Growing strawberries can be frustrating when the berries disappear or are damaged just before harvest. This common problem means you are competing with local wildlife and pests who find the sweet, ripe fruit irresistible. Protecting your strawberry patch requires identifying the specific creature responsible for the damage, as a solution effective against a bird will not deter a slug. By observing the type and location of the damage, you can implement targeted strategies to secure your crop.
Identifying the Culprit by Damage Pattern
The first step in protecting your harvest is analyzing the evidence left behind on the fruit and foliage. Slugs and snails are primarily nocturnal feeders that leave ragged, irregular holes in the ripe fruit, often consuming the part closest to the ground. The unmistakable sign of these mollusks is the silvery slime trail left on the leaves and fruit, confirming their presence even when they are not visible.
Damage from vertebrate pests like birds and small mammals is typically more substantial. Birds often leave large, deep pecks on the top or side of the strawberry, sometimes taking a single bite and leaving the rest to rot. Small birds like robins or starlings may consume smaller berries whole. House finches peck holes that leave the fruit susceptible to decay.
Rodents, including mice, voles, and squirrels, frequently remove entire berries or leave large, jagged bites on the fruit. Voles are subterranean and may gnaw on the roots and crowns of the plants, but they also feed on the fruit away from the plant. Squirrels are opportunistic feeders, often leaving behind partially eaten fruit dropped nearby.
Insect damage presents smaller, more specific patterns on the fruit and plant structure. The strawberry bud weevil, sometimes called the strawberry clipper, causes damage by clipping the flower buds before they open, leading to a loss of potential fruit. The tarnished plant bug feeds on the developing fruit, causing the berries to become deformed, resulting in a characteristic misshapen or “cat-faced” appearance.
Controlling Insect Pests and Slugs
Management of small invertebrate pests involves creating physical barriers and utilizing organic controls. For slugs and snails, iron phosphate baits are an effective, organically approved molluscicide that is less toxic to other wildlife. These granular baits are scattered near the plants and interrupt the mollusks’ digestive system after ingestion.
Another effective method for deterring these soft-bodied pests is applying a barrier of diatomaceous earth (DE) around the base of the plants. This fine powder is composed of fossilized marine organisms whose sharp edges abrade the slug’s protective waxy coating, leading to dehydration. The DE barrier must be reapplied after rain or heavy watering to maintain effectiveness.
Traps and habitat management can significantly reduce slug populations. Simple beer traps, consisting of a shallow dish sunk into the soil and filled with beer, attract slugs who fall in and drown. Removing plant debris, excessive mulch, and reducing watering frequency helps eliminate the cool, moist hiding places slugs seek out during the day.
For insect pests, like weevils and aphids, general garden sanitation is important because many species overwinter in leaf litter and weeds. Introducing beneficial insects, such as ladybugs and lacewings, provides natural control, as these predators feed on soft-bodied pests like aphids. In cases of heavier infestation, applying insecticidal soap or neem oil helps control populations without leaving harmful residues on the fruit.
Deterring Birds and Mammals
Protecting strawberries from larger, mobile pests like birds and mammals requires exclusion methods that physically prevent access to the fruit. Fine mesh netting is the most reliable way to save the crop from birds, but it must be properly installed over a frame or hoops. The netting needs to be elevated above the plants so birds cannot peck the fruit through the mesh.
Securing the edges of the netting tightly to the ground is important to prevent birds from crawling underneath or becoming trapped. For a more robust solution, building a fruit cage with a wooden or PVC frame covered in fine mesh creates an impenetrable barrier. Placing reflective tape or old CDs near the patch also acts as a visual deterrent, as the flashing light temporarily confuses and repels birds.
Mammals like rabbits, raccoons, and squirrels are persistent and require more substantial defenses. A low-profile wire fence, about two feet high and partially buried, can deter rabbits and other ground-level foragers. For voles and mice, using raised beds lined with hardware cloth at the bottom prevents these burrowing rodents from reaching the plant roots and crown.
Motion-activated sprinklers are an excellent, humane deterrent for various mammals and birds, as the sudden spray of water startles them away. While not a complete solution on their own, physical deterrents like a plastic owl or snake can be used, but they must be moved frequently. If the animals realize the decoy is stationary, they will quickly lose their fear and return to the strawberry patch.