Kiwifruit, whose taste is described as a mixture of strawberry, banana and pineapple. In addition to organic substances such as actinidin, proteolytic enzymes, tannin pectin and sugars, as well as trace elements such as calcium, potassium, selenium, zinc, germanium and 17 kinds of amino acids required by the human body, kiwifruit also contains rich vitamin C, gluconic acid, fructose, citric acid, malic acid and fat.
1. Kiwifruit canker
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Damage symptoms
Trunk and branches affected: cortical tissue is water-soaked, softened and slightly raised. In the early stage of the disease, filamentous mucus is leached, and then turns into bluish-white to dark red sap flowing out.
Leaf infection: small chlorotic spots appear on new leaves, which are water-soaked and then develop into irregular or polygonal brown spots. There is a wide yellow halo around the lesions, and sometimes no yellow halo is produced.
Buds affected: They cannot open, turn brown and die, and then fall off. Although the buds with mild damage can open, they open slowly or cannot open completely. Such flowers may fall off or set fruit, but the fruit formed is small and easy to fall off or become deformed.
Prevention and control methods
① Strengthen the inspection of seedlings, and strictly prohibit the transportation of seedlings, scions and cuttings from the diseased area to prevent long-distance transmission.
② In winter, burn the dead branches and fallen leaves with pathogens in a centralized manner, and remove diseased and insect-infested branches, diseased leaves, long branches, drooping branches, etc. in early spring in combination with pruning to reduce the source of infectious diseases.
③ Spray the leaves with 400-600 times of chloranil wettable powder in mid-September of the previous year. After winter pruning, spray 3-4 degrees Baume lime sulfur mixture in time. Spray 3-5 degrees Baume lime sulfur mixture or 1000 times of streptomycin solution on the whole garden before germination.
2. Kiwi brown spot disease
Harm symptoms
The disease mainly harms the leaves of kiwifruit. During the shoot and bud stage, the disease starts from the leaf edge.
In the early stage of the disease, nearly circular dark green water-soaked spots are mostly produced on the edges of the leaves. Under rainy and humid conditions, the spots expand rapidly to form large nearly circular or irregular spots.
In the later stage, the center of the spots is brown, the surrounding is gray-brown or gray-brown, the edges are dark brown, and many black dots appear on them. The affected leaves curl and crack, dry and fall off easily.
Prevention and control methods
① Strengthen fertilizer and water management to enhance tree vigor.
② In the early stage of the disease, spray 1000 times of 70% methyl thiophanate wettable powder, 1000 times of 80% mancozeb wettable powder, 2000 times of 25% azoxystrobin suspension, or 1500-2000 times of 10% difenoconazole water dispersible granules, spray once every 7-10 days for 3 times in a row.
3. Kiwi Anthracnose
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Damage symptoms
When the leaves are infected, they usually open from the edge of the leaves, initially appearing water-soaked, and then turning into thirsty irregular lesions, with obvious boundaries between the diseased and healthy parts; the lesions turn grayish white in the middle and dark thirsty on the edges in the later stage. The edges of the affected leaves curl, and the leaves are easy to break when dry, and many small black spots are scattered on the front of the lesions.
When the fruit is infected, in the early stage of the disease, small light brown spots the size of a needle head appear on the green fruit surface, which are round and have clear edges; in the later stage of the disease, the white spots gradually expand and turn into brown or dark brown. The surface is slightly concave. When cut longitudinally from the diseased part, the flesh of the diseased fruit turns brown and rots, and can rot to the core of the fruit.
Prevention and control methods
① Reasonable pruning to make the orchard ventilated and light-permeable, and reasonable application of nitrogen, phosphorus and potassium fertilizers to improve the disease resistance of the plants. Pay attention to drainage after rain to prevent water accumulation. Clean the orchard after picking fruits, cut off diseased and insect-infested branches and dead branches, and burn them in a centralized manner to reduce the source of disease and insect infection.
② Before germination, spray the whole orchard with 5 degrees Baume lime sulfur mixture once. After the flowers fade and before bagging, spray 25% prochloraz emulsifiable concentrate 800~1500 times, or 25% azoxystrobin suspension 1000~1500 times, or 50% carbendazim wettable powder 600 times, or 70% methyl thiophanate wettable powder 800~1000 times for prevention and control.
4. Kiwi mildew
Damage symptoms
Mainly harm the fruit, but also harm the branches and leaves. The affected area is dirty brown, green, dirty black irregular or strip-shaped stains, which occur on the fruit and seriously reduce the value of the fruit.
Prevention and control methods
① Improve the ventilation and light conditions of the orchard, reduce the humidity of the orchard, and apply nitrogen, phosphorus and potassium fertilizers reasonably; bag the young fruit.
② When the disease occurs, 70% thiophanate wettable powder 1000 times solution, or 25% carbendazim wettable powder 500 times solution can be used, spray once every 10 days, and spray 4 times in a row.
5. Kiwifruit Armillaria root rot
Harmful symptoms
The disease causes yellow-brown block spots to appear on the cortex of the root neck at first, and the cortex gradually turns black and soft. The phloem is easy to fall off, the woody body turns brown and rots, and there is a smell of wine lees. When the soil humidity is high, the lesions expand rapidly and gradually spread downward, causing the entire root system to turn black and rot, and a lot of brown juice flows out of the diseased part, the woody body turns light yellow, the leaves quickly turn yellow and fall off, and the tree wilts and dies.
Prevention and control methods
① During the rainy season, dig trenches for drainage, plant not too deep, and apply fully decomposed organic fertilizer. The garden should be selected on sandy soil with good permeability.
② For tree tray application, 60% mancozeb 0.5kg can be added with water and then 200kg can be used for root irrigation, or 58% metalaxyl. Mancozeb wettable powder 500 times diluted can be used for root irrigation prevention and control.
6. Kiwi blight
Harm symptoms
Mainly harm the root system, manifested as sudden wilting of the plant and death in the same year.
The disease-resistant varieties are mostly infected from the root tip, gradually expanding upward, the aboveground buds are late, the leaves are weak, and the fruit is poorly developed;
The susceptible varieties start from the root neck or main and lateral roots, the affected parts are ring-shaped brown wet rot, and the diseased parts grow flocculent white mold. The plant turns green and withered in a short period of time, and the disease spreads very quickly.
Prevention and control methods
①Strengthen management and be careful when cultivating to avoid wounds. Use formula fertilization technology, and avoid excessive nitrogen fertilizer. Drain water in time after rain to prevent moisture retention. Dig out diseased seedlings in time, and then sprinkle quicklime on the diseased holes for disinfection.
② Seedling treatment: soak the base of the seedlings with 500 times of 25% metalaxyl wettable powder or 500 times of 61% phosphine. manganese zinc wettable powder for 10-15 minutes, and plant after drying.
③ In the early stage of the disease, spray 600 times of 72% cymoxanil. manganese zinc wettable powder, 700 times of 69% oxadiazine. manganese zinc wettable powder, or 600-800 times of 18.7% oxadiazine. pyraclostrobin water dispersible granules for prevention and control.
