GREENHOUSE MANAGEMENT 429 



essential in the garden out of doors it is doubly necessary in the 

 garden under glass. Not a few of the pests that are active out- 

 side are equally destructive indoors, and the remedies recommended 

 in a previous chapter may be employed with just as satisfactory 

 results in the greenhouse as in the open. But the owner of a 

 greenhouse has this advantage in fighting the pests that attack 

 his plants, that he can vaporise or fumigate his glass structure and 

 in this way check or destroy many insects which the outdoor 

 gardener is only able to exterminate by syringing. For fumigat- 

 ing or vaporising there are several well-tried and effective pre- 

 parations that can be obtained from the florist. The basis of 

 them all is usually nicotine in one form or another, and if it be 

 properly used its effects on the insects it is designed to exterminate 

 are disastrous, while no harm is done to the plants. 



The best time for fumigating is the evening of a calm day, 

 since by choosing this time it is possible to keep the house closed 

 until the morning, and thus a sufficient period will be allowed 

 in which the fumes can perform their deadly work. All ventilators 

 must be closed tight and all holes be stopped up so that none of the 

 fumes can escape. For aphides or greenfly one fumigation will 

 be found enough, for thrips two may be necessary, and for red 

 spider three. These should be on consecutive days. 



Among the commonest insect pests with which the owner of a 

 greenhouse will have to contend are aphides, mealy bug, red 

 spider, scale and thrips. 



For aphides the usual remedy quassia and soft soap solution 

 may be applied, while an excellent preventive is an occasional 

 syringing with clear soot water. 



Mealy bug can be checked by washing the leaves and stems 

 of plants with an emulsion composed of one pound of soft soap 

 and half a pint of paraffin dissolved in ten gallons of water. 



Red spider can be kept at bay by maintaining a moist atmo- 

 sphere in the house. Frequent syringing will be found beneficial. 

 Where the pest has obtained a foothold the loaves should be 

 sponged with soft soap and water, and the hot-water pipes be 

 iprinkled with flowers of sulphur, 



