When strawberries suddenly disappear or show signs of being sampled just before harvest, common garden inhabitants are typically responsible for the damage. Diagnosing the specific culprit is the first step toward effective treatment. For the home gardener, the most immediate solutions involve establishing physical barriers and modifying the garden environment.
Identifying the Culprit by Damage Type
Observing the precise nature of the damage can help correctly identify which pest is enjoying your harvest. If you find fruit with a clean, partial bite taken out, or entire berries missing, the issue is likely a small mammal such as a squirrel, chipmunk, or mouse. Mammals typically sample a fruit and discard it after a few bites, leaving the rest of the berry uneaten on the ground.
Birds, which are active during the day, cause damage that appears as small, shallow peck marks, often concentrated on the top, reddest part of the fruit. This pitting or surface damage is usually not deep but renders the berry susceptible to mold and rot. In contrast, if the fruit has ragged, irregularly shaped holes, particularly on the underside or near the ground, this is the signature of slugs and snails. These soft-bodied mollusks also leave shiny, silvery trails of dried mucus on the fruit or surrounding leaf surfaces, confirming their presence.
For smaller, almost surgical damage, the issue may be insect pests. The strawberry bud weevil, sometimes called a clipper, damages the plant by laying an egg in a developing flower bud, then clipping the stem just below the bud, causing it to drop. Adult root weevils, which are nocturnal, leave unique scalloped or notched edges on the leaves, although the larvae cause more significant damage by feeding on the plant’s roots underground. Earwigs, which are also nocturnal, create small, deep holes in the fruit, distinguishable from slug damage by the absence of slime trails.
Physical Exclusion and Barrier Methods
The most reliable first line of defense is physically preventing the pest from accessing the fruit. For birds, a simple and highly effective solution is bird netting, which should be supported by hoops or stakes to create a cage-like structure. The netting must be held taut and positioned away from the fruit so that birds cannot perch and peck through the mesh. Secure the edges of the netting tightly to the ground, using landscape pins or logs, to prevent small ground animals from crawling underneath the barrier.
To deter larger climbing and digging animals like rabbits and squirrels, a dedicated fence or cage is necessary. A rabbit-proof fence should be at least two to three feet high, utilize a mesh size of one inch or smaller, and incorporate a barrier below the soil line. Secure the bottom of the wire mesh six inches deep into the soil, or bend the bottom six inches of the mesh outward in an “L” shape before burying it to prevent animals from digging directly under the barrier. Squirrels, being adept climbers, require a complete enclosure that includes a netted or wired top to be fully excluded.
Floating row covers offer a passive method to exclude a variety of insects and small pests during the fruiting period. These lightweight fabrics permit sunlight and water to pass through while blocking access for pests like weevils. When using a row cover, the edges must be completely buried or firmly secured to the ground to prevent crawling insects from entering the bed. For raised beds or containers, copper tape serves as an effective barrier against slugs and snails, as the copper reacts with the mollusks’ slime to create a mild electrical sensation.
Targeted Biological and Cultural Controls
While physical barriers prevent access, modifying the environment and actively managing populations are necessary for long-term control. Slugs and snails thrive in moist, dark environments, so reducing their available habitat is a priority. This involves removing old leaves, weeds, and general plant debris from around the strawberry plants, which eliminates their daytime hiding spots and overwintering locations. Removing this material also helps control earwigs, which seek refuge in the same damp conditions and will readily feed on ripening strawberries.
The timing and method of watering can significantly impact pest and disease pressure in the strawberry patch. Watering in the early morning is advised, allowing the plants and fruit surfaces to dry completely before nightfall. Wet foliage provides the moisture necessary for slugs to be active and for fungal spores, such as those causing leather rot, to germinate and spread. Using a soaker hose or drip irrigation system is the best practice, as it delivers water directly to the root zone and avoids splashing soil-borne fungal spores onto the fruit.
For active slug management, iron phosphate baits are widely available and are considered safer for pets and wildlife than older chemical options. These products work as a stomach poison, causing mollusks to stop feeding soon after ingestion. Prompt harvesting is another simple yet effective cultural control; removing ripe fruit as soon as it is ready eliminates the primary attractant for many pests. Pests like birds, earwigs, and sap beetles are drawn to overripe or damaged berries.