What is the disease that half the leaves of strawberry bud and receptacle are burnt?
5. Strawberry powdery mildew
Strawberry powdery mildew mainly occurs in strawberry producing areas in northern China, which is a common disease in strawberry growing areas, especially in protected cultivation. Under suitable conditions, it can develop rapidly, flood and cause serious losses.
symptom
grass
Strawberry powdery mildew mainly attacks leaves, tender shoots, fruits and fruit stalks; Petiole and stolon are rarely injured. In the early stage of leaf disease, a thin layer of white mycelium grows on the leaf surface, and then it quickly expands to the whole plant. With the aggravation of the disease, the leaf margin gradually
The leaves are rolled into spoons, and dark stains and white powder of different sizes appear on the leaves. In the later stage, it showed reddish-brown lesions, the leaf margin shrank and withered, the bud was damaged, and the young fruit could not expand and dry normally. If you suffer later, the surface of the fruit is covered.
A layer of white powder, the fruit stops hypertrophy, loses luster and hardens, and the coloring is slow, which loses commercial value and seriously affects the quality of berries.
Occurrence characteristics
The pathogen of strawberry powdery mildew is ascomycetes and powdery mildew.
Powdery mildew family, Powdery mildew order.
Single capsule period of Leymus chinensis. The pathogen of strawberry powdery mildew in northern China is closed capsule shell, mycelium and so on.
Overwintering on the ground or living old strawberry leaves. Strawberry powdery mildew is an obligate parasitic fungus. Powdery mildew mainly relies on propagation materials such as diseased strawberry seedlings for long-distance transmission, and the climate is conducive to the spread of pathogen spores in the field.
Spread. Conidia or ascospores are produced in the following spring and spread to the host leaves by airflow. The bud tube and haustorium produced at the top of conidia invade from the epidermis of leaves, and hyphae attach to leaves. It usually takes more than 20 minutes from germination to invasion.
3-5 hyphae can grow every day, and after 5 days, white hyphae cluster lesions will form at the infected site. After 7 days of maturation, conidia spread and re-infected. The optimum temperature for pathogen infection is 15—
20oC, lower than 5oC and higher than 35oC can not cause disease, but pathogenic spores can not germinate in the presence of water droplets. Protected cultivation is prone to disease, and there are differences in disease resistance among varieties.
Prevention and cure method
1. Select resistant varieties, such as Baojiao Zaosheng, Hani, All-Star and other varieties with strong resistance to powdery mildew.
2. Clean the garden in winter and spring, burn rotten branches and leaves, remove sick and old leaves in time, and bury them deeply in the growing season. Planting should not be too dense, strengthen fertilizer and water management, apply fertilizer reasonably, prevent partial application of nitrogen fertilizer, control humidity, and make plants ventilated and transparent and grow healthily. Drainage in time after rain.
3. Medicine
Agent control. Spray 27% high-fat film emulsion 80- 100 times, 5-6 days 1 times, 3-4 times in a row. Or 600-700 times or 70% of 50% carbendazim wettable powder.
1000 times of thiophanate methyl wettable powder, or 2500-4000 times of mirex wettable powder, or 10% of segao wettable powder, or 2000 times of 12.5% of myclobutanil EC.
Liquid. 7- 10 day 1 time. When spraying, apply the medicine evenly between the back of the leaf and the bud seam. However, it should be noted that spraying acaricide wettable powder at high temperature sometimes causes phytotoxicity, so it is best to reduce the concentration of the liquid medicine when using it. protect
Protected cultivation can be disinfected with 0.2-0.25 kg/mu of 45% chlorothalonil fumigant or quick-curing fumigant. Generally, the drug should be stopped 7 days before harvest.
6, strawberry gray mold
Strawberry gray mold is the main disease of strawberry cultivation in open field and protected field, which is widely distributed. Rotten fruit caused by gray mold can generally reduce the yield 10%-30%, and serious fruit can reach more than 50%. In addition to damaging strawberries, it can also harm vegetables such as tomatoes, peppers, lettuce, eggplant and cucumbers, and plants such as flowers and fruit trees are also seriously damaged.
symptom
exist
Strawberries are mainly harmful to fruits, and leaves, petioles, petals, calyx and fruit stalks can all be infected. When it occurs on leaves, brown or dark brown water stains are produced at the affected area, and sometimes there are micro-wheel marks at the affected area. When it is dry, it is brown, dry and humid.
Milky white fluffy hyphae appeared on the back of leaves. Buds and pedicels turn dark brown and then spread to death, extending from calyx to ovary and young fruit. When the fruit is killed, oily light brown spots appear on the damaged part at first, and enter
But the spots spread to the brown spots on the edge and the dark brown spots in the center, and there are obvious oil stains around the spots. Finally, the whole fruit becomes soft, and the diseased part is densely covered with gray mold, which is the conidia and conidia of pathogenic bacteria, and the onset time is long when the humidity is high.
White flocculent hyphae are produced. In addition, the pathogen can also form flat or irregular black rat dung-like sclerotia on the damaged plants.
Occurrence characteristics
Strawberry botrytis cinerea belongs to botrytis cinerea.
Botrytis cinerea Pathogens overwinter in damaged plant tissues in the form of hyphae, sclerotia and conidia at a temperature of 18-20oC.
At high temperature, bacteria multiply and spores spread through the air. When the temperature is about 20oC, the rain is continuous, the planting is too dense, the nitrogen fertilizer is too much, the ventilation and light transmission of the plants are poor or the humidity is too high. Especially in promoting and semi-
Under the condition of promoting cultivation, the leaves are fertile, densely planted and the lower leaves are not removed, but when the leafy plants are closed and the rain humidity is too high, the diseases will occur quickly. In addition, continuous cropping fields, continuous cropping fields and susceptible varieties are seriously ill.
Prevention and cure method
1, control fertilization, planting density and field humidity, and implement plastic film mulching to prevent fruits from contacting soil. Select hard fruit disease-resistant varieties, remove old, sick, residual leaves and susceptible inflorescences in time, and remove diseased fruits.
2. Pay attention to crop rotation, cultivate deeply before planting, advocate high ridge cultivation, treat the soil with chemical agents, sprinkle 75-90 kg of 25% carbendazim wettable powder per hectare before planting, and rake it into the soil to prevent diseases. Protected cultivation can be disinfected with 45% chlorothalonil fumigant 3-3.75 kg/ha or quick-acting fumigant.
3. Medicine
Agent control. In order to prevent it, the best time to use medicine is when the first inflorescence of strawberry blooms more than 20% and the second inflorescence just blooms. 300 times solution of 25% carbendazim wettable powder and bacteriostatic wettable powder can be selected.
500-800 times solution, 800 times solution of 50% Kelidan wettable powder, 600 times solution of Dijunling wettable powder, etc. , every 10 day 1 time until a large number of fruits are harvested. You can also spray 50% Sukeling wettable powder.
800 times powder, 1000 times 50% chlorpheniramine wettable powder, 400-600 times 70% zineb wettable powder, or 500 times 65% zineb wettable powder before flowering.