168 Commercial Gardening 



expect any assistance from birds of the air to lessen their numbers, as 

 a bird in a plant house is literally a rara avis, and is too frightened and 

 flustered to search for the grubs or eggs of obnoxious insects. The grower 

 of crops under glass must therefore rely upon other remedies. Besides 

 using solutions made from nicotine, quassia chips, soft soap, arsenic, &c., 

 on the plants themselves as preventives, the grower would be wise to 

 cleanse his houses thoroughly after they have been cleared of the crops. 

 The walls should be covered with hot limewash, and the woodwork should 

 be painted at least once a year, but more frequently if possible; and if 

 some paraffin and cement be churned up in the limewash, a thin covering 

 will be applied to the walls that will seal up effectually the eggs of any 

 pests that may be hidden in the crevices. In addition to this, sulphur 

 or brimstone should always be burnt in an empty house before a fresh 

 crop of plants is brought in. A strong sulphur vapour is not only fatal 

 to insect pests but also to fungoid diseases. By this means such stove 

 and greenhouse pests as scale, mealy-bug, red spider, thrips, slugs, snails, 

 wood-lice, ants, &c., may be reduced almost to vanishing point. The 

 keynote to immunity from pests in the greenhouse is cleanliness, not 

 only of the structures themselves, but also in the methods of cultivation. 

 A certain expense will be incurred, but it is better to spend it in this 

 way than in trying to secure freedom from attack by artificial means. 



Fumigating. Besides keeping the walls and woodwork of glasshouses 

 clean with limewash, paint, &c., it is more or less essential at times to fill 

 the atmosphere with fumes that are deadly to pests that may be actually 

 feeding upon the crops, or are likely to become a nuisance in that way. 

 In former days the only method of cleansing a glass structure was by 

 applying tobacco smoke in some way or another. If the genuine tobacco 

 could not be afforded, rags and paper steeped in tobacco juice were utilized 

 as substitutes. The tobacco, rags, or paper were placed in flower pots, 

 or old saucepans, buckets, &c., with holes in them, on a few live coals in 

 the bottom. The fumigating mixture was damped, but not sodden, with 

 water, to prevent the flaring of the material, which would have been 

 injurious to the plants in that state. By means of bellows the fire was 

 kept alight, and as the moistened tobacco, paper, or rags were consumed, 

 dense volumes of smoke filled the atmosphere, and while it destroyed the 

 pests, if sufficiently powerful, also upset the operator in many instances. 

 Great improvements have taken place in fumigating greenhouses of late 

 years, and fumigating cones of various descriptions are now in use that 

 will fill the house with fumes after being lighted, and will not necessi- 

 tate the close attention of the gardener. 



Vaporizing. Nicotine in some concentrated form has always formed 

 the staple fumigating material. It is now to be had concentrated in cake 

 or liquid form, and, although apparently expensive, is really very effective. 

 The cakes or liquid is placed in a shallow metal dish seated on a metal 

 stand. A small methylated-spirit lamp is placed beneath, and when lighted 

 dissolves the cakes or liquid into fumes that are diffused throughout the 



