Nature usually keeps insects in line with birds and other predators but sometimes certain creatures get out of control. Weather, over-population, and disease can cause unbalance in nature.
You also need to make sure there is not place for insects to hide and no diseases decaying matter for bugs to hide in. I you notice you have an insect problems and you plants are suffering, you can hand pick the insects of any plant and destroy them. You can also dislodge them with a strong spray of water.
But if you have an all out attack on your garden plants there is an insect spray you can make that will handle the problem quickly.
And yes, it sounds a bit strange.
Bug Juice Insect Spray
Collect a trowel of the damage-causing pests, and liquefy them in a blender with 1-cup (8 fl oz/250 ml) water. (I keep an old blender on hand to use for such purposes) Strain and dilute the mixture with 1-gallon (4 l) water, and pour the juice into a spray bottle.
Select plants that are infected with insects and spray. This mixture will not harm the plants. This is effective on nearly all pests, including beetles, squash and stink bugs, cutworms, army worms and even slugs
NOTE: Do not use bug juice on fleas, mosquitoes, or other blood-sucking insects that transmit disease.
Provide habitats for predators.
I had a toad that lived in my garden near the cumber patch for years. He either hid under the cucumber leaves or used the clay terra cotta planter I placed in the garden in a shady area. I also had a saucer of water sitting nearby for him. I enjoyed watching him in my garden areas.
Bats and birds are also helpful in keeping insects under control so provide houses for them to encourage them to stay in you backyard. The bat houses I place down by my creek. I am not fond of bats but they love mosquitoes and I don’t.
photo credit: Wagner Machado Carlos Lemes
Overall the best way to control insects is to notice the problems as soon as possible and take immediate action.