Causes, Symptoms, Chemical, and Biological Management of Strawberry Crop Pests and Diseases

Causes, Symptoms, Chemical, and Biological Management of Strawberry Crop Pests and Diseases

Because of its plentiful antioxidants and high vitamin sources, strawberries are a vital minor fruit crop that is farmed all over the world. California, which produces more than 90% of the strawberries in the US, is the state that produces the most strawberries, followed by Florida. The plant has a short stem and a crown of trifoliate leaves. near the surface.

Depending on the species, the leaves exhibit a range of traits. Some species have evergreen leaves, whereas others have leaves that wither and drop off in the winter. White flower stalks are produced by the plant from the crown. The fruit of the plant is fleshy and scarlet with little seeds on the outside. Strawberry plants have a 2-4 year economic life before needing to be replaced and can reach a height of 20–25 cm.

How to keep the strawberry crop free of parasites and diseases

The production of strawberries is frequently threatened by a variety of arthropod pests, including bug and mite species. Armyworms, thrips, Frankliniella and Scirtothrips spp., two-spotted spider mites, and root-boring insects are some of the main arthropod pests that influence strawberry production. And numerous hemipterans, notably the tarnished plant insect, harm strawberry leaves and fruit. The typical pests and illnesses that affect the strawberry crop are listed below.

Causes, Symptoms, Chemical, and Biological Management of Strawberry Crop Pests and Diseases

Insects and pests


It is a tiny bug that eats the inner portions of flowers. Strawberry blossoms are occasionally infested by a number of species. Before going to strawberries in the summer, these insects breed on weeds and grasses in the spring. At the base of blossoms and sensitive young leaves, they lay their eggs in the plant tissue. Thrips start feeding on the seeds and the inner surface of the hull as soon as the buds open. Finally, when the fruit enlarges and the seeds separate, thrips eat the fruit in between them.

Damage indications

Thrip nymphs and adults harm plants by tearing at the tissues of the buds, flowers, and leaves before sucking the sap from the leaking tissues.

The stigmas and anthers of strawberry blooms that have been attacked by thrips prematurely become brown and wither, but not before fertilization.

The surface of the berries may become fractured and discolored when populations are high.

Surface russeting can be seen around planting materials from late green to ripe fruit. This might cause the fruit to appear bronze and seedy.

The fruits will be being sucked on by thrip larvae and adults.

Biological Surveillance

Thrips are fed on by naturally occurring tiny pirate bugs. Orius are also sold commercially, however the scheduling and release rates have not been established.

Thrips that feed on plants are controlled by predatory thrips, green lacewings, tiny pirate bugs, mites, and some parasitic wasps.

Chemical safeguards

On strawberries that have received an organic certification, use sprays of the Entrust formulation of spinosad, azadirachtin, Beauveria bassiana, or mixtures of these items.

Use spinetoram, malathion, acetamiprid, pyrethrin, or piperonyl butoxide as insecticides to suppress thrips.


The number of greenhouse whiteflies tends to grow throughout the fall, peaking in late fall into the winter. When the weather is warm, whiteflies can complete a generation in as little as 18 days. The adults of all species of whiteflies are around 1 mm in size and have four membranous wings covered in a white powdered wax that makes them easily distinguishable from other insect plagues.

Damage indications

The virus reduction in strawberries has been connected to greenhouse whiteflies because they can spread viruses.

Whiteflies may directly lower agricultural yields and impede plant growth because they feed on leaf sap.

During feeding, they also create sticky honeydew. Honeydew can cover plants, allowing black sooty mold to develop on them.

When there is a serious infestation, there is premature defoliation.

Chemical regulation

When the population of whiteflies starts to rise, imidacloprid applications can be controlled. Apply before whitefly populations considerably rise as it will take 2 to 3 weeks for adult whiteflies to be controlled after application.

Malathion is an organophosphate, while fenpropathrin is a pyrethroid. Fenpropathrin can only be used in two applications per year as a result.

Biological Surveillance

Greenhouse and iris whiteflies are typically managed in most crops by parasitic wasps and other natural predators.

Whiteflies have parasitic wasps from the genera Encarsia, Eretmocerus, and Prospaltella as natural enemies, as well as big-eyed bugs, pirate bugs, and lacewing larvae.

Globally, Encarsia Formosa is employed to control greenhouse whiteflies. However, more investigation is required to ascertain whether releasing this or other parasites can assist in halting the population growth of whiteflies in field settings.

Causes, Symptoms, Chemical, and Biological Management of Strawberry Crop Pests and Diseases

Unclean Plant Bugs

Strawberries are targeted by the western tarnished plant bug. The adults appear to be nomadic, shifting from plant to plant as each one starts to bloom. Adults overwinter in weeds. The adults quickly colonize strawberries in the spring when the rains stop and the weeds dry out. Although these pests do not like strawberries as a host plant, the lack of other more alluring plants in late spring may be the reason for the widespread colonization of strawberries. Between April and August, at least two generations of strawberries grow in this region.

Damage indications

Fruit that has been deformed or "cat-faced" by tarnished plant insect feeding. This harm is the result of nymphs or adults feeding on the seeds as the fruit grows.

Damaged seeds usually have a brown exterior and an inside that is hollow.

Strawberries that are day-neutral or everbearing could be more negatively impacted. However, the existence of malformed fruit does not always signify a problem with tarnished plant bugs. Other conditions, such as inadequate pollination, might also result in misshapen fruit.

In the Southeast, poor pollination is frequently highly prevalent during the first picking of spring-fruiting strawberries when the weather is frequently less conducive to bee activity.

Chemical regulation

Malathion, naled, carbamate methomyl, and organophosphates are a few of the pesticides found in strawberries.

bifenthrin, fenpropathrin, and the pyrethroids. Although the pyrethroids offer long-lasting control, there are worries about how they might affect the natural enemies that already exist.

Different pre-harvest intervals are listed on the labels of various pyrethroids. Labels are also present for Malathion and Assail.

Biological defense

Big-eyed bugs, Geocoris spp., minute pirate bugs, Orius spp., green and brown lacewings, and Chrysoperla are some of the naturally occurring predators that are at risk.

White flies, lepidopteran pests, Lygus nymphs, and eggs are consumed by Hemerobius species, damsel bugs, Nabis species, convergent lady beetles, and several spider species.

White sticky traps can be used to keep an eye on adult tarnished plant bugs. These traps are not meant to kill plant bugs; rather, they are meant to identify when they are active in the spring.

The spider mite with two spots

The two-spotted spider mite can infest strawberries and several other crops. Black Nightshade, little stinging nettle, and valiant soldier are additional weeds that contain it. The adult females spend the winter in protected areas within the crops. In the spring, they become active. They are simple to identify due to two black dots on their bodies rather than their color. There are five developmental phases in addition to eggs, larvae, protonymphs, deutonymphs, and adults. In 5 to 20 days, depending on the temperature, the life cycle will complete.

Damage indications

Spider mites rasp away the leaf surfaces to feed on the plant sap.

The first indication of damage is speckling and mottling on leaves.

When there is a severe infestation, the leaves are purple with white webbing between them.

More than 75 mites per leaflet can severely damage plants and give them a stunted, dried-out, and red appearance.

severely damaged leaves die and drop off.

Biological defense

The most often utilized predatory mites for spider mite suppression are Phytoseiulus persimilis, Neoseiulus californicus, Neoseiulus fallacis, and Galendromus occidentalis.

Plantaeulus persimilis P persimilis is a specialized predator that only eats pest mites. It feeds fiercely, multiplies quickly, and feeds aggressively.

Chemical regulation

Before employing a powerful miticide with a different mode of action to manage resistance, do not use cyflumetofen more than once.

Acequinocyl: It should only be used twice a year. There should be a minimum of 21 days between treatments.

Spiromesifen should only be used twice every crop season.

Etoxazole is the most efficient drug for killing eggs and young mites.

The root-knot nematode

A microscopic organism, that is. During the first stage of the larvae's development, the egg has its first molt. Second-stage larvae find and infect plant roots or, in rare circumstances, foliar tissues after emerging from eggs. The eggs hatch and larvae emerge within 4 to 8 weeks, depending on the temperature, to complete the life cycle. 21°C to 26°C is the ideal soil temperature range for nematode development.

Damage indications

Infected plant patches can be seen throughout the orchard.

The host root system develops galls as the first sign.

When infected roots branch out widely from the gall tissue, they become knobby and knotty.

Plants that have been severely affected have a diminished root system and nearly no rootlets. The roots significantly impede the movement and absorption of water and nutrients.

Plants are more susceptible to bacterial and fungal root diseases if they have nematode infections.

Biological defense

New nematode management methods are required because chemical nematicides are so hazardous. In this approach, a filamentous fungus can be a promising biocontrol agent.

The primary filamentous fungi researched and employed as biological control agents against nematodes as resistance inducers are those of the genus Trichoderma, mycorrhizal fungi, and endophytic fungi. Through parasitism, antibiosis, paralysis, and the production of lytic enzymes, they can directly lessen the harm caused by plant-parasitic nematodes.

Chemical control

Methyl bromide is only permitted for use in strawberry nurseries through pre-shipment exemptions and quarantine.

a liquid form of chloropicrin that permeates the soil as a gas. Both insects like nematodes and soilborne fungal diseases are effectively controlled by it.


The crowns, stems, leaves, and fruits of strawberries are all affected by the anthracnose fungus. Anthracnose is identifiable by the orange slime of spores that develops on the plant sections that it kills. These spores are dispersed by overhead water splashing. So, even if your plants can suffer, you can at least save the harvest when there is no rain and no overhead watering after the fruit set.

Disease signs

Anthracnose can be caused by three distinct fungi, however they all have comparable signs and symptoms:

On both green and ripe berries, the patches resemble wet berries.

Instead of having a single, huge spot like Alternaria black spot, each berry contains multiple smaller spots. Fruit that is dried out may look mummified.

black, sunken, or decaying flower petals

a sizable patch of leaves that are dark brown or black

Control and management of chemicals

Fungicides with a copper base are the main method of controlling anthracnose. However, copper can build up in the soil to dangerous levels, damaging earthworms and bacteria.

As soon as you can, remove diseased berries and plants.

routine weed control

Maintain proper thinning and spacing to keep air flowing.

Mulches made of straw slow the spread of spores.

A powdery mold

Instead of old leaves, the powdery mildew typically targets young, budding leaves. Spores are produced by mildew colonies once they have taken control of a leaf. These fungi's spores touch down on flowers. The distorted blossoms are covered in white, fluffy patches, and because they do not grow properly, they are unable to produce fruit. After flowering, powdery mildew does not pose a hazard to the fruit but can a few days later infect the seeds. A strawberry with mildew has a "seedy" appearance and a rotten flavor.

Symptoms of the disease: 

As the mildew spreads, leaves on the bottom surface get purple, then turn red, and leaves on the top surface develop purple, red, and brown blotches.

The upward curling of the leaf margins is a sign of early illness.

The upper leaf surfaces then develop erratic, purple blotching, frequently along prominent veins. The foliage appears fragile.

Fruit can be affected by powdery mildew at any stage.

dull fruit, both young and old, with obvious planting materials

Control and management of chemicals

To avoid powdery mildew, use soaps that are also used to repel insects or micronized sulfur. These generally safe products should be used before powdery mildew develops.

Additionally beneficial is a spoonful of baking soda (15 grams) in 4 liters of water.

Red core/Red stele

The soil-dwelling fungus Phytophthora fragariae is responsible for this root rot. Spores that diseased plants produce have the ability to infect healthy roots. These spores will travel through the soil and into the root tips, where they will begin to proliferate inside the root system. After infection, the roots don't begin to decompose for a few days. These decayed tissues release spores, which eventually mix with the spores in the soil. The infected region of a bed typically follows a distinct pattern.

Disease signs

Older leaves change color, especially around the border, turning yellow or red.

The brick red staining in the middle (stele) of living white roots is a sign that aids in the diagnosis of red stele.

The crimson hue may cover the entire length of the root or simply appear briefly above the dead root tip.

The plants' growth will slacken and turn drabby bluish-green. The plants will recover considerably in the spring.

A plant that is impacted will produce few or no blooms.

The little fruits will shrivel up. The roots' root-hair is absent.

The core cylinder will appear reddened when the main roots are severed.

Control and management of chemicals

Mefenoxam should be used as a banded spray to the soil or through drip irrigation up to three times beginning at transplanting or after the earth thaws before the first bloom.

Fungicides containing aliette and phosphorous acid can be sprayed on leaves, roots, or by drip applications.

The Botrytis Rot (Gray Mold)

200 plants, including our precious strawberries, are home to nasty gray mold. According to estimates, this mold can reduce strawberry production by up to 80%. Its growth requires a temperature range of 14°C to 22°C and high humidity. The fungus infects ripe strawberries before or after harvest, turning them into ugly fluffy gray mold.

Disease signs:

Flowers, fruit, petioles, leaves, and stems will all be attacked by the fungi.

Fruit stalks and flowers that become infected while flowering quickly perish. Fruit that is both green and ripe rots brown.

It covers the entire fruit, which is then covered in a thick layer of dry, gloomy spores.

The rot may begin on any part of the fruit, although it is typically found on the fruit's calyx end or the sides of fruit that are in contact with other rotting fruit.

Control and management of chemicals

keep the plants' airflows appropriate

Composting diseased or dead plant matter is not advised. Take it out and burn it.

Both before and after an infection, natural fungicides like neem oil are effective. To lessen the possibility of botrytis outbreaks, squirt diluted neem solution directly onto plants.

Fungicides made of copper soap will aid by shielding plants from disease spores. Apply as soon as flowering begins and then every 7 to 10 days till harvest.

Leaf blotch

Due to prolonged damp times in the late spring, strawberries are particularly vulnerable to this illness. Mycospharella fragarieae, spores that blow into your garden or spread from dead foliage that has overwintered, is what causes the disease. Fortunately, leaf spot is a cosmetic issue that typically has little impact on your fruit or production. However, if it spreads, it might seem as strawberry-colored leaves.

Damage indications

Additionally, runners, berry tops, and fruits may exhibit the symptoms. But leaf spot symptoms must be separated from blight and pest symptoms.

The patches may eventually have rusty-brown edges and tan or white centers.

shallow black dots on fruits (up to 14 inches)

Black or brown fruits with a leathery feel around the dots.

Control and management of chemicals

After the season is through, get rid of all the old plant matter.

Cut down plants once they have finished bearing fruit to promote fresh development.

Irrigation from above should be avoided

Make sure the plants have enough airflow.

After the onset of the first symptoms, strawberries can be treated for common leaf spot disease with fungicides based on chlorothalonil, myclobutanil, or triflumizole.


Along with pests, strawberry diseases can harm the fruit, flowers, leaves, roots, and crowns of strawberry plants. In rare cases, this might result in the complete plant collapsing. At the same time, when symptoms are noticed, many issues brought on by bacteria, fungus, molds, and viruses can be treated. To stop infections in their early stages, you should be aware of the symptoms of infections and how to treat them.

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