Technical points of Flower and Fruit Protection of growing Citrus

The period from budding to stable fruit of citrus trees is the most important period of the year. In order to have a good harvest, comprehensive flower and fruit protection measures must be taken according to the growth status of citrus trees and the changes of weather.

1. Rational fertilization: for citrus gardens that were not fattened last winter, organic manure should be applied as soon as possible. Each adult tree should be buried in the rhizosphere with 5: 10 kg of chicken manure or 1: 2 load of soil fertilizer, plus appropriate amount of urea. The principles of fertilization in flower and fruit preservation period are as follows: nitrogen in the early stage, heavy potassium and phosphorus in the later stage, and the combination of soil fertilization and extra-root topdressing. Xiehua fertilizer applied compound fertilizer plus appropriate amount of urea in citrus flowering stage to supplement the nutrients consumed in flowering stage in time; stable fruit fertilizer applied potassium fertilizer plus appropriate amount of phosphorus fertilizer; strong fruit fertilizer should apply compound fertilizer plus potassium fertilizer. Extra-root topdressing should be sprayed with 0.2% potassium dihydrogen phosphate twice after spring bud germination and before flowering, nucleotide was sprayed in overcast and rainy days, 0.1% borax was added once, and foliar fertilizer was applied 3 times in combination with pest control or fruit protection in young fruit stage. 0.1% magnesium sulfate and 0.1% zinc sulfate were added to the foliar fertilizer for the first time.

Second, soil management: repair the drainage ditches inside and outside the orchard to remove stagnant water, so as to prevent stagnant water from affecting root growth or even causing flowers and fruits to fall. In the dry and hot weather for more than 10 days, it is necessary to irrigate the soil in time to keep the soil moist and loose, which is beneficial to the root group absorbing water and fertilizer.

Third, scientific use of growth regulators: the plant growth regulators commonly used in citrus fruit protection are 2mae4murD, antiseptic, triacontanol, 920, fruit protector and so on. After flowering, they are used 2-3 times and sprayed once every 15 days. The effect of cross-use of growth regulators is ideal, and the effect of 920 or triacontanol is better for seedless and seedless citrus varieties.

Fourth, pest control: there are mainly red, rust spiders, aphids, flower bud maggots, malignant leaf insects, anthrax, scab and so on. Dimethoate or monocrotophos can be used to control aphids in spring; red spiders should be controlled in the early and middle of April (if drought occurs in early March); acaricides or biological pesticides can be used to control rust spiders; organophosphorus pesticides are sprayed at the early bud stage to kill flower bud maggots and malignant leaf insects; the disease is mainly controlled, and fungicides such as copper oxychloride or topiramate can be used.

Fifth, control early summer shoots: wipe early summer shoots in time from May to mid-June to avoid competition for fertilizer, which is beneficial to the development of young fruits and reduce fruit drop. For the vigorous trees with few flowers and fruits, the fruit can be cut and protected 25 days after flowering, and the summer shoot can be controlled at the same time.