How to treat strawberry diseases: complete guide

The strawberry is a perennial plant, widespread in Italy, prized for its high productivity and the unique taste of the fruit.

However, strawberries can be susceptible to several diseases, which affect their productivity.

In this guide we will explore the main pathologies to be aware of in order to be able to identify and treat them in the most appropriate way.

Strawberry Botrytis

Botrytis, caused by the fungus Botrytis cinerea can be very dangerous for strawberries and is also known as gray mold. This disease can strike especially during wet springs and affects ripening flowers and fruit, which become covered with a characteristic gray mold, hence the name.

The main causes may be:

• Plant stress conditions.
• Very humid environments during flowering and in the postharvest period.

To prevent the strawberry plant from getting this disease, it is advisable to use products based on
Bacillus subtilis
, a naturally occurring microorganism that has a fungicidal function.

Powdery mildew

White blight, also called powdery mildew, is a disease caused by the fungus Sphaerotheca macularis, an Ascomycete fungus of the Erysiphaceaeilfamily .It can be recognized by the light-colored spots, on which a whitish, powdery mold forms, near which the tissues necrotize, turning a brownish color. Infection can cause abortion or malformed fruit, and achenes tend to protrude abnormally. Affected fruits are soft, less intensely colored, and tend to rot, and in the worst cases the splits on the fruit allow other fungi to establish themselves. It is also more prevalent in humid, typical spring climates.

The main methods that can be used to combat powdery mildew are sodium or potassium bicarbonate, to be diluted with water. In addition, sulfur-based products, such as Cuban zeolite and other corroborants, can be used to treat the disease.

Root rot

Regarding strawberry diseases, it is also good to know about root rot, a disease caused by several pathogenic fungi that attack the plant’s roots. In particular, Oomycetes of the genus Phytophthora, which thrive in very moist or poorly drained soils. Affected roots begin to rot, as a result, the plant cannot properly absorb water and nutrients, and so its leaves will appear yellowed and wilted, with stunted growth and a general lack of vigor.

Treating the disease requires removing rotten roots with a sterilized pruning tool and improving soil drainage to prevent future infections. In fact, a very humid climate promotes the development of pathogenic fungi, which are dangerous to strawberries. There are also specific fungicides to treat the disease, particularly those based on metalaxyl, which are effective against soil pathogens such as Phytophthora.

In addition to this, as mentioned several times in this guide, it is very important to prevent these kinds of diseases by following proper agricultural practices, such as balanced fertilization, regular soil cleaning and proper irrigation.

Poxing

Another disease potentially harmful to strawberry is pitting, caused by the fungi Mycosphaerella fragariae (sexual form) and Ramularia tulasnei (asexual form), two Ascomycetes of the family Mycosphaerellaceae. This disease mainly spreads in autumn and spring, in rainy climates with temperatures ranging around 20°C. We can recognize pitting by the brown and purplish spots that appear on strawberry leaves. In the more advanced stages, the leaves may also dry up, so it is very important to prune all affected parts in the early stages.

You can treat the disease with cupric products, such as copper oxychlorides.

Collar anthracnose

Collar anatracnose is another disease that can affect strawberries and is caused by the ascomycete fungus Colletotrichum acutatum. Also favored by humid climates, it manifests itself on all organs of the plant by means of hollow, dark lesions, which, in some cases, can become true bottlenecks, causing stunted development and wilting of the apical part. On the fruit it is also possible to notice round, sunken brown spots of dry texture, which expanding can cause a mummified appearance. Under favorable weather conditions, the spots may appear oily and become covered with orange exudates.

The main causes of the spread of this fungus are: the presence of infected breeding material and fungal propagules that remain on crop residues in the soil. Under certain environmental conditions, the latter are able to survive for up to several months. In addition, spore dispersal is promoted by wind, rain and irrigation water.

Since one of the main means of spreading this disease is through the use of infected propagation material, it is very important to think about prevention so as to protect one’s strawberry plants. For example, it is recommended to reduce practices that promote moisture, such as overhead irrigation or heavy fertilization, or to avoid extending the productive life of plants beyond one year.

On the other hand, in case the disease has already occurred, it is essential to remove all infected parts as soon as the first symptoms appear in order to be able to treat it in time. In addition, it is necessary to intervene with appropriate fungicides, especially towards the end of flowering and the beginning of fruit formation.

Methods of treating strawberry diseases

To be able to prevent these diseases from affecting our strawberry crops, it is essential to implement a number of strategies to keep the plant healthy.

Here are some of them:

• Avoid water stagnation: these may cause root rot, especially in very clayey soils.
• Cut off dry leaves: prevents the spread of pathogens and aerates plants. Very important to do especially after the production phase of the plant.
• Respect the necessary distances between plants: between one strawberry plant and another it is good to keep at least 20-25 cm distance, to prevent any diseases from spreading.
• Reduce moisture: wetting only the soil and not the plants.
• Fertilize sparingly: overfed plants are very vulnerable to disease attack.
• Remove daughter plants-these may cause the crop to thicken.
• Make preventive treatments: for example, with horsetail decoction or corroborants, which boost plants’ natural defenses and prevent diseases and attacks by dangerous insects. Also remember sulfur-based products, sodium or potassium bicarbonate, chitosan, cerevisiane-based, laminarin, Bacillus pumiluseBacillusamyloliquefaciens plantarum and sweet orange essential oil.
• Promote good air circulation between plants.
• Plant strawberries in well-drained, sunny soil.
• Monitor plant health-essential for early intervention at the onset of early signs of disease.

Following these tips can concretely prevent strawberry diseases.

Smart monitoring with Plantvoice

As mentioned in the previous paragraph, monitoring is crucial to having healthy and productive crops. In this context, agritech startup Plantvoice fits in perfectly, as it has developed an innovative sensor capable of monitoring plant sap in real time. Through the installation of a phytocompatible, minimally invasive device, Plantvoice allows you to stay up-to-date on plant conditions as it sends all the necessary information to an app in real time.

By investing in innovative technologies such as this, it is possible to cultivate more efficiently and sustainably, as it saves up to 40 percent of water, fertilizer and pesticides.

The diseases listed in this guide are potentially very dangerous for strawberry crops. So, in addition to adopting the right agricultural practices, using innovative monitoring tools can really make a difference to the health of your plants.