mag.," 1922, page 56). Very wet weather just at a critical time is 

 an even greater check to them. 



A nearly allied species, Tortrix proniibana, was unknown in this 

 country until 1905. In the following year larvae were found 

 in some numbers on the south coast, and the species has since that 

 time become more and more common and spread inland, and is now 

 causing considerable trouble in some of the houses in Kew Gardens. 

 In the Channel Islands, where it has been established for a much 

 longer time, it has been known to cause damage in the grape 

 houses, and it will be well that our market gardeners, especially 



« Sich, " Proc. South London Ent. and Nat. Hist. Soc," 1915-16, p. 15. 



