[ DISEASES OF CITRUS TREES 



although its presence may mean that there is too much 

 stagnant moisture in the soil around the tree. 



Colletotrichium gleosporioides, Penz., and Phyllos- 

 ticta citricola, Sacc., are two fungi found more or less 

 frequently on the leaves of Citrus trees. A severe attack 

 of Phyllosticta towards the close of summer may deprive 

 an orange-tree of most of its foliage, but this is a rare 

 occurrence and both diseases are easily kept in check by 

 inducing vigorous growth through proper tillage and 

 well regulated irrigation. 



Many species of Lichens, belonging to the genera 

 Rinodina, Roccella, Dirina, Caloplaca, Xanthoria, 

 Physcia, etc. are commonly found growing on Citrus 

 trees, and may impair their health by preventing 

 the trunk and branches from getting their due share 

 of air and light. Certain species, such as (Ramaiina 

 Duriei, Bag!) may be directly injurious, their rhizoids 

 penetrating into the bark and feeding upon it. Trunks 

 and branches thickly covered with these lichens show 

 distinct signs of impaired health. No new shoots are 

 formed, and the branch finally dies, and the lichens 

 continue to flourish, feeding on the dead bark and 

 wood. 



Various methods have been tried to get rid of the 

 lichens, all of which consist in applying a highly alcaline 

 watery solution over the bark infested with them. The 

 alcalies kill the lichens and set free the bark. Lime 

 wash is a good remedy, always at hand, but it has the 

 disadvantage of imparting a ghastly appearance to the 

 trees. Lime water either used alone, or mixed with an 

 equal quantity of ash-lye and applied over the bark with 

 a common brush will be found to give good results. Ash- 

 lye prepared from wood-ashes fresh from the fire, if the 

 solution is too strong, may cause injury to the bark, 

 especially in young trees. When treated with alcali the 

 lichens are killed and become very brittle, assuming a 

 reddish brown colour. They may then be rubbed off with 



