60 



JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



Here again good cultivation greatly tends to palliate the evil by 

 encouraging a healthy vigorous growth of the trees. Marie Louise 



CLADOSPORIUM ON APPLE 3. 



and Louise Bonne of Jersey pears are very subject to it, and 

 should not be planted in places infested with the disease. 



Rust on the pear is caused by Bcestelia cancellata, as well 

 as some other parasitic fungi. The Roestelia produces rugged 

 swellings on the leaves, the blotches finally becoming red, and 

 showing themselves on both surfaces of the leaves attacked. It 

 is believed to be an early stage of Gymnosporangium Sabince, 

 which completes its life cycle on Juniperus Sabina. As in the 

 rust of wheat, there is an alternation of generations on different 

 host plants, and described as hetersecism. It is not common in 

 England, is not, I believe, recorded from Scotland, but is very 

 destructive on the Continent. Hand-picking the leaves as the 

 spots make their appearance, and before the spores are shed, is 

 the only remedy, and no juniper bushes should be allowed to 

 grow near them. On a large scale it is more profitable to uproot 

 badly-affected specimens and plant afresh. 



Mistletoe in this country is the only chlorophyll-bearing 

 parasite that need be noticed. It is very injurious to orchards 

 in Herefordshire from its great prevalence, and prevents the 

 branches infested by it from thickening properly below the union 

 of the parasite with them, ultimately causing the trees to become 

 stunted and unproductive. Cut down the mistletoe about 

 Christmas, when a market will be found for it to defray the 

 expenses of the operation. 



Epiphytes, such as lichens and mosses, can be removed by 

 scraping or scrubbing the bark of the trees, or they may be 

 destroyed by sulphuric acid much diluted in water. The evil is 

 but half remedied, however, and the lichens will soon grow again 



