Key Pest and Disease Control Measures Before and After Grape Flowering!

I. Key Points for Pre-Flowering Pest and Disease Control:

1. Brown rachis necrosis, downy mildew, and gray mold: These diseases affect the fruit stalks, stems, and berries before and after flowering, causing lesions, brown necrosis, and the production of gray mold (gray mold), white mycelium and mold (downy mildew), and brown spores (brown rachis necrosis), leading to inflorescence drop, berry drop, and even bunch drop. Black rot affects tender shoots, buds, leaves, and young fruit, producing brown oval lesions with a white depression in the center, reducing fruit quality and yield. Powdery mildew affects leaves, stems, and young fruit. The affected areas show a white powdery substance; after healing, light brown lesion spots and mold appear.

2. Green stink bugs and scarab beetles affect tender buds, leaves, and young fruit. They form small, irregular brown spots on the fruit surface; as the fruit grows, these spots enlarge, dry, and form scabs. Leafhoppers damage leaves by sucking sap, affecting leaf function. Spider mites damage leaves, stems, and fruit stalks, causing leaf curling and irregular brown lesions on stems and fruit stalks.
Pre-flowering pest and disease control is crucial for grapes; pesticides cannot be applied during peak flowering as this affects pollination and fruit set. Therefore, 2-3 days before flowering is the critical period for pest and disease control.
Control plan: It is recommended to apply a mixture of 45% azoxystrobin-thiophanate-methyl at 1500x dilution + 40% fludioxonil at 4000x dilution + chlorpyrifos at 1000x dilution 2-3 days before flowering for pest prevention. For orchards with spider mite infestations, add abamectin at 2000x dilution for control. Azoxystrobin-thiophanate-methyl is a broad-spectrum, highly effective pesticide with both protective and curative effects, controlling various fungal diseases, and showing good control of rachis rot, downy mildew, gray mold, black rot, and powdery mildew.

For orchards with downy mildew, spray with a 1000-fold dilution of 48% dimethoate-cymoxanil. For rachis rot and black rot, spray with a 1000-fold dilution of 40% difenoconazole. For gray mold, spray with a 3000-fold dilution of 40% fludioxonil. For powdery mildew, spray with a 1000-fold dilution of 30% azoxystrobin-ethirimol.

II. Key Points for Post-Flowering Pest and Disease Control:

The period after flowering is the most critical time for pest and disease control in greenhouse-grown grapes. During the flowering period of greenhouse-grown grapes, the uncontrollable temperature, vigorous vine growth, relatively high humidity, and poor ventilation create an environment conducive to the occurrence and damage of pests and diseases. Grape flowering requires a large amount of nutrition, which is concentrated on flowering, fruit setting, and the formation and expansion of young fruit, leaving the tree nutrient-poor and vulnerable to disease. The incidence of disease after flowering is higher than at other phenological stages.
After flowering, rachis rot and downy mildew mainly damage the fruit stalk, stem, and berries. Powdery mildew, black rot, and gray mold damage leaves, stems, and fruit clusters. Meanwhile, green stink bugs, leafhoppers, scarab beetles, and spider mites also damage branches, leaves, and fruit clusters. This causes rachis rot, fruit stalk mold, blackening and drying of berries, fruit drop, or wounds and mottling caused by insect infestations, affecting yield, quality, and profitability. Therefore, pest and disease control after grape flowering is crucial.

After flowering, the following agricultural practices should be observed:
1. Appropriately regulate the greenhouse temperature: 26-28℃ during the day and 14-16℃ at night, with relative humidity controlled at 60-70% to reduce pest and disease damage
. 2. Timely cultivation and loosening of the soil to increase soil temperature; top dressing with 1 bag of Jiaming Hongli + 2-3 kg of Jiaming Hailibao per acre to promote root growth and nutrient absorption, cultivate strong trees, and improve disease resistance.
3. Timely ventilation to reduce humidity inside the greenhouse and create an environment unfavorable to disease occurrence.
4. Upon discovering disease, promptly remove diseased branches, leaves, and spikelets, and remove them from the orchard for centralized disposal and destruction.
5. Employ chemical control to reduce pest and disease damage.

The first application of pesticides after flower fall, when 80% of the flowers have fallen, is more effective when using a mixture of protectants and curatives. It is recommended to use a mixture of 40% fludioxonil (3000x dilution) + 35% pyraclostrobin (1500x dilution) + 40% dimethomorph (1000x dilution) + 15% chlorpyrifos (1000x dilution) + Jiaming Brain Platinum (1000x dilution) for uniform spraying.
The second application, 10-15 days after the first, should primarily use eradicants, such as 45% azoxystrobin (1500x dilution) + 40% fludioxonil (3000x dilution) + 48% dimethomorph (1500x dilution) + 35% thifluzamide (2000x dilution) + 5% abamectin (3000x dilution) + Jiaming Brain Platinum (1000x dilution) for spraying. In orchards where powdery mildew has occurred, simply replace 45% azoxystrobin with 30% azoxystrobin and ethyl phenol at a 1000-fold dilution for spraying.
After flowering and during the young fruit stage, pay special attention to the following when applying pesticides:
1. Do not use pesticides if the greenhouse temperature exceeds 30℃; avoid spraying pesticides at high temperatures.
2. Spray from bottom to top, onto the underside of the leaves, ensuring even and thorough coverage without dripping.
3. Use a sprayer with good atomization, sufficient pressure, small nozzles, and meticulous application.