Huanglongbing is a devastating disease caused by fungi-like bacteria. Through the transmission of citrus psyllids, strengthening the detection and control of citrus psyllids and cutting off the transmission route are important links to prevent the epidemic of Huanglongbing.
Features and identification methods
The main symptoms of citrus greening disease are mottled yellowing on the early-stage yellow shoots of diseased trees and leaves of diseased plants. The diseased trees also have fallen leaves, irregular shoots, short and weak shoots, small leaves, and local cork cracking. The crown of the diseased tree is sparse, there are many dead branches, the plant is short, the flowers bloom early and abundant, the petals are short, thick, light yellow and dull, and the flowers on the small branches are often clustered into clusters. The pedicles of some varieties turn orange-red early, and the coloring is uneven. Fujian is commonly known as "red-nosed fruit". The root of the diseased tree is normal at the initial stage, but rotten roots appear in the later stage. The rot starts from the fibrous root and gradually rots to the large root. The xylem turns black and the root bark falls off.
Use pesticides
(1)Imidacloprid
Dosage form: 10% WP.
Control period: The prevention and control of Huanglongbing is mainly to cut off the transmission of citrus psyllids. According to the characteristics that the occurrence period of each generation of nymphs of citrus psyllid is closely related to the "three-shoot" period of spring, summer and autumn, the prevention and control technology should focus on the "three-shoot" period, which is the appropriate period for prevention and control. Generally, it is advisable to carry out the first control when the new shoots germinate until the shoots are 5 cm long. If the base of the insect population in the field is high and the shoots are uneven and the shoot period is long, the second and third times of control need to be carried out. The intervals between the second and second times of control can be 7 to 10 days. Under normal circumstances, the damage of citrus psyllid can be basically controlled by controlling once in spring, 1 to 2 times in summer, 2 to 3 times in autumn, and more than 4 times throughout the year.
Usage method: 1500-2000 times liquid of 10% imidacloprid wettable powder.
Precautions: Imidacloprid should not be mixed with alkaline pesticides or substances; beekeeping, sericulture sites and related water sources should not be polluted during use; use at the appropriate time, and use is prohibited one week before harvest.
(2) Buprofezin
Dosage form: 25% wettable powder.
Control period: Same as "imidacloprid".
Usage method: 1000-1500 times liquid of 25% Pudiling wettable powder.
Precautions: Do not use the toxic soil method with buprofezin; the liquid should not be in direct contact with cabbage and radish, otherwise symptoms of phytotoxicity such as brown spots and whitening of green leaves will occur.
(3) Phosphate
Dosage form: 40% emulsifiable concentrate.
Control period: Same as "imidacloprid".
Usage method: 40% quick culling EC 1500 times solution.
Precautions: Quick culling cannot be mixed with alkaline pesticides; quick culling should avoid spraying in the late flowering period to avoid flower damage, the best time to use is before the flowers bloom, and the concentration should not be increased arbitrarily, otherwise it will cause brown leaves spot.
(4)Abamectin
Dosage form: 1.8% emulsifiable concentrate.
Control period: Same as "imidacloprid".
Usage method: 1.8% abamectin emulsifiable concentrate 2500 times.
Precautions: When applying Abamectin, protective measures should be taken, such as wearing a mask; it is highly toxic to fish, and should avoid polluting water sources and ponds, etc.; it is highly toxic to silkworms, and mulberry leaves will still be poisoned 40 days after spraying Silkworm effect; Toxic to bees, do not apply during flowering period; last application is 20 days from harvest period.
