Management experience of High temperature and humidity season in Apple Orchard

High temperature and humidity season is the key period for prevention and control of diseases and insect pests. At the same time, apple shoots also began to enter the second flourishing period, fruit development entered the expansion period, do a good job in tree growth regulation, promote good development of young fruit is the key management in this period.

I. Strengthen fertilizer and water management

1, reasonable topdressing on apple trees topdressing or not to be determined according to the variety, fruit yield and early fertilization, can be applied once phosphorus, potassium fertilizer, mainly potassium fertilizer, fertilizer amount depends on the tree. American No. 8, Gala and other mid-early varieties, topdressing in early July, Red Fuji apple in mid-July to mid-August try to catch up with fertilizer. Because July and August are in rainy season, if the weather is not dry, do not water, and fertilize in combination with rainfall.

2, foliar fertilizer in July and August combined with foliar spraying phosphorus, potassium, calcium, iron fertilizer, etc., to increase the sugar content of the fruit, promote coloring, reduce the physiological diseases of the fruit has an important role. Commonly used fertilizers are calcium superphosphate, potassium dihydrogen phosphate, potassium sulfate, plant ash and ferrous sulfate. Potassium dihydrogen phosphate and calcium chloride are used together in production, and the concentration of total salt concentration (total percentage content of soluble fertilizer) should not exceed 0.5%.

3, orchard drainage, weeding in the rainy season orchard can not be accumulated for a long time, otherwise it will affect the orchard soil permeability and apple tree root growth. Drain water in time after rainfall to keep the soil humidity of orchard relatively stable. After watering or rainfall, hoe in time to remove weeds in the garden.

II. Regulation of tree vigor

July, August suitable for apple tree nutritional growth, especially the early fruit stage young trees, fruit less mature trees easy to vigorous growth in summer and autumn, if not regulated, will affect flower bud differentiation, resulting in nutrient loss, tree shape disorder, reduce fruit quality, therefore, according to the age, tree vigor, fruit and other conditions, take appropriate measures to regulate, maintain tree vigor robust growth. Generally, paclobutrazol with 150-00 times solution was sprayed once in the first and middle of July. For young trees with no or few fruits, the second trunk or main branch girdling can be carried out at the beginning of July. At the same time, we should do a good job in summer pruning, focusing on thinning upright branches on the back, excessive branches in the bore, competing branches and useless branches affecting the light, twisting the branches slowly, so as to control the vigorous growth, improve the light conditions, promote the fruit development and flower bud formation.

III. Prevention of apple sunburn

The damaged apples showed that the sun surface was dehydrated and scorched, producing reddish brown nearly circular spots, which gradually expanded to form dark brown spots with pale yellow halo around them, which seriously affected the commodity value of apples. July and August are critical months for preventing sunburn.

1, timely irrigation days drought, should immediately irrigate, reduce the occurrence of sunburn.

2, the tree plate covered in the high temperature and drought before the arrival of a layer of 20 cm thick straw, grass or wheat chaff on the tree plate, both to preserve moisture, but also to reduce the ground temperature, can prevent the occurrence of sunburn.

3. Covering the fruit surface with tung tree leaves, castor leaves or broad-leaved grass with large leaf area on the sunny surface of the fruit prone to sunburn can reduce the direct sunlight and reduce the occurrence of sunburn.

4, paste white paper in the sun prone to sunburn fruit surface with emollient oil paste a piece of white paper, can reflect sunlight, prevent sunburn.

5. Spray lime milk Apply a layer of lime milk on the sunny side of the apple, which can reflect light, prevent sunburn and sterilize.

6. Spraying Meifeng 400 times solution of Qisu amino acid fertilizer 2-3 times in late July and August, with an interval of 15 days each time, can not only increase drought resistance, reduce sunburn, but also promote fruit development, improve fruit quality and make flower buds full in the next year.

7, combined with spraying water in the evening when the sun sets or oblique, can spray water to the crown to reduce sunburn.

IV. Pest control

1, pest control in this period to red spider, leaf miner moth, leaf roller moth, apple cotton aphid and ring disease, anthracnose, early defoliation disease and other pests for the control focus. Control of red and white spiders should be based on the local temperature, rainfall and occurrence of timely medication, commonly used pesticides are 1.8% abamectin EC 4000 times, 5% kasike EC 1000 times, 20% Misijing suspension 2000 times, 5% Nisolon EC or 25% Beiluoba WP and 2000 times of Comite EC and so on. Leaf-miner moth and leaf roller moth should be prevented in May and June, and re-applied in early July. The commonly used pesticides are: 25% chlorfenuron No.3 colloidal suspension 1500 times, 1.8% abamectin EC 5000 times, 2.5% kung fu or fenvalerate 3000 times; apple cotton aphid 48% Lesben EC 1000 times.

2. Disease control July and August are another critical period for preventing ring disease, anthracnose and early leaf blight. In terms of medication, internal inhalants and protective agents should be used alternately. Generally, protective fungicides should be used before rain, and internal inhalants should be sprayed in time after rain. In production, full bagging cultivation should be carried out, focusing on the prevention and control of early deciduous disease. Generally, the pesticide should be sprayed once in the middle of July, the first ten days of August and the last ten days of August. The effective pesticides are: 1∶2∶200-240 Bordeaux mixture, 800-1000 times solution of 50% carbendazim WP, 1000 times solution of 70% thiophanate-methyl WP, 600-800 times solution of 70% or 80% mancozeb WP, 1000 times solution of 50% prohydantoin, 1000 times solution of 10% doxorubicin, etc. Bordeaux mixture and one of the above fungicides alternate use effect is good, generally every 20-25 days spray a Bordeaux mixture. Red Fuji apple orchard in June-August spray 3 times, into September to stop, so as not to affect the coloring.