Detailed Explanation of the Pollution-Free Annual Management Calendar for Plums

November-February ?? Dormant Period

1. Training: The natural open-center shape is commonly used, with the trunk heading height at about 60 cm; thereafter, select and retain 3-4 vigorous, similarly growing new shoots on the upper part to train as main branches. During winter pruning, cut back the main branches at a plump bud, leaving an outward-facing bud at the cut; the angle between the main branches and the trunk is 50°-60°, and 2-4 sub-main branches are trained on each main branch.

2. Pruning: Plum trees bear fruit mainly on bouquet spurs (short fruiting branches), so pruning often uses long canes and branch thinning to promote short branch formation; for weak and drooping branches, use renewal pruning to rejuvenate them; mainly thin out diseased and pest-infested branches, overly dense branches, upright water sprouts on the upper side of branches, and crossing branches.

3. Orchard sanitation: Clear weeds from the orchard and bury them deep as organic fertilizer; gather the diseased and pest-infested branches left after pruning and burn them; then spray the canopy 1-2 times with 5 degrees Baumé lime sulfur mixture; in early February or at the flower bud stage, spray 1-2 times with 1:1:100 Bordeaux mixture.

March ???? Bud Break and Blooming Period

1. Preserving flowers and fruit: (1) Artificial pollination: used for varieties lacking pollen and in years with poor weather during the flowering period; collect pollen, air-dry it naturally, mix it with 3-4 times its volume of starch or talcum powder, and apply it to the stigmas at full bloom; pollinate 2-3 flowers per short fruiting branch, and it is sufficient to pollinate 1/3-1/2 of the short fruiting branches. (2) Keeping honeybees: (3) Spraying micronutrient fertilizers: spray 2-3 times with a mixture of 0.3% borax plus 0.3-0.5% urea plus 0.3% monopotassium phosphate.

2. Flower and fruit thinning: (1) Artificial flower and fruit thinning: artificially thin out half of the flowers; (2) at full bloom, spray 150 ppm ethephon or 0.5 degrees Baumé lime sulfur mixture.

3. Fertilization: For weak trees and those bearing many fruits, apply a certain amount of supplementary fertilizer, using nitrogen and potassium fertilizers combined with quick-acting organic fertilizer.

4. Main pest and disease control: The main insect pests include: plum sawfly, flower thrips, weevils, stink bugs, aphids, and other leaf-eating insects, controlled with insecticides. The main diseases include: plum red spot disease, scab, brown rot, shot hole disease, and plum pocket disease, controlled with various fungicides for early prevention. During this period, take care to mix contact-type wettable powder insecticides with fine soil, spread it on the tree basin, and shallowly turn it with a hoe to kill overwintering insects in the soil.

April Pit Hardening and Shoot Growth Period

1. Spraying foliar fertilizer: apply once every 10-15 days a mixture of 0.2-0.3% borax plus 0.3% monopotassium phosphate plus 0.4-0.5% urea.

2. Fruit thinning: To control alternate bearing and improve fruit grade, fruit thinning must be carried out. Leave 1-2 fruits on short fruiting branches, 3-4 on medium fruiting branches, and 5-7 on long fruiting branches. Thin out diseased and pest-damaged fruits, small fruits, deformed fruits, twin fruits, and overly dense fruits.

3. Applying fruit-swelling fertilizer: Mainly nitrogen and potassium fertilizers, combined with quick-acting organic fertilizer, accounting for 20-30% of the annual amount.

4. Pest and disease control: The main insect pests include: plum fruit moth, apricot star moth, plum sawfly, leafhoppers, weevils, aphids, scale insects, etc., which can be controlled with broad-spectrum insecticides. The main diseases include: plum red spot disease, scab, brown rot, shot hole disease, plum pocket disease, etc., controlled with fungicides.

May Fruit Development and Branch and Shoot Growth Period

1. Summer pruning: Use methods such as pinching, twisting branches, wounding by bending, bending branches, and propping branches to help with training and regulate tree vigor.

2. Fruit thinning: Carry out further fruit thinning on trees that were not thoroughly thinned last month and are bearing too many fruits.

3. Pest and disease control: The main pests and diseases are the same as in April; control them in a timely manner according to pest and disease occurrence.

June-August Fruit Ripening Period

1. Applying post-harvest fertilizer: Apply nitrogen and potassium fertilizers combined with quick-acting organic fertilizer, accounting for 20-30% of the annual total. For late-maturing varieties, fertilizer can be applied before harvest to promote flower bud differentiation.

2. Pest and disease control: This period is the fruit ripening period, and generally no pesticides of any kind can be used within 10-20 days before fruit harvest. After fruit harvest, pesticides can be applied at the appropriate time in orchards with relatively severe pest and disease problems. Alternatively, remove diseased fruits, diseased branches and leaves, etc., and burn them in a centralized manner, and capture and kill longhorn beetles, etc.

September-October Leaf Fall Period

1. Applying base fertilizer: Base fertilizer should be applied early in autumn, mainly organic fertilizer, combined with nitrogen, phosphorus, and potassium fertilizers. Nitrogen and potassium fertilizers account for about 70% of the annual amount, and all phosphorus fertilizer is applied.

2. Plowing the orchard soil and interplanting green manure crops.

Appendix:

1. Names and application concentrations of main fungicides: (1) Xiansheng: 600 times dilution (a fungicidal formulation, spray first); (2) Dasheng: 600-800 times dilution (a protective formulation, spray 7-10 days after using Dasheng); (3) 65% mancozeb: 500-800 times dilution; (4) Lime sulfur mixture: use 5 degrees Baumé in winter, 0.5 degrees Baumé at the flowering stage, and 0.2-0.3 degrees Baumé during the fruit growth period; (5) Zinc sulfate lime solution, i.e. the ratio of zinc sulfate, hydrated lime, and water is 1:4:240, mainly to control bacterial shot hole disease and plum red spot disease. (6) Bordeaux mixture 1:1:100, used at the late stage and at the leaf bud opening stage, mainly to control plum red spot disease.

2. Names and application concentrations of main insecticides: (1) Emamectin benzoate 800 times dilution (broad-spectrum insecticide); (2) 8% abamectin-pyridaben 600 times dilution (kills spiders, etc.); (3) Mineral oil emulsion 50-100 times dilution (kills scale insects, spiders, etc.); (4) Guosheng 1200-1500 times dilution (kills scale insects, spiders, etc.); (5) 80% dichlorvos 1000 times dilution (broad-spectrum insecticide, used at the flowering stage).