No matter in what form these insecticides are applied, the operation must be done thoroughly or little benefit will result. The contact sprays should be applied with force in such a way that every insect is covered. To apply the stomach poisons a fine, mist-like spray should be used which will coat the leaves with a thin film of poison. If too much is applied there is a tendency for the mixture to run into globules, which concentrates the poison at the tip of the leaves. This may result in injury to the plants and is not effective in coating the whole of the leaves. The feeding habits of some insects make it almost impossible to control them by spraying; so traps, poison bait, hand picking, repellents, or screening the plants to prevent access of insects are resorted to. These measures are fully described in connection with the insects against which they are used. Following are some of the more important insect pests. Beets.—_Flea-beetles_ (small, very active insects, as indicated by their name), _blister-beetles_, and various caterpillars, which eat the leaves, attack beets. Lead arsenate[4] should be applied as soon as the injury is noticed. ----- [4] Various spray formulas will be found at end of chapter. Cabbage.—Probably the worst insect pest of this crop is the _cabbage-worm_, a green caterpillar which hatches from eggs laid on the leaves by the common white butterflies, which may be seen flitting about the garden from early spring until fall. Spraying the plants with arsenate of lead to which a “sticker” has been added to make it adhere to the leaves is a standard remedy. Cabbage is also attacked by flea-beetles and caterpillars of various kinds, which are controlled by the same methods adopted for the cabbage-worm. Cauliflower.—Same pests as cabbage. Corn.—The _corn earworm_ is one of the worst of the pests attacking corn. This is a caterpillar which at first feeds on the “silk” and later penetrates the ear and eats the kernels. It is very difficult to control this insect. Lead arsenate sprayed or dusted on the silk as soon as it appears is a partial remedy. Cucumber.—The _striped cucumber-beetle_ is about a fourth of an inch in length, yellow in color, with three black stripes on the wing covers. It eats the leaves of the young plants and if unchecked ruins the chances of obtaining a crop. One of the best ways of dealing with this insect is to prevent it from gaining access to the plants by the use of cheese-cloth or wire mosquito-netting screens. These can be made by tacking the material used over bottomless boxes, not so high as to shade the plants, but of sufficient width and length to give them room to grow. Another method is to place two or three short sticks in the center of the hill and over these spread a “tent” of cheese-cloth, holding down the edges with stones and earth. Tobacco dust sprinkled plentifully over and around the plants acts as a repellent.