Disease Prevention and Control Measures and Technical Key Points for Greenhouse Strawberries
Strawberry leaf blight mainly affects leaves, petioles, fruit stalks and calyxes. 1. Symptoms. In the early stage of the disease, small dull dark purplish-brown spots appear on the leaves, which then expand into irregular lesions; the color of the lesion edges and centers changes little, and the symptoms of this disease are difficult to distinguish from those of brown spot disease in its early stage. Brown spot disease and leaf blight...
1. Preventive measures: deep furrows and high beds, with full-bed plastic film mulching; generally the furrows are 30-40 cm deep, and the plastic film should be brought down to near the bottom of the furrows to reduce fruit contact with the soil and thus disease incidence, and improve drainage to reduce damage. Remove dead leaves and diseased leaves promptly.Increase the application of organic fertilizer, especially the biological fertilizer "Tudele", to improve the soil. Apply nitrogen, phosphorus and potassium in appropriate amounts and in balance, control the amount of nitrogen fertilizer to prevent excessive vegetative growth, and at the same time plant at a reasonable density, with the number of plants per mu controlled within 8,000 to facilitate ventilation and light penetration. Supplement trace elements appropriately to improve disease resistance. When young leaves begin to grow and at the bud stage, spray quick-acting boron, copper sulfate and manganese sulfate, etc. During the growing period, spray the marine biological immune preparation Haitianli at 600 times dilution once every 7-10 days for 3-4 consecutive applications to enhance the disease resistance of strawberries.
2. Chemical control: the principle is a control method combining biological plus chemical agents, and internal resistance plus external suppression.
For powdery mildew, 25% triadimefon wettable powder at 3000-5000 times + Haitianli at 600 times, or 10% difenoconazole water-dispersible granules at 2000-2500 times + Haitianli at 600 times, or 12.5% myclobutanil emulsifiable concentrate at 1500 times, applied alternately with fungicides.
For gray mold, during the growing period (avoiding the flowering period), spray polyoxin wettable powder at 500 times + Shibike at 600 times, or 50% pyrimethanil at 600 times; be sure to alternate the products used.