What are the common varieties of citrus? What are the symptoms of citrus Huanglong disease?

Citrus Huanglong disease can be harmful almost all the year round, and it can show symptoms in every new period, but the symptoms in autumn and winter are the most prominent and easy to be identified, which do great harm to the branches, leaves, fruits and roots of fruit trees. So what are the common varieties of citrus? What are the symptoms of citrus Huanglong disease? Next, let's have a look with the editor.

What are the common varieties of citrus?

1. Sugar orange: listed in late December, one of the citrus varieties with stable and high yield, with sweet and sour taste, is very popular.

2. Kumquat: kumquat can be put on the market one after another in November until May of the following year. Kumquat is a late-maturing variety, so we need to pay attention to anti-freezing in planting.

3. Nanfeng tangerine: it matures in the first and middle of November every year, and it has been cultivated for more than 1300 years. It has been planted for three years and has a high yield for six or seven years.

4. Ponkan: also known as mandarin, it matured from mid-November to December. The old variety is now out of fashion.

5. Gongkan: also known as emperor mandarin, the official maturity period is from late November to mid-December. By the China Fruit Circulation Association awarded "China famous Fruit", "China Citrus King" and other honorary titles, has important economic value.

6. Gannan navel orange: it is mature from late November to early December, with crisp and tender meat, melted residue, strong sweet and fragrant flavor, thick skin and not easy to peel.

7. See you in spring: also known as rake mandarin, it is on the market in mid-late December and can be hung up to April at the latest. Late-maturing hybrid mandarin varieties are the most promising hybrid mandarin varieties in Japan.

8, do not know the fire: also known as ugly orange, listed in February to March the following year, the taste is extremely sweet, overwintering extreme weather risk, high maintenance cost, big and small years.

9. Fertile mandarin: listed from February to March, early bearing and high yield, wide adaptability, beautiful fruit appearance, good quality, late ripening period, long harvest time, spiny, easily infected with citrus canker and fruit drop during ripening period.

10. Maogu mandarin: it is on the market from February to mid-March, with early high yield, strong affinity, strong cold resistance, late ripening, especially serious sunburn fruit, white sunscreen and high requirements for climate.

What are the symptoms of citrus Huanglong disease?

1. Symptoms of leaf disease

The main symptom of Huanglong disease on the leaves is the chlorosis of the leaves. The yellowing phenomenon caused by this disease is generally dispersed and distributed on the leaves like a yellow smoke halo without a clear yellowing edge. In addition, the yellowing phenomenon on the leaves generally extends from the veins, margins and bases of the leaves to the mesophyll tissue in the middle, but there are great differences in the yellowing degree and area of different leaves, some leaves are yellow and green, and some leaves are yellow. even if it is the same leaf, the yellowing color on the leaf is dark and light. For the leaflets on diseased trees, most of the new heart leaves will appear mosaic symptoms of smaller, pointed, yellow and green leaves.

2. Symptoms of slight branch disease

The symptoms of branches on citrus trees with Huanglong disease were more prominent in each period, especially in summer, autumn and winter, which were mainly manifested as new yellowing, branches not turning green at maturity, and oil green turning bright yellow in the crown of diseased trees. in addition, the yellowing phenomenon of the branches of the injured trees is relatively uniform, and the leaves on the diseased trees are easy to wither too early.

3. Symptoms of fruit disease

The most intuitive manifestation of Huanglong disease in citrus fruit is abnormal fruit color, smaller fruit size, fruit hardening and deformity, and poor taste. The common symptoms of damaged citrus fruits are as follows: the pedicel of ① diseased fruit turns yellow and orange-red, but the top or other parts of the fruit are not colored according to turquoise; the size and single weight of ② diseased fruit are significantly smaller than those of normal fruit, but the firmness of ③ diseased fruit is significantly higher; the sugar content of ③ diseased fruit decreased significantly, and the taste became sour, lighter or bitter. The surface brightness of ④ diseased fruit decreased obviously, and the color uniformity became worse; on ⑤ diseased tree, there were many abnormal fruits such as pear-shaped fruit, barrel-shaped fruit, red nose fruit and green head fruit, and the fruit size and ripening condition of ⑥ diseased tree were uneven, the fruit size was large and small, and the pericarp of ⑥ diseased tree was rough and thick.

4. Symptoms of floral organ disease

The damaged citrus trees will have obvious phenomena such as early flowering, more flowering, more abnormal flowers and so on, and these flowers on the diseased trees are difficult to bear fruit in the later stage, and will wither and fall in the later stage.

5. Symptoms of root disease

The symptoms of Huanglong disease of fruit trees are mainly manifested in the branches and leaves of the aboveground parts, but in the case of serious disease, the roots of diseased fruit trees will have no new roots, decrease new roots or root rot, and even cause dead trees.

Summary of symptoms of diseased trees: the most prominent symptoms of citrus Huanglong disease are branches on fruit trees, yellow and green leaves, mottled yellowing, but it is necessary to distinguish between Huanglong disease etiolation and element deficiency etiolation (such as iron deficiency, zinc, magnesium, manganese, etc.), root diseases and insect pests (such as root nematodes, virus diseases, retting roots), fertilizer yellowing, drug yellowing and other symptoms.

The above is the introduction of citrus Huanglong disease. Citrus Huanglong disease has a high incidence, strong transmission and serious harmfulness. Farmers should grasp the above symptoms and prevent them in time to avoid unnecessary losses.

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