Beetles are present in most North American gardens. In sufficient numbers, the beetles can attack and overwhelm your plants, causing plant stress, loss of crops and even widespread plant casualties. Gardeners have several control options at their disposal. Combining both physical and chemical controls can help keep beetle populations in check to defend both the beauty and health of your backyard vegetation.
Keep your plants healthy. Water and feed the plants as appropriate for their specific species and variety. Healthier plants are less susceptible to diseases and insect infestations.
Mix a homemade plant spray. Stir 2 tbsp. of liquid dish soap into a quart of water. Pour the solution into a spray bottle and mist it on your vegetables, flowers and shrubs. The solution suffocates bugs and the soapy residue deters beetles that may feed on the plant foliage.
Setup yellow sticky traps around your garden. These traps lure various types of beetles to their demise, like the spotted cucumber beetle and many other kinds of insect pests. Place the traps near the vegetables or plants that are being attacked. Replace the traps when they're covered with dead insects.
Post beetle bait traps around your garden. These traps lure beetles using pheromones or other scents. Because traps are usually species-specific, get a trap for the specific type of beetle you're trying to control. Post the traps away from the plants that are being attacked, because you don't want to draw more beetles towards the plant.
Treat your landscape with the Bacillus thuringiensis bacterium, available from nurseries in spray and powder form. This bacteria naturally controls many kinds of beetles, such as the bean leaf beetle and the Colorado potato beetle, according to the University of Wisconsin. Apply according to the specific product's guidelines, as bacteria concentrations vary by product.
Spray your plants with a chemical control product, such as insecticidal soap or a pesticide containing permethrin. Follow the labeled instructions closely, since toxicity varies by brand. Always use a chemical that's approved for your specific landscape use. For example, only treat a vegetable garden with an insecticide intended for use on vegetables.