GRAPE-MOULD. 239 



by spores produced in black spore-cases during the second or third year. 

 The development of L. pinastri depends greatly on a damp condition of 

 the air ; and dry summers, cold winters, and dry spring weather check 

 its spread, while a moist summer, followed by an open t mild winter, 

 favour it. 



Remedy. Avoid use of Pine foliage in nurseries; pull up and burn 

 infected plants ; and spray annually in July and August or oftener with 

 Bordeaux mixture, 2 Ibs. sulphate of copper (bluestone, copper-vitriol) 

 dissolved in 10 gallons water, and 1 Ib. freshly-burned lime added, which 

 generally, though not always, checks the disease. 



* The Grape - mould, Botrytis cinerea, saprophytic on dead Conifer 

 foliage, but also spreading as a destructive parasite on all Pines, Firs, and 

 Larch in nurseries and natural regenerations, is the conidia - form of 

 Sclerotinia Fuckeliana, and often does serious damage in wet springs and 

 summers, especially to Douglas Fir, Silver Fir, and Spruce. If Conifer 

 sprays or foliage be used in nurseries there is always great danger of this 

 disease appearing first as a saprophyte, then becoming parasitic, when 

 the shoots of young plants attacked become twisted or bent, and the 

 leaves die off as if frosted, though often held together by the ashy-grey 

 cob web -like mycelium. Spores alighting on young leaves or shoots in 

 damp weather soon germinate and enter the tissue, the mycelium 

 penetrating intercellularly and killing the tissues. Sporophores and 

 sclerotia are formed, the spores remaining dormant and germinating with 

 favourable conditions. On germinating, the spore-tubes cannot pierce the 

 bark of a 2-year-old seedling, except at a wound-surface caused by late 

 frost, insects, &c., when the fungus destroys the cambium and kills the 

 plant. 



Remedy. Spray frequently with Violet Mixture, 2 Ibs. sulphate of 

 copper, 3 Ibs. carbonate of copper, 3 oz. permanganate of potash, \ Ib. 

 soft soap, and 18 gallons of rain-water (the soap being dissolved in hot 

 water), all the infected ground, and beyond it, being thoroughly wetted. 



More or less serious damage is also sometimes done by Rhizina undulata, a 

 saprophytic root-fungus, also parasitic on young Conifers on sandy soil, and 

 producing flesh-like, stalkless, velvety sporophores, chestnut brown above 

 and pale below, from 1 to 3 in. long on the roots, and by Rhizoctonia 

 violacea, the heather-fungus, which surrounds young Conifer-roots with 

 a close violet mycelium and produces black warty sporophores on the 

 dead roots. 



II. Chief Fungus Diseases in Plantations and Woods. 



* Lophodermium pinastri (see above) also attacks young Conifer 

 plantations, while L. macrosporum attacks the leaves of 2-year-old shoots 

 in Spruce plantations from 10 to 30 years of age, turning them rusty-red 



