INSECT PESTS OF FERNS. 



5 



large plants of robust species may have their balls of soil and roots considerably reduced, 

 or combed out with the aid of a stout pointed stick, afterwards trimming them with a 

 knife, and they can then be returned to pots of nearly or quite the same size they were 

 in before. All do not need re-potting every season, but can be kept growing strongly 

 with the aid of abundance of water and weak liquid manure. Nor do any of them require 

 very large pots. They are most effective in pots small in proportion to the size of the 

 plants, while, if over-potted, the new soil is liable to become sour and injurious to the 



Fig. 98. POLYPODITTM SCHNEIDERI. 



roots, the plants quickly assuming a sickly appearance. In every case clean, well-drained 

 pots or pans should be used by way of safeguards against souring of the soil. Fine speci- 

 mens are then soon established, after the manner of the beautiful Polypodium Schneideri 

 (Pig. 98). 



Insect Pests.— Ferns are liable to be infested and injured by all the insect pests to 

 which stove plants generally are liable. Thrips are, or were at one time, most to be 

 feared, but thanks to the introduction of nicotine vaporizers, they can now be destroyed 



