GEOMETERS. 



107 



corresponding to the three stages of the 

 enemy's existence caterpillar, chrysalis, 

 and nioth. 



1. When the caterpillar is still in the 

 buds it must be left to the bullfinches and 

 titmice, as human exertions fail to effect 

 any considerable diminution of its numbers 

 It is not, however, to be supposed that 

 bullfinches only pick off those buds which 

 are infested with these caterpillars : the 

 contrary is most assuredly the case, and a 

 little company of these pretty birds they 

 travel in little companies of four, five, or 

 six will not unfrequently settle in a 

 gooseberry-bush, or plum-tree, and not 

 leave it until half the buds have been 

 picked off. It is a remarkable fact, and 

 one that I have repeatedly verified, that 

 scarcely half of the buds thus destroyed 

 are eaten ; the remainder may be observed 

 scattered on the ground beneath. When 

 the caterpillars have emerged from the bud, 

 fed for some fortnight or three weeks, and 

 are nearly full-grown, shaking or striking 

 the trees with a stick will cause them to fall 

 to the ground, or to hang by a thread. 

 When on the ground they can be crushed 

 under foot, or caught in cloths and burned. 

 Before shaking the tree some persons daub 

 the stem near the ground with a sticky 

 mixture, or pour coal-tar on the ground 

 round the stem, to cut off their escape as 

 they retreat : a good plan where the trees 

 stand alone, I ut of little service where there 

 is an undergrowth of gooseberry or currant 

 bushes, as the caterpillars will ascend them. 



2. Little can be done against the insect 

 in its chrysalis state. Digging the ground 

 under the trees in August has theoretical 

 advantages : it displaces the chrysalis from 

 ,ts self-selected habitation, and subjects it 

 to the cha::ce of more or less moisture than 

 is congenial to its nature : and breaking up 

 the soil exposes it to the attacks of beetles, 

 earwigs, and bii ds, all of which feed upon 

 it. Several years' experience has failed to 

 show much practical benefit from the pro- 

 cess. It can only be recommended as 

 auxiliary to other means of destruction. 



3 The third campaign is the most impor- 

 tant, The female moth, having no wings, 

 is compelled to climb the tree to deposit her 



eggs, and may be caught by a sticky com- 

 position placed in her path. 



In Germany this is done by surrounding 

 the stem with a four-sided box about twelve 

 inches high, the lower end of which is fixed 

 in the ground, and the upper end coped. 

 Tar daubed every few days on the outside 

 of the box, below the coping, catches the 

 females in their ascent. This box plan was 

 found to be expensive for thickly-planted 

 orchards, so it became important to get a 

 composition which might be applied directly 

 to the stem without injury to the tree. 

 Various things were tried, of which Stock- 

 holm tar and cart-grease mixed in equal 

 proportions proved to be the best. This 

 compound remains sticky four or five days, 

 and the experience of eight years shows 

 that it does no material injury to the trees 

 if applied in November and December, the 

 period when the moth is out ; but applied 

 in the warm weather of April and May it 

 has proved destructive in many cases, prob- 

 ably from its greater fluidity in the latter 

 case, allowing the tree to absorb it prior to 

 drying. 



The composition rather tightens the 

 bark, which should therefore be slit the 

 next summer, but in other respects does no 

 injury that can be perceived, even when 

 trees are cut down and split open ; and the 

 growing bark sliced off with a knife is the 

 same colour where the daub is applied as in 

 other parts. It may be employed without 

 fear, but where fear does exist, a coat of 

 whitewash made of whitening and glue size 

 applied before the daub will afford addi- 

 tional safety, as thick grease will not pene- 

 trate glue. 



From the 20th October to the 20th of 

 December, the gardener should examine his 

 plantation every evening with candle and 

 lantern, and destroy by hand all the moths 

 within reach. The couples are mostly on 

 the stem or within reach, and very visible. 

 If he find the moths numerous and some- 

 times they are (the men say) as thick as 

 bees he should the following day daub his 

 trees with a ring of this composition round 

 the stem or branches in the most conveni- 

 ent places, taking care to leave no other 

 path to the tree, such as side shoots, or 



