Control of both these flies depends upon the destruction of infested bulbs. Recent researches have shown that the flies themselves can be poisoned in large numbers by a spray made of 4oz. of sodium arsenate, 1lb. of crude glycerine, 2lb. of white sugar, and four gallons of water; this spray is applied during bright and warm weather.
Springtails.—These are very minute, soft-bodied insects, which are very active, and have a habit of springing with the agility of fleas. There are several species, but two are of interest to the horticulturist.
One of these ([Fig. 12], k1) is white in colour, narrow-bodied, and lives underground, especially in damp places, where it damages germinating seeds, or the roots of seedlings; even older herbaceous garden plants are attacked. As a control, it is important to drain the soil in damp locations and to dig in calcium cyanide about two weeks before planting or sowing.
The second species is blackish and more or less spherical ([Fig. 12], k2); at times it does considerable damage in the spring to the seed-leaves of young plants as soon as they appear above ground. Spraying small areas—e.g., of cucumbers, turnips, etc.—with black-leaf 40 would help to protect the plants; as the eggs are laid in the ground, and as these develop best under moist conditions, thorough cultivation prior to sowing the crop is an important controlling factor.