Reports to the Board of Agricitltnrc. 1 73 

 The Canker Caterpillar of the Oak. 



(^Tvrlric rirUlana.) 



The tevDi '• Cankia-" or " IMiglit" caterpillar is soiiietiuies used It.v 

 foresters and labourers when speaking of tlie (Ireeu Oak Tortrix 

 ( T'ortrix viridana). 



The Greeu Oak Tortrix occurs in great numbers some years, and 

 its ravages are often persistent, Listing, as in Windsor Forest, for 

 four years (1890-181)4). The moth that gives rise to this so-called 

 (Janker worm or Oak-leaf Holler is alx)ut four-lifths of an inch across 

 the expanded wings, liut varies in size ; the fore wings are uniformly 

 pale apple-green, with the costal edge sulphur coloured, the hind 

 wings whitish grey, and all the wings have white fringes. They 

 appear on the wing in June and July and fly during the day-time. 

 They lay their eggs singly or in groups on the buds and pass the 

 winter in this stage. The larvie hatch in April and ]\lay, and at 

 once commence to feed upon the buds and leafage. When mature 

 they are about three-tifths of an inch long, grey or greyish-green in 

 colour, yellowish-green posteriorly, with blackish-brown head, and 

 small black spots on the Ijack. They not only de\our leaf and 

 bud, but also the inflorescence. When full fed they roll a leaf up 

 and pupate inside the tube, usually in the early part of June; the 

 pupa is two-fifths of an inch long, black in colour. The pupie are 

 also found in crevices in the bark. A habit very noticeable in tla' 

 caterpillars is that of lowering themselves from the leaves by threads 

 of silk, and by means of these silken cords they regain the foliage. 



Small trees in parks and gardens can be cleared by arsenical 

 washing. No remedies can be applied in forests. The great thing 

 is to protect natural enemies, namely, rooks, jackdaws and starlings, 

 Mhich feed upon the caterpillars ; tits devour the eggs. 



'Ilie caterpillars of the Dunbar Moth (OoHiiiuf frupc-jiua) feed 

 upon this grub. 



Besides oak, hornbeam is also attacked by T. vlrldanK. 



