442 



HARDY FRUIT GARDEN. 



The natural enemy to this insect is stated by Mr 

 Westwood, in "The Gardeners' Chronicle, 1849," 

 p. 60, to be a very minute hymenopterous 

 parasite, belonging to the genus Encyrtus, which 

 breed in such vast numbers in the body of a 

 single caterpillar, that its skin, instead of shrivel- 

 ling up, is distended and dried so as to retain 

 its proper form. He also suggests, as a mode of 

 destroying the perfect insect, to attack them as 

 soon as they have made their appearance, and 

 before they have deposited their eggs. " The 

 general simultaneous appearance of the whole 

 brood in the winged state, together with the 

 very conspicuous appearance of the moths, will 

 render this easy. A sheet may be laid beneath 

 the branches in the daytime, which should then 

 be sharply struck with a stick, when the moths, 

 which are at that time sluggish, will fall into the 

 sheet, and may be easily destroyed. The de- 

 struction of one moth thus prevents the injuries 

 which would otherwise arise from one, if not 

 several, colonies of caterpillars in the following 

 season." 



The apple-bark beetle {Bostrichus dispar Autor, 

 Apate dispar Fabricius, Xyloterus dispar Erich- 

 son). This is one of a tribe often called borers, 

 on account of their boring into the trunks and 

 branches of fruit trees. Our present subject 

 seems to prefer the apple to all other trees, but, 

 fortunately, it is not very abundant in .Britain ; 

 neither is it of yearly appearance, some years 

 appearing, and for several others scarcely seen. 

 The female beetles have the head and thorax 

 black ; the male is chestnut brown, with reddish 

 thighs ; the points of the antennae and palpi 

 reddish in both ; the cases of the wings long, 

 blackish, and slightly hairy ; thighs black ; feet 

 reddish yellow. The female is about as large 

 again as the male, and also of different form 

 (from thence the name dispar, or unlike). They 

 seldom lay their eggs near the ground, or on 

 trees of less than \ inch in diameter, preferring 

 the principal stem or larger branches of esta- 

 blished trees. When the female has selected a 

 place to her mind, she begins boring through the 

 bark and wood in a somewhat oblique direction, 

 often till she reaches nearly the centre of the 

 stem or branch, but more generally in the albur- 

 num or young wood. These perforations are 

 not in direct lines, but often very crooked, and 

 branching off in different directions, forming 

 various chambers in which the young are reared. 

 The presence of the insect within a tree is 

 readily detected either by the exudation of the 

 sap at the openings of the perforations, or by 

 the appearance of minute particles of wood, 

 somewhat like fine meal, pushed outside the 

 entrance of the hole. For the reception of 

 her eggs the female makes the mouth of the 

 hole considerably wider than it is within. In 

 this she lays her eggs to the number of from 

 seven to ten at a time, and may lay from thirty 

 to forty in all during the season, of a pure white 

 colour, somewhat pointed at the ends. The first 

 brood of larva? is hatched about the end of 

 May, and they appear to remain enclosed in 

 their wooden chambers almost immovable until 

 they have assumed the perfect beetle state. 

 They are very destructive to the apple in Ame- 



rica and the north of Germany, in which latter 

 country the general remedy has been to cut off 

 the branches infested by them ; and if the whole 

 tree is attacked, to cut it down, and remove it 

 from the garden. We have little doubt that 

 spirits of tar applied to the stems and larger 

 branches would be found a complete remedy, 

 acting both by destroying the larvse, and also 

 by deterring the female from boring into the 

 tree, on account of the offensive smell of the 

 tar. 



The apple chermes, fig. 189 (Chermes mali 

 Schmidt, Psylla mali of others), resembles con- 



Fig. 189. 



Perfect and preparatory state. 



siderably the Chermes pyri in size and appear- 

 ance, on account of which it has been by some 

 thought identical. The former differs greatly in 

 its economy from the latter. Chermes mali pair 

 and lay their eggs in September, whereas C. 

 pyri do so early in spring. The eggs are said 

 by Kollar to be " perfectly formed in the body 

 of the mother before pairing takes place, as is 

 the case with Aphis mali (the apple aphis). 

 Before they pair, five or six of them assemble on 

 an apple leaf, and indeed usually on one that 

 has become somewhat yellow, and each male 

 selects his female. The males are either of a 

 lively green, striped on the back with yellow, 

 a dark yellow with brown stripes, or almost 

 completely green, with dark-yellow dots ; the 

 abdomen is entirely yellow. The females are of 

 a prettier colour, and somewhat larger ; the 

 entire back, reaching as far down as the forceps, 

 at the extremity of the abdomen, is red, striped 

 with greenish yellow and brown, and the abdo- 

 men is orange-yellow and green ; they are green 

 or greenish yellow on other occasions." The 

 eggs are laid on the twigs of the trees both of 

 the current and last year's growth, and fre- 

 quently in the knots and about the base of the 



