What are the key points of summer management for citrus trees?

Among fruits, citrus belongs to the category with high yield, comprehensive nutrition, and easy storage. Citrus trees are also one of the common fruit trees in orchards. In summer, most fruiting citrus trees are in the summer shoot growth period, the rapid fruit enlargement period, the second root growth peak, and the fruit-setting period.So what are the key points of summer management for citrus?

1. Continue to do a good job in fruit preservation

The second physiological fruit drop of citrus trees is also called the June drop. In order to reduce fruit drop, it is necessary to strengthen foliar topdressing, evenly spraying the whole tree with “Quanshuguo” + “Haweiguo”. For those vigorous trees prone to fruit drop, summer shoots can be removed once every 10 days to promote fruit preservation.

2. Carry out tree body management

For adult fruiting citrus trees, summer shoot sprouting and growth need to be controlled through fertilizer and water management and bud removal. For heavily pruned trees, aged trees, top-grafted trees, and other citrus trees whose branches and trunks are exposed to strong light and prone to branch and trunk sunburn, the branches and trunks should be whitewashed to reduce light and heat effects. For young trees, when summer shoots grow more than 25-30 cm, pinching is needed to promote branching and shoot growth to expand the canopy.

3. Carry out fruit thinning

At the end of June, the second physiological fruit drop of citrus trees ends and rough fruit thinning begins. At this time, the fruit transverse diameter is mostly below 2.5 cm. This is mainly carried out for those citrus with many fruits, and rough fruit thinning should be carried out according to a leaf-to-fruit ratio of 15:1 —— removing diseased and insect-damaged fruits, deformed fruits, mechanically damaged fruits, small fruits, and overly dense fruits.

4. Apply fruit-swelling fertilizer and fruit-strengthening fertilizer

Rhizosphere topdressing: For plants with weak tree vigor and too many fruits, or unstable fruit set, or relatively small fruits, apply water-soluble fertilizer: humic acid or amino acid + high-potassium macroelement water-soluble fertilizer diluted 200 times and drenched 1-2 times as fertilizer for stabilizing fruits.

Foliar fertilizer spraying: During the rapid expansion period of young fruits in summer, mainly supplement medium and trace element fertilizers, such as calcium, magnesium, and boron, as well as biostimulants, such as amino acids or seaweed extracts, to improve plant stress resistance and reduce young fruit abscission caused by high temperatures and sunburn. Recommended scheme: amino acid calcium or sugar alcohol calcium + amino acids or seaweed.

For plants with average tree vigor, spring shoots that do not turn green and become yellow, slow young fruit expansion, and severe physiological fruit drop: spray potassium dihydrogen phosphate + brassin + amino acids or seaweed to supplement nutrients, promote fruit expansion, and achieve the purpose of stabilizing fruits.

5. Prevent and control pests and diseases

At this time, the plum rain season has arrived. With high temperature and high humidity, citrus rust mites enter a rapid proliferation period, and black spot disease first appears in early June. Lufenuron plus mancozeb 600-800 times solution can be used to control rust mites and black spot disease, etc.

For longhorn beetles, adults can be captured, and eggs and larvae removed. When larvae cannot be hooked out, use cotton dipped in 80% dichlorvos emulsifiable concentrate or 40% dimethoate emulsifiable concentrate and other undiluted liquids to plug the hole, then seal the outside with sticky mud to fumigate them to death. At the end of June and early July, control black spot disease once more. For scale insects, use Rui'ai chlorpyrifos during the first and second generation hatching periods.