TAB. 339 



Use against Fungi. — SphcErotheca paiinosa, Wallr. (mildew of the 

 rose). — Del Querela and Baroni found that rose mildew was destroyed 

 by coal-tar bouillies. They advise for this purpose to spray before 

 flowering with a bouillie consisting of 1^ lb. of carbonate of soda and 

 ■^ lb. coal tar in 10 gallons of water. The bouillie injures the colour of 

 the roses because it is alkaline. Martini prefers a bouillie consisting 

 of wood tar dissolved in soda lye 14 lb., blue vitriol 1 lb., quicklime 

 1 lb., in 10 gallons of water. 



Ananas (cane-sugar disease). — This fungus is propagated chiefly 

 by the cuttings. By coating the sections with carbolized tar, Went 

 overcame this disease, preventively, better than by cupric bouillie. 



Nectria ditissima, Tul. (canker of the pear-tree and apple-tree). — 

 The cankers of fruit trees, whether caused by the woolly aphis or by 

 the nectria fungus, are overcome and cured when the tree is not too 

 much infested by completely excising them, and covering the wounds 

 by a mixture of wood tar and pulverized wood charcoal, or by a mix- 

 ture of 1 part of coal tar and 4 parts of pulverized slate, or even 

 by a thin layer of hot tar. The tar prevents contact with the air, kills 

 the germs of cryptogamic disease, and stimulates the growth of the cells 

 of the epidermis so that cicatrization is accelerated and large decorti- 

 cated surfaces become covered with healthy bark in the course of the 

 year. 



Rot of Cuttings. — It has been found that tarring the ends of cuttings 

 prevents their rotting in the soil. This effect is especially noticeable 

 when bouillie bordelaise is combined with the tar by dipping the end 

 to be buried first into the bouillie and then into the tar. 



Pohjporus igniarius, Fries (false tinder). — To prevent its ravages 

 care must be taken to cover with a layer of tepid tar all the wounds 

 produced on trees by lopping, hail, the sun, woolly aphis. If the hoods 

 of the polyporus show on a branch, this spot must be deeply excised 

 to destroy the greater part of the mycelium, and the whole covered 

 with tar. Hollow trees may be filled with sawdust impregnated with 

 wood tar, and the openings plugged with clay or mastic. That pre- 

 vents the internal decomposition from pursuing its course, for the 

 fungus must have contact with air for its development. 



Slugs. — The ring of coal tar, |-f inch wide, is quite sufficient to 

 prevent snails and slugs from crawling along the trunks of trees and to 

 avoid their ravages (Pastre). 



Use on Insects. — Melnlontha vulgaris, L. (cockchafer). — Eaze- 

 burg remarked in 1847 that the cockchafer had a great repulsion for 

 tar. He recommended to protect plants against their attacks to bury 

 in the hole, dug for planting, a rag steeped in tar. Weny found that 

 Balbiaiai's mixture, consisting of tar, naphthalene, and lime, eradicates 

 the white-worm of the vine, and Landisch points out that it suffices to 

 insert, at certain intervals, and at a depth of 10 inches, pegs dipped in 

 tar to protect a crop threatened by the white-worm. 



Valgus hemipterus. — A small aitonia, the larvae of which rapidly 

 destroy the props and posts of enclosui-es, by nibbling the underground 

 part even when tarred. To preserve them, they must be treated thus : 

 The props and posts are coated in the underground portion with a 



