Proper management during the expansion period of late-ripening apples in August helps to increase yield

August is the secondary flower bud differentiation period of apple trees and the expansion period of middle and late ripening apple varieties, during which the photosynthesis is strong, the photosynthetic accumulation is accelerated, and the growth of new shoots is accelerated, but most of the new shoots transition from slow growth to cessation of growth, and a large number of absorbing roots occur. The absorption of water and nutrients is also accelerated. The key points of apple tree management in August are as follows:

Apple tree pruning

1. Pruning

At the beginning of August, the strong branches of young apple trees were cut short to promote the secondary secondary shoots, which could form flower buds in the same year, achieve the purpose of more flowers, early and high yield, cultivate branch groups and control the crown. It is appropriate to leave 3-5 leaves at the base of spring shoot. In the first ten days of August, for the big trees with too many auxiliary branches, part of the big branches can be removed, and the overgrown branches, erect branches and overgrown branches should also be cut according to the space, so as to improve the ventilation and light transmission conditions of apple trees and improve the quality of flower buds. At the beginning of August, the annual growing branch was taken to open the angle, and the xylem of the new shoot was injured, so that the branch tissue was damaged and drooped or horizontally, so as to restrain the top growth dominance, promote the secondary secondary shoot germination and increase the number of branches and leaves of young trees. The opening angle of the branch begins in late August, when the branch is relatively soft, and it is not easy to appear on the back of the branch after the angle is opened, which is a good time for the backbone branch and large auxiliary branch to open the angle. young trees should stick to pulling branches every year before they are formed. do not draw into a bow.

II. Soil, fertilizer and water management

Combined with spraying 0.3% urea + 0.5% potassium dihydrogen phosphate to promote shoot ripening and improve cold resistance. Spraying again after 10 days can improve the coloring and sugar content of the apple. In apple orchards with bitter pox disease, 0.5-1% calcium chloride was sprayed continuously for 2-3 times at the beginning of August, mainly spraying apples, which can increase pulp hardness and improve storage resistance. Autumn shoot growth gradually stopped in the middle of August. Topdressing compound fertilizer could prevent premature senescence of leaves, promote nutrition accumulation of apple trees, restore tree potential, be beneficial to flower bud differentiation and apple expansion, and increase fruit setting rate and shoot growth in the next year. Watering combined with topdressing plays a good role in increasing yield, coloring and quality. After watering or rain, timely ploughing and weeding, young orchards can be ploughed deeply, with a depth of about 20-30 cm, in order to thoroughly remove weeds and promote root growth.

Pick the bag of apple

III. Apple Management

Bagged apples of medium-ripe varieties began to be bagged in mid-late August. The double-layer bag should first go to the outer bag, and then to the inner bag after 3-5 days; the single-layer bag will tear the paper bag longitudinally, leave the residual bag on the apple, and remove it 3-5 days later. Pay attention to choosing to remove the bag in the middle of the day when the temperature difference inside and outside the bag. After removing the bag, the leaves were picked, the fruit was turned, and the reflective film was applied to promote the overall coloring of the fruit. The marshal varieties which are easy to drop fruit before harvest are sprayed with 30-40 mg / kg naphthalene acetic acid in mid-August and at the end of August, that is, one month and half a month before harvest, to prevent fruit drop before harvest.

IV. Pest control

Continue to investigate and treat rot, alternately use 1 ∶ 2-3 ∶ 200 times Bordeaux solution, 50% prohydantoin wettable powder 1000-1500 times solution, 50% mancozeb wettable powder solution to control anthracnose, ring disease, spot leaf disease and other diseases, find infected apples, remove the deep burial in time. 2000-fold solution of 25% thiazuron 3 was used to control Lepidoptera pests such as Spodoptera litura and Spodoptera litura. In late August, apple tree trunks were tied with grass to trap red spiders and other pests to survive the winter, and then thawed and burned before thawing the following year, so as to reduce the population density. When the apple is unbagged and examined for the presence of Kang's pink scale larvae, the tree should be sprayed with 52.25% Nongdile 1500-2000 times liquid to control its harm.