_White-fly._--The minute white-flies are common on greenhouse plants and

often in summer on plants about gardens near greenhouses. The nymphs are small greenish, scale-like insects found on the under side of the leaves; the adults are minute, white, mealy-winged flies. Spray with kerosene emulsion or whale-oil soap; or if infesting cucumbers or tomatoes, fumigate over night with hydrocyanic acid gas, using 1 oz. of potassium cyanide to each 1000 cu. ft. of space. (See page 188.)