Summer management measures of pruning and fertilization to control diseases and insect pests of citrus

Summer is a critical period for citrus growth and development. In order to ensure high quality and high yield of citrus, it is very important to strengthen summer management. The specific measures are as follows:

Citrus pruning

1. Fertilization in summer

Fertilization for young trees: quick-acting fertilizer is applied every 20 days or so, which can be applied in a ditch 30-50 cm away from the trunk, and the amount of fertilizer is determined according to the size of the tree. At the same time, do a good job of foliar fertilization and replenish the trace elements needed by the tree in time.

Fruit tree fertilization: the middle and last ten days of June is the citrus expansion period, and the amount of fertilizer application accounts for about 60% of the annual fertilizer application. The method is to open a ditch outside the crown dripping line, with a ditch depth of 15-20 cm and a width of 25-35 cm. Generally, the amount of organic fertilizer (rotten cake fertilizer) 1.5 kg 2.5 kg or compound fertilizer 1 Mel 2 kg is applied according to 100 jin of fruit.

Second, summer pruning

The purpose of summer pruning is to adjust the tree structure and improve fruit quality. The best time for pruning is from June 20 to July 15. The trees with large fruiting mainly cut flowers and fruit branches and decaying branches. The trees with less fruit should be pruned combined with the transformation of tree shape, remove the upright and dense branches in the middle and upper part of the crown, retract or truncate the branches around the crown, so that the crown height is controlled at about 2 meters. The tree with partial results can be pruned by alternating results and updating alternately. After pruning, proper root cutting should be carried out combined with fertilization, branch protection should be carried out, and fertilizer and water management should be strengthened. Due to the high temperature in summer and more Rain Water, citrus is easy to produce a large number of summer shoots, consume a lot of nutrients, aggravate the second physiological fruit drop, and allow the summer shoots to grow, which may result in reduced production or even no harvest. Therefore, draining summer shoots is the most effective measure to protect fruit. Generally speaking, young and middle-aged trees entering the fruiting stage should pay more attention to timely wiping because of less fruit hanging, strong tree strength and more summer shoots. When summer shoots grow 7~10cm, they should be completely erased from the base. Apply it again at intervals of 5-7 days, thoroughly in early August, and then put on autumn shoots. Trees that enter the full fruit period, or trees with more fruit, have a small number of summer shoots, so they should wipe buds in time and put autumn shoots again in late July, so as to lay the foundation for stable production next year.

III. Pest control

1. Control of large food flies: before spawning on the adult fruit in early June, 1000 times liquid of trichlorfon or 48% chlorpyrifos (Lesben) 1000 times liquid plus 3% brown sugar (which can simultaneously prevent sagittal scale and citrus whitefly) can be used to spray 3 canopies every time, once in 7-10 days, three times in a row. In addition, sweet and sour liquid is hung on the crown to trap and kill adults.

2. The control of Arrowhead scale, embroidered tick and citrus whitefly: in the middle of July, we should choose 2000 times EC or 73% EC 2500 times.

3. Control of leaf miner: when citrus is slightly longer than 0.5-1cm in early autumn, 1000 times of chlorpyrifos, 1000 times of chlorpyrifos or 1000 times of insecticidal are used to control leaf miner, once every seven days for 3 times in a row.

4. For the prevention and control of longicorn beetles, the first is to kill adults in time; the second is to brush the trunk with lime to resist longicorn beetle spawning; and the third is to check the trunk in time. Once moisture or sawdust is found, first kill the larvae with wire hook, and then fill the hole with poisoned cotton.

Fourth, strengthen water management, fight drought and drainage.

The water management of orange orchard in paddy field is mainly to grasp the ditching and drainage work in plum rain season and summer and autumn, and to control water properly so as to restrain the germination of late autumn shoots and improve fruit quality. Drought and water conservation should be done in dryland orchards to prevent high temperature and drought from falling fruit. When it is found that the citrus leaves begin to curl, it is necessary to draw water into the orchard in time, adjust and humidify with water, and loosen the soil by ploughing to improve the ability of water and fertilizer conservation. In order to improve the orchard microclimate, reduce fruit drop, and promote strong fruit.