Key Technical Points for Spring Production Management of Citrus

At present, it is the stage when citrus spring shoots are sprouting, which is also a period of the year when pests and diseases occur more frequently. The vigor of tree growth, the degree of pest and disease control, the level of yield, and the quality of fruit are all very directly related to the management during this period. Therefore, in production, on the basis of winter management, attention should be paid to spring production management as a key link.

I. Soil Management

1. Dig drainage ditches. Dig good furrow ditches and border ditches within the orchard area, with a ditch depth of 40 cm and a width of 30 cm, to facilitate drainage during the rainy season and daily irrigation.

2. Plant green manure. Around the tree disks within the orchard area, plant low-stalk crops such as clover, ryegrass, Chinese milk vetch, and legumes and vegetables, to conserve moisture, prevent soil moisture evaporation, and increase soil organic matter and looseness.

II. Fertilizer and Water Management

During the spring shoot emergence period of citrus, nitrogen and phosphorus fertilizers are mainly used, combined with foliar topdressing of 2‰ urea + 3‰ monopotassium phosphate; for citrus orchards that did not apply base fertilizer in winter, apply a basal fertilizer once at the drip line of the tree disk, applying 50 jin of human and livestock manure, 0.2 jin of urea, 0.3 jin of phosphate fertilizer or ternary compound fertilizer per plant, mainly by strip ditches or hole application, with the ditch depth preferably exposing roots, and the fertilization ditches (holes) should be dug opposite each other, so as to alternate in orientation at the second fertilization. Fertilizer must be mixed evenly with the soil to avoid fertilizer damage. The amount of fertilizer applied should be determined according to tree vigor, fertilizing according to the tree: weak trees should be given more, and vigorous trees should be given less or not at all.

At the same time, when flower buds show white and when two-thirds of the flowers are open, spray boron externally to the roots; 3‰ borax fertilizer can be used for foliar spraying, to ensure flower quality and increase the fruit-setting rate.

III. Pest and Disease Control

On the basis of winter control, after the beginning of spring, attention should be paid to the control of diseases such as brown spot and anthracnose. The main agents are: 800-1000 times liquid zineb, 800 times liquid thiophanate-methyl, 1500 times liquid chlorothalonil, 600 times liquid copper hydroxide, etc. In pest control, attention should be paid to the control of pests such as citrus blossom midge, flower thrips, scale insects, red and yellow spiders, and aphids. The main pesticides are: 1000-1500 times liquid chlorpyrifos, 3000-5000 times liquid imidacloprid, 1500-2000 times liquid pyridaben, 800-1500 times liquid dichlorvos, 2000 times liquid rotenone.

Note: When spraying, spray evenly on the underside and upper side of leaves. Pesticides should be used alternately to avoid developing resistance. Highly toxic pesticides are prohibited to avoid pesticide residues.