io 4 THE BOOK OF FERN CULTURE 



soil. The best method of checking its progress is to 

 clean off the surface soil after plants have been fumigated. 

 Water the stages with strong insecticide or weed-killer. 

 Lime and sulphur in equal parts may be dusted into the 

 crowns of plants affected. 



The ordinary thrips may give trouble, and it is 

 remarkable that this is very partial to Ferns which pro- 

 perly belong to the cool house. 



Take the Cyrtomiums, Gleichenias, and some of the hardy 

 Pterises, when grown in warmth if there are any thrips 

 about they are sure to find the Ferns, and will soon 

 increase. It may be worthy of remark that with thrips 

 the eggs are laid and it takes a few days for them to 

 mature ; and when fumigating for thrips it is necessary it 

 should be done about three times successively, at intervals 

 of two days. The ordinary brown scale will often get 

 established, especially on Aspleniums, yet it only wants 

 care and perseverance to exterminate it. The great 

 mistake that is often made is that they are left until the 

 spawn is ripe, and when the old covers are removed it 

 lets loose myriads of small ones. One of the best 

 growers always isolated any new introductions until he 

 was quite sure that they were clean, and by this means 

 much labour was saved. Mealy Bug, when once it gets 

 established, is most difficult to eradicate. It will live 

 under the rims of the pots and in any crevice that it can 

 creep into, and remain until a favourable opportunity 

 occurs for it to establish on the plants. If this pest is 

 confined to a few plants it will be much cheaper to burn 

 them and replace with young, clean plants. Pots have 

 often conveyed Mealy Bug to what had previously been 

 clean plants,. and even with old soil some troublesome 

 insects may be introduced. 



In the out-door Fernery it is necessary to leave some 

 of the old fronds during the winter to protect the plants, 

 but where the temperature is kept above freezing-point 



