Growing beans can be a rewarding gardening experience, but these plants often attract various animals that can damage or consume the crop. Protecting your bean plants requires understanding which animals are responsible and how they cause harm, which then allows for effective deterrent strategies and a successful harvest.
Mammalian Bean Eaters
Mammals like deer, rabbits, groundhogs, and squirrels frequently target bean plants. Deer consume all parts of the bean plant, including leaves, shoots, and flowers. Signs of deer damage include torn or nibbled foliage, often from the top down, and they can quickly reduce a plant to its stem. Rabbits, particularly cottontails, prefer the tender young shoots and leaves of bean seedlings, leaving clean-cut damage at a 45-degree angle on the stems.
Groundhogs, also known as woodchucks, feed on a variety of garden vegetation, including bean plants, and typically leave a smooth, diagonal cut on the bitten ends. Squirrels and chipmunks often nibble on bean shoots and leaves, especially those of young plants. Voles, burrowing rodents, primarily attack bean plants from underground, damaging root systems and lower stems.
Avian and Insect Bean Eaters
Birds and insects also contribute to bean plant damage. Birds like pigeons and sparrows can pull out newly sprouted seedlings. Among insects, several species harm bean plants:
Bean weevils, in both adult and larval stages, primarily damage seeds by boring into them, affecting viability, especially in stored legumes.
Mexican bean beetles, which resemble yellow ladybugs, skeletonize leaves by eating the tissue between veins from the underside, creating a lacy appearance. Both adult and larval stages feed on leaves, and sometimes on blossoms, pods, and stems.
Aphids are small, soft-bodied insects that suck sap from leaves, stems, and tender plant parts, causing leaves to curl, yellow, or wilt. They also excrete a sugary substance called honeydew, which can lead to sooty mold growth.
Slugs and snails create irregular holes in leaves, often leaving a silvery trail, and can be particularly problematic for young seedlings.
Bean leaf beetles create round, 1/8-inch diameter holes in leaves and can also feed on pods, affecting their appearance.
Protecting Your Bean Plants
Various strategies can help protect bean plants from animal damage.
Physical Barriers
Physical barriers are effective, such as installing fences around the garden perimeter to deter larger mammals like deer and rabbits. For smaller animals and birds, garden netting or row covers can be placed over young plants, allowing sunlight and water to pass through while blocking pests. Trellis netting not only supports climbing bean varieties but also acts as a physical barrier against some pests and reduces ground rot.
Repellents
Repellents can also be used, though they often require frequent reapplication. Commercial repellents or homemade sprays containing ingredients like cayenne pepper or blood meal can deter some animals. However, it is important to ensure any applied substance is safe for food crops and does not negatively impact pollinators.
Companion Planting
Companion planting involves placing specific plants near beans to deter pests naturally. For example, marigolds, nasturtiums, garlic, onions, basil, dill, and rosemary are known to repel certain insects like aphids and bean beetles through their scent or by acting as trap crops.
Cultural Practices
Cultural practices contribute to pest management. Maintaining a clean garden by removing plant debris can reduce overwintering sites for pests like Mexican bean beetles. Handpicking larger insects and their egg clusters from the undersides of leaves can also help control populations. Ensuring adequate plant health through proper irrigation and balanced fertilization can make plants more resilient to pest damage. For instance, avoiding excessive nitrogen can help prevent higher aphid populations.