How should fruit thinning and bagging be done for Dangshan crisp pears?
How do you thin fruit and bag Dangshan crisp pears? Please guide. Fruit thinning and bagging for Dangshan crisp pears can refer to the following methods: 1. Fruit thinning technique: Thin crisp pear fruit starting one week after petal fall, completing it within one month; late thinning is not as good as early thinning. The amount of fruit retained should be based on the principle of not affecting flower bud formation the following year, ensuring the current year's yield and quality, not weakening the tree vigor, and maintaining a certain nutrient reserve. The fruit retention index should consider the following factors:
How do you thin fruit and bag Dangshan crisp pears? Please guide.
Fruit thinning and bagging for Dangshan crisp pears can refer to the following methods:
1. Fruit thinning technique: Thin crisp pear fruit starting one week after petal fall, completing it within one month; late thinning is not as good as early thinning. The amount of fruit retained should be based on the principle of not affecting flower bud formation the following year, ensuring the current year's yield and quality, not weakening the tree vigor, and maintaining a certain nutrient reserve. The fruit retention index should consider the following factors:
1. Based on tree vigor, tree age, planting density, and fertilizer and water conditions, set a yield target per unit area, calculate the average yield target per tree, then determine the yield by tree and calculate the number of fruit retained per tree based on an average single fruit weight of 250 g to 350 g, and then allocate the number of fruit retained according to the load capacity of each branch group.
2. Determine the number of fruit retained based on a leaf-to-fruit ratio of 25 to 30:1.
3. Determine the number of fruit retained based on a branch-to-fruit ratio of 4:1. For young trees with relatively strong vigor, the branch-to-fruit ratio can be reduced to 2.5 to 3:1; for weak trees and old trees, appropriately increase the branch-to-fruit ratio to 4.5:1.
According to a reasonable fruit retention index, in order to ensure high and stable yields of the tree, the following fruit thinning methods should be used:
1. Thin the middle fruit and keep the side fruit; thin small fruit and deformed fruit, and keep large fruit and well-shaped fruit.
2. Keep more and thin less on strong branches; thin more and keep less on weak branches.
3. Thin more and keep less inside the canopy, and thin less and keep more on the middle and outer parts; thin more and keep less on the top of the canopy, and thin less and keep more on the lower part of the canopy.
4. Thin more and keep less at the base and tips of main and lateral branches, and thin less and keep more in the middle, ultimately achieving uniform fruit distribution with appropriate spacing.
2. Bagging technique: 1. Selection of fruit bags for crisp pears: For bagging crisp pears, it is best to choose waxed bags or parchment bags with strong toughness and good air permeability. One week before bagging, soak them in a 50-fold dilution of 6% lindane powder solution up to 1/4 of the bag opening, and use them after drying, which can reduce the rate of yellow mealworms entering the bags.
2. Bagging period: For crisp pears, bagging is suitable from mid-May to early June.
3. Bagging operation technique: After selecting the pear fruit, open the paper bag and let the bag body expand, then use your hand to push up the middle of the bag bottom with slight force into a "W" shape, so that the two bottom corners are slightly lower and the ventilation and drainage openings are slightly open. Insert the fruit so that it hangs in the center of the bag. Hold the bag about 2 cm below the opening, fold the bag opening from the middle to both sides in sequence in a "folding fan" manner, and tie the binding wire (or iron sheet) tightly around the bag opening.
4. Pest control after bagging: After bagging, frequently investigate the damage by yellow mealworms inside the bags, sampling more than 3%. If yellow mealworms are found in 0.3% to 0.5% of the bags, spray 50% pirimicarb ultra-micro wettable powder at 3000-fold or 50% dichlorvos emulsifiable concentrate at 1000-fold, and spray the bags until wet. If the yellow mealworm infestation is severe, the bags need to be removed for control.
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