Domestic Encyclopædia (1802)/Supplement/Spider, the Red

SPIDER, the Red.—Independently of the method of exterminating these vermin, already suggested, the following is recommended by Mr. Forsyth. It merely consists in irrigating the infested plants with lime-water, in the afternoon, particularly on the lower sids of the leaves. In hot-houses, however, he advises a barrow-engine to be filled with soft water, and all the plants to be sprinkled, by directing the stream against the top-lights, and shelves, till the water be an inch deep in the paths. But, where the building will not admit of the entrance of a barrow-engine, the front or top-lights must be slidden down, and the water poured in, from above. When this affusion is commenced, if in the inside, every light ought to be shut; but, if the fluid be introduced from without, one light only should be opened at a time; and which must be shut, as soon as the part opposite to it is sufficiently watered. The other lights are then to be successively removed; and, when the irrigation is completed, the house should be carefully closed till the next morning. In consequence of this operation, vapours will arise in every part of the building; cover all the plants; and effectually destroy the red spider, together with all other vermin. Mr. F. farther observes, that the watering must be repeated every day, during hot weather; and that it will, in general, shorten the labour, which would otherwise be required in irrigating plants. Such vegetables, however, as require copious humidity, ought to be watered previously to sprinkling the house: thus, the plants will imbibe all the moisture, and the paths will become perfectly dry, during the night.