Talk about the root diseases of citrus, although these diseases are not common, but once they occur, it is more troublesome. Therefore, many of them are focused on prevention, and experienced technicians will carry out root prevention treatment once a year to improve the soil environment by increasing organic bacterial fertilizer and preventing problems before they occur.
The root and root neck diseases of citrus are mainly foot rot and gum disease, and the following figure is the treatment of citrus gum disease.
Today mainly to explore the problem of foot rot, we all know that trees are afraid of peeling, because the bark is the channel for transporting nutrients, if our citrus trees have foot rot, then the bark is going to rot, which has a great impact on citrus trees, and even the phenomenon of death.
This is a citrus tree with a rotten foot in Wuming, and the leaves have fallen in large numbers, dried up, and declared that they have been dug up.
The feet of the young sweet orange tree rot, causing the plant to die.
Citrus foot rot is also known as skirt rot, rotten scars, and some people call it root rot. It is an earth-borne disease that harms the base of the main trunk of citrus and occurs in all citrus producing areas in China.
At the beginning of the foot rot disease, the bark of the diseased part is irregular wet rot, the color brown often flows out of the brown glue, with the smell of lees, the disease extends to the xylem, so that the xylem discoloration rot, the junction of disease and health is obvious, the bark is cracked and peeled off in the later stage of the disease, and the xylem is exposed.
Sugar orange citrus foot rot root condition, the root system is almost cracked, rotten, nutrient absorption can not be absorbed.
We dig it out and take it to see, the rot is serious, there is no way to treat, therefore, in advance prevention, pay attention to observation, do not wait until the onset of the disease and then look around to ask how to treat.
Discussion of pathogenic bacteria of citrus foot rot:
Some people say it's Phytophthyclus, some say it's Fusarium, so what is the real situation?
Most reports suggest that foot rot is caused by Phytophthycosis parasitic bacteria, Phytophthora citrus, and Phytophthora pepper, while a small number of reports suggest that it is caused by Fusarium or a combination of both.
In fact, Phytophthora is the main pathogen, and kumquat develops soon after inoculation with Phytophthora, while Oxytetracycete inoculation has no obvious symptoms and is therefore a secondary pathogen.
Then, in the pathogens of Phytophthora, they are mainly divided into two types, one is Phytophthora citrus and the other is Phytophthora tobacco. In the subtropical areas such as Liangguang, tobacco Phytophthycoma is the mainstay, while Sichuan and Zhejiang are dominated by citrus Phytophthora.
Yan Huahua et al., inoculated with Phytophthora tobacco ymj-03 to different varieties of citrus to observe the onset of one disease afterwards.
Tobacco Phytophthycosis is very popular in Guangdong, and the area of citrus in Guangxi has expanded rapidly in recent years, especially attention should be paid to prevention and control in advance. Citrus aurantium is strongly resistant to foot rot, but it cannot resist the outbreak of the disease.
The harm of citrus foot rot mostly occurs from late March to early May, and the onset of disease is severe from June to August in high temperature and humidity, and the rapidest expansion. In general, sweet oranges are the most seriously affected, followed by red oranges and Wenzhou mandarin oranges.
Phytophthora is a low-grade fungus, when a wound appears on the neck of the citrus root, the pathogen will take advantage of the gap to enter, in the high temperature and rain, poor drainage, low-lying orange orchard, or planted too deep, the graft interface buried in the ground, the tianniu hazard and management conditions extensive orange orchard disease serious disease.
Citrus roots are harmed by celestial cattle.
In addition to infestation from insect wounds, frostbite, mechanical injuries and other wounds, it can also be invaded by natural pores such as skin pores and stomata, with a long incubation period under low temperature conditions, and under medium temperature and high humidity conditions, 4-5 days can show symptoms, and when the high temperature and drought are sufficient and the sun is sufficient, the harm of the pathogen will be inhibited.
Excessive circumcision, lack of attention to disinfection, protection against foot rot caused by the disease.
Prevention and control methods of citrus foot rot:
First, use disease-resistant rootstocks. Try to use disease-resistant rootstocks such as citrus shells, in orange orchards with high groundwater tables or dense planting, you should avoid using rootstocks such as sweet oranges and red oranges, and appropriately raise the grafting site when raising seedlings, plant appropriately shallow, and expose the grafting interface to the ground to reduce the chance of disease. The selection of anti-foot rot resources as rootstock is the most economical and effective measure to prevent and control foot rot, and citrus, orange, lemon, wolfberry orange and so on are commonly used as rootstocks in production.
The second is to strengthen cultivation management. Increase decomposing organic fertilizer, reduce the amount of chemical fertilizer, improve the soil of the garden, do a good job in tree tray care, and drain plants with low-lying orange orchards or high groundwater levels to prevent long-term accumulation of water. In winter, apply whitening to the neck of the citrus root to protect it from frost damage, and care is taken to prevent wounds caused by the borer holes of the tengu. When managing orange groves, try not to cause wounds and damage to the main stem and graft.
The method of leaning is adopted, and 2-3 citrus rootstocks are attached.
The third is to rely on the connection of disease-resistant seedlings. Serious diseased plants should eliminate the decay site of the disease, and connect 2-3 disease-resistant seedlings at the upper health base of the trunk, such as citrus shells, limes, etc., to enhance the disease resistance of foot rot. The original rootstock is removed in time after the connection is generated, and the original root system is replaced by the new seedling. The effect of this method on young orange trees within 10 years of age is quite obvious.
Master Ling Fawen's citrus grows after receiving it.
Many people can not do the previous work after the position, will be easy to infected with foot rot, the most important is the citrus root system, root neck position protection, foot rot bacteria is soil-borne disease, soil problems, tree potential is not good, natural easy to get sick, at present, the state also advocates fertilizer reduction, increase the application of organic fertilizer, the best is high-quality biological fertilizer, through the soil protection of beneficial bacteria, to achieve early prevention, reduce the effect of disease.
If you really can't do it, just take the medicine:
From top to bottom, the efficacy is getting worse and worse, the best bacteriostatic effect is enoyl morpholine, the second is azole daisen lian; the worst is methylthiopramine, but the ingredients, formulas, dosage forms of each manufacturer may be different, so it is not listed, according to the local retail store recommendation, choose a large manufacturer.
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1 dispensing: take potassium permanganate and water to prepare potassium permanganate solution;
2 Pretreatment: the soil of the root-neck disease site is peeled open, the lesion site is exposed, and the diseased tissue and the normal tissue around the lesion tissue are scraped with a disinfected tool;
3 pre-spraying: spraying the pretreated part with the potassium permanganate solution;
4 ultraviolet radiation: cover the UV lamp and the pre-sprayed part with a black cloth, and then turn on the UV lamp to illuminate the pre-sprayed part for 30min;
5 Application: the potassium permanganate solution is evenly applied to the site that has been irradiated by ultraviolet radiation;
6 Bandaging: bandaging the part that has been coated with disinfectant cotton;
7 Cover: Cover the exposed area in step 2 with sterilized soil. The above method is for reference only.
References: Multi-method simultaneous prevention and control of citrus foot rot, Cao Dihuan; Identification of citrus foot rot bacteria and determination of resistance to citrus germplasm, Yan Chemical; Identification of kumquat foot rot pathogen, Zhu Li; Indoor screening of citrus foot rot fungus phytophthora parasitica fungicide, Huang Jinglong; Citrus disease and insect pest primary color atlas, Cai Mingduan, etc.