Key Technical Points for the Prevention and Control of Apple Pests and Diseases in the Mid-to-Late Stage

The young fruit stage is the peak infection period of early defoliation disease, the initial stage of branch ring rot, and also the peak damage period of aphids, leaf mites and scale insects. Therefore, doing a good job in the prevention and control of apple pests and diseases during the young fruit stage is crucial for strengthening tree vigor, improving fruit quality and achieving increased yield and income.

I. Forecast of the mid-to-late stage trends of apple pests and diseases

According to meteorological forecasts, rainfall from June to August will be higher than in previous years, which is conducive to the infection of fruit tree diseases but unfavorable to the occurrence and damage of insect pests. Based on comprehensive analysis of the current pest and disease occurrence and weather forecasts, it is predicted that pests and diseases in the mid-to-late stage will show a moderate occurrence trend, among which apple early defoliation disease and powdery mildew will occur moderately, ring rot, anthracnose and rust will occur lightly, and hawthorn spider mite, apple leaf roller, aphid, scale insect, golden-striped leaf miner and peach fruit borer will occur lightly.

II. Prevention and control measures

1. Agricultural control: combined with summer pruning, improve ventilation and light conditions in the orchard, apply fertilizer scientifically, plant white clover, promptly detect and remove infected parts or insect bodies such as diseased branches, shoots and fruits, and burn or bury them deep outside the orchard.

2. Chemical control

(1) For chemical control of diseases, fungicides should have both protective and therapeutic effects. Protective agents include 75% mancozeb water-dispersible granules and 75% chlorothalonil wettable powder; systemic therapeutic agents include 10% difenoconazole water-dispersible granules or suspension concentrate, 10% polyoxin wettable powder and 70% thiophanate-methyl wettable powder. Choose one protective agent and one therapeutic agent.

(2) For chemical control of insect pests, according to the types and severity of insect pests in the orchard, select the appropriate insecticide from any one of 2.5% beta-cyhalothrin emulsion in water, 5% emamectin benzoate water-dispersible granules, 25% diflubenzuron suspension concentrate, 20% triflumuron suspension concentrate, 48% chlorpyrifos emulsifiable concentrate, 5% fenpyroximate suspension concentrate and 50% clofentezine suspension concentrate.

(3) The young fruit stage is a key period for calcium absorption. At this time, supplement calcium appropriately to promote the growth of young fruits.

3. Physical control

Install solar insect-killing lamps or frequency-vibration insect-killing lamps, and hang yellow sticky boards and sex pheromone lures.

III. Precautions

1. Disease control must focus on prevention, and prevention should be carried out before disease appears; for insect pest control, the timing of control must be well grasped.

2. For the control of ring rot fruit rot, the period before wheat harvest is critical, and spraying must be timely and thorough.

3. In disease control, special attention should be paid to the relationship between rainfall and disease occurrence, and spraying should be carried out promptly in conjunction with rainfall, preferably after rain.

4. Avoid high temperatures when spraying, use pesticides alternately as much as possible, follow the instructions, and do not arbitrarily increase the dosage, so as to reduce or avoid pesticide damage and resistance.