How to manage fruit trees in summer? Technical key points explained in one article

Summer management of fruit trees is an important part of the year's fruit tree management work and has a huge impact on the yield of fruit trees in that year. So, what are the technical key points for summer management of fruit trees? The following technical key points are specially proposed.

I. Fruit management

1. Use hormones to preserve fruit. When 2/3 of the flowers have fallen, spray the tree canopy with 10 ppm “2.4-d” or 50 ppm “920” + 0.5% urea + 0.2-0.3% “monopotassium phosphate” mixed solution to preserve fruit, and spray again after 15 days. For navel oranges, use “Guodaduo” 3 times to preserve fruit, or use 12 ppm “E T-2” or “Lüsait” to prevent navel yellowing, and “Yihuangzhi” can also be used to coat the fruit top.

2. Fruit thinning and bagging. Shatian pomelo and summer orange are thinned and set in mid-to-late June, removing diseased fruit, deformed fruit, small fruit, and densely clustered fruit. The amount of fruit retained can be determined according to the leaf-to-fruit ratio. For sweet orange citrus varieties, 40—50 leaves are left for one fruit, and for Shatian pomelo, 100—150 leaves are left for one fruit. On the basis of fruit thinning and fruit setting, spray once with an insecticide and fungicide: use “Lüjing” 1000-fold solution + 50% “carbendazim” 600—800-fold solution or “Daconil m—45” 1000-fold solution. Bag promptly after the liquid dries.

II. Apply fruit-stabilizing fertilizer and fruit-swelling fertilizer well

1. Fruit-stabilizing fertilizer. In mid-May, fertilize according to the tree condition. For weak trees and trees with a large number of flowers, especially adult Shatian pomelo trees, soil fertilization should be applied once, mainly with phosphorus and potassium, to reduce physiological fruit drop.

2. Fruit-swelling fertilizer. In early-to-mid July (deciduous fruit trees in early-to-mid May, Shatian pomelo in late June), apply the first fruit-swelling fertilizer well. Generally, each fruiting tree is applied with 40—60 kg of human and livestock manure, 0.3 kg of urea, 0.5 kg of superphosphate, and 2—3 kg of plant ash (or 0.5 kg of potassium sulfate), while irrigating with 100—200 kg of water. After the Beginning of Autumn, apply the second fruit-swelling fertilizer to promote fruit expansion. The fruit industry station recommends the use of “Kaifeng” special compound fertilizer for fruit trees, which has a significant effect on improving fruit quality and yield.

3. Irrigation. After entering the summer drought period in July, whenever there are 7 consecutive sunny days, irrigation is needed once, with 100—200 kg per plant each time, to ensure the water needed for fruit expansion.

III. Seize the key period to prevent and control pests and diseases

1. Control of citrus red mites and yellow mites: While carrying out spring control, continue to do a good job in controlling red and yellow mites. On the basis of forecasting and prediction, carry out effective control. Effective pesticides include: “Nisuolang”, “Guosheng”, “Saomanjing”, “Jinbaman”, “Juemanba”, etc. The use of “Lüjing” biological pesticide has an especially good effect.

2. Scale insects: Scale insects occur commonly and rather seriously, so observation and control should be strengthened. For the pesticide, it is best to choose “Guosheng” 800—1000-fold solution and spray again after an interval of 7—10 days. “Lüjing” biological pesticide can also be chosen. At the same time, it can also control mites.

3. Longhorn beetles: From mid-May to early June, manually capture adult longhorn beetles, and from early June begin hooking and killing longhorn beetle eggs and larvae.

4. Rust mites: From June to September, begin control whenever leaves show a rust-copper color, once every 10 days, for 2—3 consecutive times. For the pesticide, 65% “zineb” 800-fold solution or “Guosheng” 1000-fold can be chosen.

5. Leafminer: Leafminer mainly damages tender shoots and mostly occurs from June to July. Control should be combined with bud wiping and shoot releasing. When buds grow to 2—3 mm, immediately spray for control, once every 7 days, for 2—3 consecutive sprays. Pyrethroid pesticides are mainly chosen, and “Lüjing” biological pesticide has an especially good effect.

6. Pear weevils, pear fruit borers, pear net bugs, pear black heart disease, etc.: 90% “trichlorfon” 800—1000-fold solution + 65% “Tuzet” (or “carbendazim”) 600-fold solution can be chosen for control.

IV. Do a good job in summer pruning of fruit trees

Summer pruning of fruit trees is divided into pruning before the flowering period and after the flowering period. Pruning before the flowering period aims to regulate the amount of pruning and preserve flowers and fruit, summer pruning from May to July aims to improve light and promote high-quality autumn shoots, and summer pruning from August to October aims to promote flower bud differentiation.

Pruning of young trees is mainly for shaping.

Main operations for summer pruning of citrus from May to July:

1. For summer shoots, fruiting trees should be thoroughly wiped out, and young trees should be pinched in time. Wiping summer shoots should be done early rather than late, mainly by wiping summer buds. For vigorous trees, leave 2—3 leaves on summer shoots and pinch the tips.

2. In July, cut off unreasonable large branches and branch tips in the tree canopy to improve ventilation and light penetration. At the same time, in combination with fruit thinning, partially cut back some flower-and-fruit-dropping branches and fruit-thinning branches to promote high-quality autumn shoots and lay the foundation for a high yield the following year.

3. Summer is the best period for branch pulling, top pruning (opening the skylight), and shaping of young Shatian pomelo trees, in order to improve canopy ventilation and light penetration; at the same time, it prepares for the use of hormones to promote flowering at the end of August.

V. Other work

1. Orchard weeding. To prevent soil erosion and maintain soil fertility, pulling weeds and no-tillage are advocated. Low-growing weeds are retained to improve the orchard ecological environment and lower soil temperature in summer. Tall weeds can be pulled out or cut at the middle to improve orchard ventilation and light penetration conditions.

2. Do a good job in “top grafting and variety replacement” for old and inferior fruit trees, as well as sprout removal, branch support, and tip pinching for top-grafted and variety-replaced trees.