A Detailed Explanation of Key Apple Tree Management Techniques in Midsummer

August is the peak period of flower bud differentiation and rapid fruit enlargement in apple trees, and also the peak period for the occurrence and development of pests and diseases; tree management during this period is very important, and the key management points are summer pruning, pest and disease control, topdressing, weeding and drainage.

Summer pruning: First, for strong vigorous branches and water sprouts, bend the branches to open the branch angle and moderate the growth vigor; second, thin out some vigorous branches that shade the tree; third, cut back the middle part of spring shoots, the blind node of spring-autumn shoots or the middle part of autumn shoots to promote autumn secondary shoots and form flower buds, making them good fruiting branch groups; fourth, for fruit trees with excessive fruit load and fruiting sites moving outward, hang and prop the branches to prevent branch breakage and avoid fruit overlapping, which is beneficial to fruit growth, development and coloring; fifth, pinch the tips of vigorous shoots to promote the formation of short branches and flower buds.

Pest and disease control: If a summer drought occurs, red spider mites are prone to large outbreaks and severe damage, and a mixture of 1.8% abamectin aqueous emulsion at 3000-4000 times plus Roushuitong at 4000 times can be sprayed once for control; in orchards with severe apple woolly aphid infestation, remove the infested shoot tips and spray a mixture of 48% chlorpyrifos (Mozhan, Anminle, Haolaoli) emulsifiable concentrate at 1000-1500 times plus 25% imidacloprid suspension concentrate at 2000-3000 times plus Roushuitong at 4000 times for control; at the initial occurrence stage of leaf rollers and leafminers, choose to spray 25% diflubenzuron suspension concentrate at 1000-1500 times, or 40% triflumuron suspension concentrate at 6000-8000 times; for the peach fruit borer, when the egg-fruit rate reaches 0.5%-0.8%, spray on the tree, with commonly used agents including 20% fenpropathrin emulsifiable concentrate at 2000 times and 5% cyhalothrin emulsifiable concentrate at 2500 times (also controlling pest mites), etc., focusing the spray on the fruit surface; continue to do a good job of manual capture and killing of leaf rollers, boat-shaped tussock moths, cicadas, mulberry longhorn beetles and citrus longhorn beetles; in rainy seasons, according to the situation, spray 70% thiophanate-methyl (Lizhi, thiophanate-methyl) wettable powder at 800-1000 times, or 25% propiconazole (Jinlishi, Diliutuo) emulsifiable concentrate at 2000-3000 times, or double-strength Bordeaux mixture 1-2 times. Control brown spot disease, alternaria leaf spot, ring rot, anthracnose and round spot root rot; blacklight insect lamps, yellow sticky traps and sex pheromone lures for lepidopteran pests can also be set up to trap and kill pests.

Topdressing: Applying fruit enlargement fertilizer helps promote new root growth, improve leaf function, increase single fruit weight, raise the rate of high-grade fruit and yield, plump flower buds and tree nutrient accumulation, improve tree resistance, and lay a good foundation for high yield and quality in the current year and a good harvest in the following year. Generally, about 50 kg of quick-acting compound fertilizer (high-nitrogen and high-potassium compound fertilizer) is applied per mu, which helps promote fruit enlargement; applying phosphorus and potassium fertilizer can increase fruit firmness and sugar content and promote fruit coloring.

Weeding: In August, weeds grow vigorously, competing with fruit trees for fertilizer and water, affecting ventilation and light penetration in the orchard, and breeding pests and diseases, so timely intertillage and weeding should be carried out. The lush green grass in and around the orchard, beside ditches, around the orchard edge and along roadsides can be cut and pressed under the tree canopy. Orchards planning to implement artificial grass growing can sow during the rainy season. Orchards that have already implemented artificial or natural grass growing should cut the grass in time when it grows to 20-30 cm high. It is advocated to use crop straw or weeds and other grass-source materials to cover the orchard, which not only reduces the breeding of pests and diseases, but also lowers temperature, preserves moisture and improves the soil.

Drainage: August is the rainy season, with frequent and heavy precipitation, so flood control, drainage, soil and water conservation, and wind protection must be done well. In the rainy season, the soil has much water and poor aeration, which inhibits root growth and absorption. Flatland orchards can adopt ridge cultivation management techniques, that is, take 10 cm of topsoil from between the rows and place it in the rows, so that there is a height difference of about 20 cm between the ground between the rows and within the rows, increasing the topsoil layer under the canopy, which can both store and retain water and drain water to prevent waterlogging, promote nutrient absorption, and avoid root diseases caused by water accumulation. For waterlogged plants, scrape away the soil at the root crown and expose it to dry, so that the root system can recover as soon as possible.