Use of a thiazole copper and a polyglucosan composition

Abstract

This invention relates to the application of a thiazolium copper and glucan composition for the control of citrus Huanglongbing (HLB), belonging to the field of biotechnology. The application of the glucan composition of this invention in the control of citrus HLB shows significant effects on the control of HLB and the recovery of citrus tree vigor. The glucan and thiazolium copper suspension have a synergistic effect, which can improve the control efficacy of citrus HLB, reduce the dosage, reduce the number of applications, and lower the cost.

Description

Technical Field

[0001] This invention relates to the application of a glucan in the control of citrus Huanglongbing (HLB), and belongs to the field of biotechnology. Background Technology

[0002] Citrus Huanglongbing (HLB) is a quarantine disease caused by the difficult-to-culture Candidatus Liberibacter spp. It is characterized by its long incubation period, rapid spread, and wide range of damage.

[0003] This disease poses a serious challenge to the global citrus industry. In my country, it has affected approximately 300 counties in 11 provinces, causing damage to a large number of citrus trees and a significant decline in both yield and quality, severely hindering the healthy development of the industry.

[0004] Control measures for citrus Huanglongbing (HLB) mainly include spraying pesticides to kill the vector insect psyllid, cutting down diseased trees, and cultivating virus-free seedlings. However, these methods have significant limitations. While insect-proof netting can effectively isolate psyllids, its high cost limits its widespread application and is not conducive to mechanized and intelligent management. Chemical control is effective in the short term, but it easily leads to increased pesticide resistance in psyllids, while also causing pesticide residues and ecological damage. Antibiotic control may cause phytotoxicity, affecting fruit appearance, and long-term use can enhance pathogen resistance, making the disease prone to recurrence after discontinuation of treatment.

[0005] Although some patents have disclosed the use of antibiotics to prevent Huanglongbing (HLB) in citrus, such as ZL2020114331857 which discloses a method for preventing HLB using avibactam and β-lactam antibiotics; L2016104590191 which discloses a method for controlling HLB by injecting ampicillin and cyclopentylpiperazine-rifamycin into the trunk; and Zl2016102156210 which discloses a method for treating HLB by injecting streptomycin, tebufenozide hydrochloride, α-naphthaleneacetic acid, and salicylic acid into the trunk, these methods typically require the use of antibiotics and trunk injection. However, the use of antibiotics can easily lead to antibiotic residues in citrus fruits and antibiotic resistance due to overuse. Furthermore, trunk injection is inconvenient for farmers to perform, greatly limiting the application of these methods.

[0006] CN119157016A discloses a method for repairing citrus trees affected by Huanglongbing (HLB), relating to the field of plant cultivation technology. The method employs a combination of trunk infusion and foliar spraying for treating HLB-infected citrus trees. The first trunk infusion begins in mid-to-late May, with subsequent infusions spaced no more than one month apart. Foliar spraying, depending on weather conditions, involves applying fungicides and insecticides to the leaves approximately 15 days after each trunk infusion, for a total of four applications. This invention achieves stable repair results by selecting suitable pesticide combinations and simultaneously setting reasonable timing and frequency for both trunk infusion and foliar spraying, using them alternately. This method utilizes a combination of multiple antibiotic trunk infusions and various foliar sprays. Summary of the Invention

[0007] The technical problem solved by this invention is to propose a composition of thiazolium copper and glucan hexasaccharide and its application in the control of citrus Huanglongbing (HLB), which shows significant effects on the control of HLB and the recovery of citrus tree vigor. The glucan hexasaccharide and thiazolium copper suspension have a synergistic effect, which can improve the control effect of citrus HLB, reduce the dosage, reduce the number of applications, and reduce the cost. After citrus seedlings are transplanted, the composition can be applied by root irrigation or spraying, both of which have a control effect on citrus HLB.

[0008] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is: a thiazolium copper and glucan composition for the prevention and control of citrus Huanglongbing, the composition comprising the following active ingredients: 20% thiazolium copper suspension and glucan;

[0009] The structural formula of the dextran hexasaccharide is as follows:

[0010]

[0011] The application of the glucan hexasac composition for controlling citrus Huanglongbing in the preparation of agents for controlling citrus Huanglongbing.

[0012] Preferably, the thiazolium copper and glucan composition used for the prevention and control of citrus Huanglongbing (HLB) has a glucan concentration of 3 mg / L-5 mg / L and a 20% thiazolium copper suspension concentration of 1.9-3.8 ml / L.

[0013] Preferably, the thiazole copper and glucan composition used for the prevention and control of citrus Huanglongbing (HLB) has a glucan concentration of 5 mg / L and a 20% thiazole copper suspension concentration of 3.8 ml / L.

[0014] Preferably, the thiazolium copper and glucan composition used for the prevention and control of citrus Huanglongbing (HLB) has a glucan concentration of 3.33 mg / L and a 20% thiazolium copper suspension concentration of 2.5 ml / L.

[0015] To solve the above-mentioned technical problems, another technical solution proposed by the present invention is: the application of the thiazole copper and glucan composition for the prevention and control of citrus Huanglongbing in the prevention and control of citrus Huanglongbing.

[0016] Preferably, the composition is applied by root irrigation or spraying after citrus seedlings have been transplanted, which has a preventive effect against citrus Huanglongbing.

[0017] The beneficial effects of this invention:

[0018] The composition for controlling citrus Huanglongbing (HLB) of this invention exhibits a significant synergistic effect when combined with glucan and copper thiazole suspension, significantly enhancing its control efficacy against HLB. Using glucan or copper thiazole suspension alone yields little effect against HLB. Applying the composition after citrus seedling transplantation, either through root irrigation or spraying, demonstrates its effectiveness in controlling HLB.

[0019] As shown in Table 1, after 3 months of root irrigation treatment with 3.8 ml / L of 20% copper thiazole suspension and 5 mg / L of dextran, the disease index was 6.7 and the control effect was 88.3%. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is a diagram showing the effect of combining glucan and thiazole copper suspension in the control of citrus Huanglongbing (HLB).

[0022] Figure 2 This is a diagram showing the effect of combining glucan and thiazole copper suspension in the control of citrus Huanglongbing (HLB). Detailed Implementation

[0023] Example 1:

[0024] In mid-August 2024, a field efficacy trial of the herbicide was conducted in a navel orange orchard in Wenwuba Town, Huichang County, Ganzhou City, Jiangxi Province. The trees in the orchard were 4 years old. The occurrence of citrus Huanglongbing (HLB) was investigated at the end of September and mid-October. The disease occurrence was classified according to the degree of yellowing of the leaves, and the disease index and control effect were calculated. The results are shown in Table 1.

[0025] Table 1

[0026]

[0027] The water consumption for spraying is 1.5L; the water consumption for root irrigation is 2L per tree.

[0028] The 20% thiazole copper suspension was purchased from Zhejiang Longwan Chemical Co., Ltd.

[0029] Conclusion: As shown in Table 1, after 3 months of root irrigation treatment with 3.8 ml / L of 20% copper thiazole suspension and 5 mg / L of dextran, the disease index was 6.7 and the control effect was 88.3%.

[0030] The combination of thiazole copper suspension and glucan, when applied as a root irrigation treatment, showed significant control effects against citrus Huanglongbing (HLB). However, the use of thiazole copper suspension or glucan alone was not effective against HLB.

[0031] Application method

[0032] Spraying: First, dilute the pesticide according to the specified method. Then, use a drone equipped with a sprayer to evenly spread the pesticide onto the crops according to the final concentration in the table.

[0033] Root irrigation: Dig a circular pit 10 cm deep at the base of the tree, pour the pesticide into the pit, and then cover the pit with soil.

[0034] Table 2 Grading Criteria for Huanglongbing

[0035]

[0036] Example 2

[0037] On March 20, 2025, during the peak flowering period of navel oranges, a field efficacy trial of Huanglongbing (HLB) in navel orange orchards was conducted in Longtang Town, Dingnan County, Ganzhou City, Jiangxi Province. Treatment 1 involved spraying with 3 ml / L of 20% thiamethoxam suspension plus 4 mg / L of glucan, while Treatment 2 involved drenching the roots with 2.5 ml / L of 20% thiamethoxam suspension plus 3.33 mg / L of glucan, using 12.5 kg of water per tree. A control group was treated with plain water spraying. On May 15, a survey revealed that most leaves in both spraying and drenching treatments remained green with no obvious yellowing symptoms. Only a few navel oranges showed yellowing leaves on a few branches. Treatment 1 had a disease index of 1.6, with a control effect of 96.7%, while Treatment 2 had a disease index of 1.4, with a control effect of 97.2%. The control group had a disease rate of 100%, with disease levels of 2 or 3, and an average disease index of 48.1.

[0038] The combination of thiazole copper suspension and glucan hexasaccharide, applied by root irrigation or spraying, has a significant preventive effect against citrus Huanglongbing (HLB), with a control effect of over 96.7%.

[0039] Example 3

[0040] In 2025, a field efficacy trial of herbicides against Huanglongbing (HLB) in navel oranges was conducted in Yudu County, Ganzhou City, Jiangxi Province. The orchard was abandoned, with trees aged 5 years, and had been unmanaged since 2024. The HLB incidence rate in the orchard was 100%. Except for the control group, all trees in the orchard were treated with a root drench using 20% ​​thiamethoxam suspension (2.5 ml / L) plus glucan (3 mg / L), with 12.5 kg of water per tree. A root drench with plain water served as a control. Treatment 1 was applied once each in mid-May, late June, and late August, while Treatment 2 was applied once each in mid-May and late June. A survey on October 24th found that Treatment 1, after three applications, reduced fruit drop by 91.8%, while Treatment 2, after two applications, reduced fruit drop by 68.5%. A survey at the end of November found that the HLB incidence rate in the control group was 100% (including red-nosed and green-stunted fruits), while the HLB incidence rate in the treated areas ranged from 0% to 15%, with an average of 7.8%. The combination of thiazole copper suspension and glucan hexasaccharide, when applied as a root irrigation treatment, has a significant preventive effect against citrus Huanglongbing (HLB), reducing fruit drop rate by more than 68.5%.

[0041] Example 4

[0042] In 2025, a field efficacy trial of a pesticide was conducted in a navel orange orchard in Xiaomi Township, Huichang County, Ganzhou City, Jiangxi Province. This orchard consisted of trees approximately 20 years old, located in a low-lying area, experiencing annual frosts, and exhibiting poor tree vigor. Each year, 5%-10% of the trees were felled due to severe Huanglongbing (HLB), resulting in a 100% HLB incidence rate. The orchard was treated twice, once in mid-May, once in late June, and once in late August, with the pesticide consisting of 20% thiamethoxam suspension (2.5 ml / L) plus 3.33 mg / L glucan. On November 5th, 3.33 mg / L of glucan was applied as a root drench along with water-soluble fertilizer. A survey at the end of November revealed that the HLB incidence rate in the treatment area was 57.6%, with a HLB fruit rate of 2.6%, while the control area had a 100% HLB incidence rate and a HLB fruit rate of 45.9%. The experimental results are detailed below. Figure 1 .

[0043] The combination of thiazole copper suspension and glucan hexasaccharide, when applied as a root irrigation treatment, showed significant control effects against citrus Huanglongbing (HLB), with the HLB incidence rate dropping to only 2.6%.

[0044] The present invention is not limited to the specific technical solutions described in the above embodiments. All technical solutions formed by equivalent substitutions are within the scope of protection claimed by the present invention.

Claims

1. The application of a composition of thiazolium copper and dextran hexasaccharide, characterized in that: The composition comprises the following active ingredients: 20% copper thiazole suspension and dextran hexasaccharide by mass fraction; The structural formula of the dextran hexasaccharide is as follows: ； The thiazole copper and dextran hexasaccharide composition is used to prepare a drug for the prevention and control of citrus Huanglongbing (HLB).

2. The application of the thiazolyl copper and dextran hexasaccharide composition according to claim 1, characterized in that: The concentration of the dextran hexasaccharide is 3 mg / L-5 mg / L; The concentration of the 20% thiazole copper suspension is 1.9-3.8 ml / L.

3. The application of the thiazolyl copper and dextran hexasaccharide composition according to claim 1, characterized in that: The concentration of the dextran hexasaccharide is 5 mg / L; The concentration of the 20% thiazole copper suspension is 3.8 ml / L.

4. The application of the thiazolyl copper and dextran hexasaccharide composition according to claim 1, characterized in that: The concentration of the dextran hexasaccharide was 3.33 mg / L; The concentration of the 20% thiazole copper suspension is 2.5 ml / L.

5. The application of the thiazolyl copper and dextran hexasaccharide composition according to claim 4, characterized in that, After citrus seedlings are planted, applying the composition by root irrigation or spraying can effectively control citrus Huanglongbing (HLB).

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