Common Diseases and Preventive Measures of Strawberry in Greenhouse

Spring is the period of vegetative growth and reproductive growth of strawberries. Strengthening strawberry spring management is extremely important to increase strawberry yield and quality. The following are common strawberry diseases and preventive measures.

1. Powdery mildew disease

1.1 Causes and hazards of powdery mildew disease

Powdery mildew mainly affects leaves, but also flowers, fruits, fruit stems and petioles. In the early stage, lesions of different sizes were produced at the diseased center of the diseased leaves, and then white powdery substances formed on the back of the leaves. When the disease is serious, in addition to leaves, petioles, flowers, pedicels and fruits can be susceptible to the disease, resulting in leaf margin atrophy and scorch. Young fruits stop developing and even dry up. A white powder forms on the fruit and loses its edible value. In more severe cases, the entire plant will die.

1.2 Powdery mildew disease preventive measures

1.2.1 Select disease-resistant varieties or plant varieties with stronger resistance.

1.2.2 Implement crop rotation, preferably cruciferous vegetables and leguminous crops, preferably flood and drought rotation.

1.2.3 Remove diseased leaves, diseased fruits and old leaves in time during the growth period, and take them out of the shed for deep burial.

1.2.4 High temperature disinfection of soil is required from July to August.

2. Grey mildew disease

2.1 Causes and hazards of grey mildew disease

Grey mildew is the main disease after flowering, which mainly damages flowers, fruits and leaves. In the early stage of flower damage, water-soaked dots appear on the calyx, which gradually expand to damage the ovary and fruit, causing the fruit to rot. After the fruit is damaged, light brown lesions are formed and develop into the fruit, making the fruit wet and easy to fall off. When the humidity is high, gray-brown mildew can be produced, and when it is dry, the diseased fruit is dry and rotted.

2.2 Grey mildew disease preventive measures

Deep plowing before planting, cultivation on high borders, and pay attention to dehumidification and warming throughout the growing season.

3. White leaf spot disease

3.1 Causes and hazards of white leaf spot disease

White leaf spot disease mainly occurs on the leaves, especially after the fruit is harvested. The diseased leaves produce small dark purple-red spots at the beginning, and then expand into circular or oval lesions of 2-5 mm in size, with purple-red edges, gray-white centers, and slightly thin circles, making the entire lesions in the shape of snake eyes. Excessive leaf disease spots will cause the leaves to dry out, and a large number of disease spots will affect the photosynthesis of the leaves and reduce the disease resistance of the plants.

3.2 White leaf spot disease preventive measures

3.2.1 Thoroughly clean up the field and burn or bury the dead leaves.

3.2.2 Remove diseased leaves as soon as possible, and cut leaves in the whole garden after the fruit is harvested in the plots with severe disease.

3.3.3 Weeding, fertilizing, and watering in cultivating to promote early growth of new leaves.

4. Root rot disease

4.1 Causes and hazards of root rot disease

Strawberry root rot disease, also known as red heart disease or brown heart disease, mainly damages the roots. It starts from small lateral roots or new roots, and initially appears light reddish-brown irregular plaques, which gradually becomes darker brown. With the development of the disease, all the roots rapidly necrotic and turn brown. The aerial part of the outer leaf first turned yellow, browned, necrotic to curl, and the diseased plant was deficient in water, and gradually developed to the central leaf until the whole plant withered and died.

4.2 Root rot disease preventive measures

4.2.1 Rotate crops, preferably with cruciferous and lily vegetables.

4.2.2 Apply fully decomposed organic fertilizer to reduce root damage.

4.2.3 Thoroughly sterilize the soil or treat with high temperature before transplanting, and do not plant diseased seedlings. When transplanting seedlings, soak the roots of the seedlings with captan.

4.2.4 Clean the garden, remove the diseased plants in time, take them out of the field for destruction, and apply a small amount of lime after removing the diseased plants.

4.2.5 Apply more organic fertilizer and less nitrogen fertilizer to cultivate strong seedlings.

4.2.6 Prevent flood irrigation and avoid water accumulation caused by watering.

5. Verticillium wilt disease

5.1 Causes and hazards of Verticillium wilt disease

Verticillium wilt disease is a soil disease. The main symptoms are deformity of young leaves, yellowing of leaves, and rough surface of leaves. The leaf margins then turn brown and wither inward until they die.

5.2 Verticillium wilt disease preventive measures

5.2.1 Avoid continuous cropping, and it is strictly forbidden to select and keep special mother plants for reproduction in the diseased strawberry garden.

5.2.2 If the diseased plants are found, they should be removed in time, and they should be removed together with the seedlings in the nursery garden.

5.2.3 Before transplanting, use solar energy to sterilize the soil at high temperature. When the soil temperature reaches 60℃, it can kill germs.

6. Brown blotch disease

6.1 Causes and hazards of brown blotch disease

Brown spot disease mainly affects leaves, fruit stems and petioles can also be diseased. After the leaves were infected, brown spots appeared first, and then gradually expanded into round or nearly oval spots. The center of the round spots was brown, the periphery was purple-brown, and the edges were purple-red. In the later stage, small brown spots can be formed on the lesions, which are arranged in irregular circles. When the lesions fuse together, large swathes of leaf tissue can die. When lesions occur on leaf tips and leaf veins, leaf tissue is often withered in a "V" shape.

6.2 Brown blotch disease preventive measures

Select disease-resistant varieties, cultivate strong seedlings, and control the amount of nitrogen fertilizer used.

7. Bud blight disease

7.1 Causes and hazards of bud blight disease

The young buds of the diseased plants are wilt-like, and the leaves and sepals form brown spots, which gradually wither. The base of petioles and fruit stalks turn dark brown, the leaves lose their vitality, wilting and drooping. When acutely ill, strawberry plants will be cataplexy, and without control, it will spread quickly and cause serious losses.

7.2 Bud blight disease preventive measures

7.2.1 Try to avoid raising seedlings and planting strawberries in areas where bud blight disease occurs, otherwise soil disinfection by solar must be used.

7.2.2 Appropriately sparsely plant, irrigate reasonably, ensure ventilation, and reduce environmental humidity.

7.2.3 It is necessary to ventilate in a timely manner, and quickly ventilate after irrigation to reduce indoor humidity.

7.2.4 Remove diseased plants in time, and it is strictly forbidden to use diseased plants as mother plants to propagate strawberry seedlings.

8. Anthracnose disease

8.1 Causes and hazards of anthracnose disease

Anthracnose disease mainly damages stolons and petioles, leaves, stipules, flowers, fruits and rhizomes. In the early stage of the disease, the lesions were water-soaked state, spindle-shaped or oval in shape, and later the lesions became black, or black in the center and reddish brown at the edges. The lesions on leaves and stolons were relatively regular and tidy, and the lesions on stolons and petioles could expand into a ring, and the upper part wilted and died. When the relative humidity is high, pink jelly (conidia heap) can be seen in the lesions. When the whole plant withered, brownish red or brownish browning from the outside to the inside could be seen on the cross section of the rhizome, but the vascular bundles remained unchanged.

8.2 Anthracnose disease preventive measures

8.2.1 Select varieties with strong disease resistance and avoid continuous cropping, which can be rotated with rice.

8.2.2 Shade and cool down during high temperature period.

8.2.3 The diseased plants should be removed in time at the first sight, the diseased plant pit should be disinfected with quicklime water, and the removed objects should be taken out of the shed and burned or buried deep to reduce the spread.