Control greenhouse strawberry powdery mildew
With the increasing area of ​​strawberry in the greenhouse, the occurrence of powdery mildew is advanced, the degree of disease is aggravated, and the area is increased. The strawberry powdery mildew in the greenhouse mainly occurs after the shed, and the seedlings mainly infect the leaves, and the flower and fruit stage mainly infects the flowers and fruits. In the early stage of the disease, there is a sparse white mold layer on the back of the leaf. As the disease worsens, the mildew layer thickens to form a dense white round spot. In severe cases, the leaves are wound up and infected with petioles, fruit stems, leaves, reddish brown lesions, and leaf margins atrophy. Dry. After January, the strawberry enters the flowering stage. After the flower is infected, it turns from white to pink. After the disease, the young fruit can not expand normally and dry and wilting; the result of the disease has a layer of white hair, the coloration is slow and uneven, and the fruit loses its luster. Hardening stops growing; seriously affecting the commodity and edible value of strawberries. Therefore, the following measures must be taken in the prevention and control:
Choose resistant varieties, cultivate robust and sterile strawberry seedlings, and control the occurrence of pathogens.
The applied organic fertilizer should be decomposed, the compound fertilizer should be appropriate, especially the nitrogen fertilizer can not be applied too much, prevent the burning of seedlings and prosperous; timely watering, control soil moisture, greenhouse humidity, meet the water requirement of strawberry flowering period; reasonable cultivation Density can increase the ventilation and light transmission of greenhouse strawberries; timely removal of old leaves, diseased leaves, and diseased fruits.
The greenhouse continuous strawberry cultivation can eliminate the pathogens in the soil and diseased bodies by using high temperature shacking technology, and comprehensively control a variety of soil-borne diseases and other diseases of strawberries.
In the production of susceptible varieties such as Hongyan, Hongxia, etc., before the flowering, no protective fungicides for active prevention, with 1 × 106 spores / gram of Pythium oxysporum WP 3,000 times spray, 2% Wuyi 200 times spray of mycorrhizal water, 400 times spray of 4% agricultural anti-120 water agent, 600 times spray of 75% chlorothalonil wettable powder, spray once every 7-14 days, the effect of alternating drug use is better.
After the onset, it is necessary to use a protective and therapeutic agent for prevention and treatment, using 3000% spray of 50% ether oxystrobin water dispersing granules, 1000 times spraying of 4% tetrafluoroetherazole water, and 10% difenoconazole water dispersing granules. 1500 times spray, spray once every 7-10 days, the effect of alternating agents is better.
When the greenhouse humidity is high, 50 m × 8 m sheds are used for 4 sheds of 2% oxytetracycline smog, or 4% of 20% chlorothalonil smog. Sulfur fumigation device fumigation, each time with 99.5% sulfur powder 20 grams, fumigation 2 hours per day during the prophylaxis period, fumigation 8 hours per day during the onset period, 7-10 times after continuous use to restore the use period; the use of fumigation drugs alternately.
Issues to pay special attention to:
The focus of strawberry powdery mildew is prevention, and the prevention and treatment effect is limited after severe disease.
Azole drugs are commonly used drugs for controlling strawberry powdery mildew in greenhouse. If the dosage is too large or used several times, it will inhibit the growth of strawberries.
Spray any medicines to avoid the flowering period and avoid berries and deformed fruits.
Frequent use of large amounts of chemicals can also cause abnormal fruit disease to contaminate the fruit.
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