The devices and implements used for fighting plant enemies are of two sorts:
(1) those used to afford mechanical protection to the plants;
(2) those used to apply insecticides and fungicides.
Of the first the most useful is the covered frame. It consists usually of a wooden box, some eighteen inches to two feet square and about eight high, covered with glass, protecting cloth, mosquito netting or mosquito wire. The first two coverings have, of course, the additional advantage of retaining heat and protecting from cold, making it possible by their use to plant earlier than is otherwise safe. They are used extensively in getting an extra early and safe start with cucumbers, melons and the other vine vegetables.
Simpler devices for protecting newly-set plants, such as tomatoes or cabbage, from the cut-worm, are stiff, tin, cardboard or tar paper collars, which are made several inches high and large enough to be put around the stem and penetrate an inch or so into the soil.
For applying poison powders, the home gardener should supply himself with a powder gun. If one must be restricted to a single implement, however, it will be best to get one...