Key Technical Points for Apple Tree Training, Pruning, and Pest and Disease Control in Lingwu City

Apple Tree Training, Pruning, and Pest and Disease Control in Lingwu City

Lingwu City is located in the central part of the Ningxia Hui Autonomous Region. With superior natural conditions such as temperature, sunlight, and rainfall, it has extensive plantings of apples and other fruits and has long been known as the "Hometown of Flowers and Fruits." The Baijitan Nature Reserve is located within Lingwu City and was established in the 1980s. In recent years, Baijitan has made full use of the local superior natural conditions, continuously expanding the apple planting area and promoting advanced technologies such as training and pruning and pest and disease control, laying a solid foundation for improving the quality and efficiency of Baijitan apple trees. Based on the author's practice, the techniques for apple training, pruning, and pest and disease control are now discussed.

1 Training and Pruning Techniques

1.1 Pruning According to the Tree

The growth of apple trees is affected by two factors: internal causes and external causes. External causes include natural conditions such as terrain, climate, and soil, as well as cultivation measures such as soil, fertilizer, and water management and pest, disease, and weed control during cultivation. Internal causes include the selected apple tree variety, tree age, and growth vigor. Under the combined influence of internal and external causes, different apple trees require different pruning methods. Pruning should be done according to the tree, making adjustments based on the tree's growth vigor and fruiting situation, and formulating different pruning plans.

1.2 Using Short-Term Growth to Support Long-Term Development

Apple trees have a long lifespan and can bear fruit for many years, so pruning should be carried out in combination with the tree's growth conditions and load capacity. For apple trees, if heavy pruning is carried out blindly, it will prolong the time for the apple tree to enter the full fruiting period and reduce its economic lifespan. Therefore, while considering long-term planning, current benefits must also be considered. In pruning young apple trees, as many branches as possible should be retained to promote better growth, using short-term growth to support long-term development, so that training does not have a major impact on fruiting. Through appropriate training and pruning, a good tree structure can be cultivated, achieving early fruiting, high yield, and stable yield of apple trees.

1.3 Determining the Degree of Training and Pruning According to Tree Age

Apple trees of different ages have different growth conditions, and the degree of training and pruning also differs. For newly planted young apple trees, the degree of pruning should be light, retaining more branches to promote a more moderate tree vigor and faster fruiting; the scaffold branches of young trees should be heavily pruned to cultivate a permanent tree form; for old trees, because they have borne fruit for many years, their growth vigor is relatively weak, and many fine branches are distributed on the trunk, so heavy pruning should be the main approach to promote renewal and rejuvenation of old trees. At the same time as heavy pruning, care should be taken not to affect the fruiting of apple trees. When pruning fruiting branches, heavy pruning and light pruning should be combined according to actual conditions.

1.4 Pruning Should Distinguish the Primary from the Secondary

Affected by various factors, different parts of an apple tree grow unevenly, and there are phenomena such as uneven growth vigor between the upper and lower parts of the canopy. Branches that are too vigorous should be suppressed, and a combination of promotion and control should be adopted to ensure balanced tree vigor. The position and order of branches at all levels of an apple tree have a certain distinction between primary and secondary. During pruning, attention should be paid to distinguishing the primary from the secondary, and on the basis of retaining more branches, the order should be clear and branch distribution balanced. For the central leader, its absolute dominant position should be ensured during pruning; for the upper and lower main branches, the lower layer should be maintained as more vigorous than the upper layer during pruning; the growth vigor of main branches should be stronger than that of side branches, and when retaining auxiliary branches, they must not hinder the growth of scaffold branches. In short, branches at all levels should have a certain difference in growth vigor, achieving a clear distinction between primary and secondary.

1.5 Combining Winter Pruning with Summer Pruning

Winter pruning is mostly carried out before and after leaf fall, and should be done earlier rather than later to prevent "bleeding" after pruning. Generally, it is best to choose a tree canopy of the open-center type. Different apple tree varieties and planting conditions require different winter pruning methods. For some varieties that are prone to canopy closure in the orchard, the pruning amount during planting should be greater, adopting methods such as more thinning and less heading. For apple trees on barren soil with poor growth vigor, heavy pruning should be used in winter, adopting methods such as less thinning and more cutting. Summer pruning effectively makes up for the shortcomings left by winter pruning, enabling apple trees to bear fruit earlier and achieve high yields. Summer pruning methods are mostly branch thinning and shoot twisting, etc., to control overly vigorous branches and ensure a balance of growth vigor among branches.

2 Control of Major Pests and Diseases

2.1 Apple Alternaria Leaf Spot

Apple alternaria leaf spot is a disease that readily occurs in apple cultivation and can cause apple trees to show leaf drop symptoms early in the growing season, harming tree growth and being unfavorable for later flower bud formation and fruiting. Under certain conditions, apple alternaria leaf spot will gradually spread throughout the entire orchard, causing large-scale outbreaks. For control, diseased leaves should be promptly removed and uniformly subjected to harmless treatment. All diseased leaves should be pruned off before the pathogen spreads to prevent diffusion. This disease generally harms young buds. Therefore, young buds should be inspected regularly and control should be well carried out. Fungicides with good efficacy against apple alternaria leaf spot include mancozeb, etc., which should be sprayed in appropriate amounts according to actual conditions before the disease occurs or just as it begins.

2.2 Apple Phytophthora Rot

One of the diseases frequently occurring on apple trees in spring is apple phytophthora rot, which mainly harms fruits, root crowns, and other parts. When apple fruits develop apple phytophthora rot, their surface color darkens and the flesh rots, causing great losses; when the root crown develops this disease, the root crown rots. For the control of apple phytophthora rot, diseased fruits can be gathered and deeply buried, and methods such as laying grass on the ground can be adopted to prevent infection by apple phytophthora rot caused by muddy water splashing onto the fruits from the ground; the root crown area should be promptly turned over and dried in the sun, the diseased parts scraped clean, and lime sulfur mixture and other agents applied for disinfection.

2.3 Peach Fruit Borer

The peach fruit borer generally occurs mostly in July. In April to May, on the basis of intertillage of the soil, the tree plate can be cleaned up, and plastic film can be laid within 1 m around the trunk and the edges pressed down firmly, which has a good effect on preventing adult moths from emerging and climbing the tree to lay eggs; about 2 weeks after apple petal fall, sex pheromone traps can be hung in the orchard to trap and kill male moths of the peach fruit borer, interfering with the normal mating of the pest and thereby reducing the insect population; in July when the pest first occurs, pesticides such as fenpropathrin, Taoxiaoling emulsifiable concentrate, and chlorpyrifos can be sprayed.