What’s Eating My Strawberries? 7 Strawberry Pests to Watch for

Strawberries are delectable and one of the sweetest summertime rewards from home-grown plants. Unfortunately, many insects feel the same way about their flavorful hosts. From common garden bugs to specialists, strawberries are susceptible to pest invasions that rob us of their sweetness by the basketful.

To minimize pest damage, setting strawberries up for success with the best cultural conditions gives a strong foundation. Sometimes, pest problems are unavoidable where they’re most active. To reduce their impact, grow a diversity of flowering species to attract predatory insects like ladybugs, parasitic wasps, hoverflies, and green lacewings. These “beneficial” insects help manage the population at the egg, nymph, and adult phases.

Here are seven of the best ways to deal with strawberry pests in your garden.

About Strawberries

Strawberries are relatively easy to grow. The herbaceous perennials are in the Fragaria genus that houses about 20 species and numerous cultivars. Colorful and sweet, their fruits range from scarlet to white to pink to purple. Five-petaled flowers are usually bright white, sometimes charmingly pink, with yellow centers. Dark green leaves in sets of three line the stems to form an attractive backdrop. 

Strawberries produce at varying times in the season, depending on the cultivar. June-bearing strawberries feature a hefty yield of large berries early (late spring/early summer). Everbearing varieties produce smaller berries throughout the growing season. They bring a continual burst of sweetness to beds, pots, and hanging baskets. Flowers and berries emerge in a heavy flush in spring and about every six weeks until frost.

Plant strawberry crowns in the spring in northern climates where they experience cool, mild summer temperatures. In climates with hot summers, plant them in the fall to enjoy in the cooler months. You can also get a head start by starting seeds indoors before transplanting them after the final frost.

Tarnished Plant Bug

Tarnished plant bugs are one of the most common offenders of strawberries. They puncture and feed on developing fruits, resulting in “cat-faced” puckering and misshapen berries. 

Tarnished plant bugs (Lygus lineolaris) are greenish-brown and bronzy with a pale yellow triangle marking on their backs. The adults overwinter in leaf debris and other protected areas to begin laying eggs in spring. They lay eggs in weedy patches, and the tiny nymphs emerge and begin feeding on nearby strawberry blossoms and developing seeds.

These strawberry pests are most active just after petals drop and as later-season berries emerge. If tarnished plant bugs are a problem in your area, try growing early June-bearing varieties. Early yields may miss the peak population of feeding nymphs.

Treatment

There are a few measures to try to minimize tarnished plant bug nymphs. The first is to block their access to the strawberry hosts by using a floating row cover on young plants. Leave it during flowering for pollination, returning it at night and post-bloom.

Horticultural soaps and oils are effective in reducing infestations. Because these affect all kinds of insects, including pollinators and beneficial predators, be sure to follow application directions and apply them in the morning before pollinators are active.

Several predatory insects naturally manage populations. For tarnished plant bugs, these include parasitic wasps, damselflies, and assassin bugs, among others. Milkweed, yarrow, dill, sweet alyssum, Rudbeckia, and Joe Pye weed attract the beneficials.

Lastly, keep the berry patch weed-free to limit egg-laying and overwintering sites. Clear debris after the harvest to minimize cool-season sheltering spots in the plot.

Slugs and Snails

Slugs and snails enjoy fresh berries as much as we do. They slide across leaves and feed on the berries and soft shoots.

You may see the creatures in their most active times of evening or early morning. Or, you’ll notice deep holes in the fruits. 

Treatment

Scout during their most active times to hand-pick slugs and snails from plant surfaces. In the middle of the day, they’ll tuck in under leaves or on the mulch and soil around the crowns. Lure them with lettuce leaves or citrus rinds and collect them in the morning.

If numbers increase, bait them with beer or soda traps by filling a shallow dish and placing it at soil level. Remove mulch from around the crop to stave off protective hiding spots. Target irrigation to reduce moist conditions, which are an inviting habitat for the creatures. Drip irrigation at the base delivers water directly to the roots without wetting the overall surface area.

Diatomaceous earth scattered around the base of the stems contains sharp particles that harm soft-bodied creatures as they crawl. Reapply after rains to maintain the boundary.

Aphids

There are a number of aphid species that impact Fragaria, including its own strawberry aphid (Chaetosiphon fragaefolii). Aphids reproduce quickly and congregate in numbers on the undersides of leaves. The sap-feeding insects prefer new growth like young plants and tender shoots, and leaves. They also damage buds and blooms with their concentrated feeding. 

Aphids are pear-shaped and soft-bodied in light yellow, green, pink, brown, or black. You’ll spot them in groups, and they leave behind a sugary “honeydew” waste. The sticky substance can lead to black, sooty mold, which is unattractive but not usually harmful. It’s a telltale sign that a sap-sucker is present.

In dense populations, aphids stress plants. They’re also vectors for fungal spores and pathogens. They spread diseases and viruses as they travel between plants, weakening them as they go. Foliage may curl and yellow, and growth may stunt in an aphid infestation. Leaf spot, mottling, and distortion may follow as signs of disease.

To prevent aphids, water consistently to achieve evenly moist soil for healthy growth that resists infection. With many natural aphid predators, growing a variety of blooming plants to draw a diversity of insects offers natural pest control.

Treatment

If you spot aphids or their honeydew, try spraying them with a strong stream of water (like spider mites and other soft-bodied insects). Sap-sucking insects have piercing mouthparts, and the spray is meant to detach the mouthparts from their bodies. Spray in the morning to minimize daily damage and to let leaves dry in the day’s sun and breeze, minimizing damp conditions that cause fungal problems like powdery mildew. 

Effective for larger outbreaks are horticultural soaps and oils. Diatomaceous earth dusted over leaves and the surrounding soil may lessen the spread. The sharp powder damages any soft-bodied insects, in addition to slugs and snails.

Weevils

Several weevils act as strawberry pests, including strawberry root weevils, rough strawberry root weevils, and strawberry bud weevils (Otiorhynchus spp.). With weevils, you may see notches in leaves, darkening of foliage and stems, bunching leaves at the crown, stunted growth, and decline. Weevils often take shelter during the day and feed at night, and their damage is often the first indicator.

Weevils are dark-bodied with elongated head parts, like snout-nosed beetles. The adults lay eggs at the base of the crown for easy feeding as the larvae hatch. The larval phase of root weevils is when the real damage occurs, in the tunneling and feeding. The white grubs of root weevils feed on roots and crown stems. Root weevils overwinter in the grub stage to emerge as adults in spring. They feed on leaves (causing the notches) before egg laying.

The bud weevil feeds on strawberry buds in spring, when the adult female pierces the bud to lay eggs. She then clips it to prevent the flower from opening to allow the larvae to feed.

Treatment

Practice good sanitation by keeping the patch weed and debris free. Plant strawberries away from wild brambles like blackberry and elderberry, which harbor weevils. Pyrethrin sprays or powders effectively reduce populations. Sticky bands prevent any from entering the canopy, however, these also affect any other insects or small mammals.

Sap Beetles

Sap beetles target ripe, juicy fruits, including cracked or damaged ones. They’re drawn to fermented sap. They create holes in the fruits and may spread diseases as they travel and devour berries.

Sap beetles are small, dark, and oval-shaped, sometimes with spotted backs, depending on the species.

Treatment

The best treatment is prevention by removing dropped or damaged fruits. Pick strawberries at peak ripeness to avoid luring the pests. If you’re growing many plants and have an outbreak, try “trap” trays of sugary liquid at the perimeter to serve as bait. Use molasses, beer, vinegar, or rotting fruit to draw sap beetles away from the crop.

Mites

There are two main mites that target Fragaria: two-spotted spider mites and cyclamen mites. Spider mites are sap-sucking insects that harbor on the undersides of leaves. In the case of cyclamen mites, they hide in folded, developing leaves at the crown to feed. Their piercing mouthparts feed on cellular tissue. Mites are tiny, but you’ll notice their foliar damage and light webbing between stems and leaves.

Colonies of the insect live around leaf veins and mid-ribs underneath. Females lay eggs, and the larvae quickly feed on sap and tissues. Adults feed and produce tight webs around leaves, stems, and branches.

The foliage shows pale spots, light yellowing, and stippling on leaf surfaces. Leaves become bronzy, stiff, and curl, and may prematurely drop.

Spider mites occur in hot, dry, dusty conditions. They flock to plants experiencing drought stress and water fluctuations.

Treatment

Beneficial predatory insects, including predatory mites, help control populations. If you detect spider mites, spray the leaves and stems with a strong stream of water early in the day to deter and knock insects off. Spraying also rinses dust and mitigates dryness.

Prune away any affected portions and dispose of the debris. Skip adding it to the compost pile, which can harbor and spread the insects.

A simple horticultural soap or oil rids severe cases. Plant-based insecticidal oils like garlic extract, clove, rosemary, mint, and cinnamon oils are effective organic controls.

To prevent mites, water regularly to maintain evenly moist soils. Consistent moisture (but not oversaturation) fosters the best flowering and vigor during the warm season. Tidy and renovate beds after the season to minimize habitat for ongoing generations.

Meadow Spittlebugs

Spiddlebugs (Philaenus spumarius) are a leaf and stem-feeding strawberry pest that has a wide palette. The nymphs produce a foamy “spittle” in their wake. Nymphs are pale green, orange, or yellow. Adults are brownish black and tan. Like aphids, they may not do serious damage. In numbers, they may cause smaller fruits as they feed on the sap in the stems.

Meadow spittlebugs are most frequent in cool, moist conditions. Populations are showing lower numbers in recent years as conditions change.