Strawberry Leaf Spot: Symptom Identification and Control Methods

Strawberry is a fruit with relatively high economic value, rich in nutritional value, and deeply loved by consumers. During the cultivation of strawberries, they are very susceptible to disease attacks, especially leaf spot. So what symptoms does strawberry leaf spot have? How to control it?

1. What symptoms does strawberry leaf spot have?

1. Strawberry leaf spot initially appears on the leaves as small dark purple spots, which after expanding become nearly round or oblong, with a deep purplish-red-brown edge and a grayish-white to grayish-brown center, with faint concentric rings, making the entire lesion look like a snake's eye.

2. When humidity is high, strawberry leaf spot produces a white powdery mold layer on the surface of the lesions, and later many small black dots can form on the lesions. In severe cases, the lesions are densely distributed on the strawberry leaves, and the diseased leaves quickly necrose and wither within a short time.

3. When there are too many leaf spot lesions on strawberry leaves, the leaves will dry up. A large outbreak will affect leaf photosynthesis, causing the plant's disease resistance to decrease, and in severe cases the strawberry plant's growing point turns black and dies.

2. How to control strawberry leaf spot?

1. Before transplanting, clear weeds from the field and its surroundings, and burn them in a centralized manner or compost them; plow deeply to destroy stubble, promote the decomposition of diseased plant residues, and reduce sources of disease and pests.

2. Practice reasonable crop rotation; paddy-upland rotation is better.

3. Select disease-resistant varieties with strong growth vigor, high fruit-setting rate, cold tolerance, shade tolerance, and resistance to gray mold, viral diseases, powdery mildew, and bud blight. For mother plants, choose disease-free seedlings with pure variety characteristics, robust growth, and well-developed root systems.

4. Three days before transplanting, spray a mixed pesticide for disease and pest control once, transplant with soil and with pesticide, and remove diseased and weak seedlings during transplanting. This is one of the important measures for disease and pest control. Before covering the seedlings with soil, spray a mixed pesticide for disease and pest control once. According to seedling condition, if growth vigor is weak, 0.3% urea can be added.

5. Choose fields with convenient irrigation and drainage, open drainage ditches well, lower the groundwater level, and achieve no standing water after rain stops; after heavy rain, clear the ditch system in time to prevent moisture retention and reduce field humidity. This is an important measure for disease prevention, because many diseases are caused by high humidity, so pay attention.

6. For fields with abundant soil-borne pathogens or severe underground pests, apply medicinal soil for disease and pest control in holes or furrows before transplanting.

7. Apply compost fermented with effective microorganisms or fully decomposed organic fertilizer. Do not use pathogen-carrying fertilizer, and the organic fertilizer applied must not contain diseased residues of crops in the same family.

8. Adopt soil testing and formulated fertilization technology, appropriately increase the application of phosphorus and potassium fertilizers, strengthen field management, cultivate strong seedlings, and enhance plant disease resistance, which helps reduce disease.

9. Plastic film mulching cultivation can prevent soil-borne pathogens from harming the aboveground parts of the plants.

10. Control pests in time to reduce plant wounds and reduce transmission routes for pathogens; when disease occurs, promptly remove diseased leaves and diseased plants, take them out of the field and burn them, and apply pesticide or quicklime to the diseased planting holes.

11. During high temperature and drought, irrigate scientifically to increase field humidity and reduce the harm and virus transmission by aphids and small brown planthoppers. Continuous irrigation and flood irrigation are strictly prohibited. Preventing water droplets from splashing when watering is an important measure to prevent this disease.

12. For greenhouse cultivation, before transplanting or raising seedlings and preparing the soil, and after harvest, thoroughly remove diseased residues and fallen leaves, spray pesticide on the surfaces of the greenhouse film, soil, walls, and trellis materials for disinfection and sterilization, and ventilate appropriately to remove moisture. Alternatively, during the summer fallow period, irrigate inside the greenhouse, cover the ground with plastic film, close the greenhouse for several days, and use high temperature for sterilization; implement strict quarantine, strictly inspect imported seedlings, and once found, destroy them immediately. Transferring seedlings to other places is strictly prohibited.