Japanese Beetles and Organic Gardens

Repellent Plants

• Plants that naturally repel Japanese beetles are garlic, chives, rue and tansy. Garlic and chives emit strong odors. Rue's foliage is aromatic and strong; some find the odor disagreeable. The taste is bitter. The perennial herb tansy has similar aromatic properties to rue. Interplant rue, garlic, chives and tansy within a vegetable garden border or among ornamentals.

Trap Crops

• Trap crops are plants used to attract Japanese beetles in order to keep them away from other plants. Useful trap flowers are borage, marigolds, evening primrose and white and pastel zinnias. Locate these trap crops away from the main garden in order to lure Japanese beetles to the trap crops. Interplanting trap crops in a vegetable garden is not a good idea because trap crops attract Japanese beetles.

Hand Picking

• Golden Harvest Organics recommends hand picking Japanese beetles in the morning because "dew on their wings keeps them from flying away and cooler air makes them lethargic." An effective method is to spread a blanket or sheet on the ground around the infested plant and shake the plant. A white or light-colored sheet works best to see the brown beetles. Alternatively, fill a can with soapy water. Hand-pick the Japanese beetles off the plants and drop them into the soapy water.

Biological Controls

• The USDA pamphlet "Managing The Japanese Beetle: A Homeowner's Handbook" recommends biological controls like predatory insects, parasites, nematodes and fungi. Biological controls take some time to incorporate into the environment, but their effects are longstanding. Most importantly, biological controls are target specific and do not harm other potentially beneficial organisms.