A method for preventing and treating citrus huanglongbing disease

Abstract

The application provides a method for preventing and treating citrus Huanglongbing, comprising a whole-year management scheme, by using corresponding pesticide combinations in different application periods, three ways of blocking the main transmission source, chemical pesticide prevention and treatment, and enhancing the growth and resistance of fruit trees are combined, and finally the effect of efficiently preventing and treating citrus Huanglongbing is achieved, and loss is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of citrus control technology, specifically relating to a method for controlling citrus Huanglongbing (HLB). Background Technology

[0002] Pyriproxyfen is a phenyl ether insect growth regulator, a novel insecticide belonging to the juvenile hormone analogue class. It is characterized by low toxicity, long-lasting effect, safety for crops and fish, and minimal impact on the ecological environment. It has good control effects on whiteflies, scale insects, diamondback moths, beet armyworms, cotton bollworms, pear psyllids, and thrips, and also provides excellent control of flies, mosquitoes, and other sanitary pests.

[0003] Citrus Huanglongbing (HLB) is caused by Bacillus phloemus (Bacillus). Candidatus Liberibacter Huanglongbing (HLB) is a Gram-negative bacterium that is obligately parasitic on the phloem. It causes citrus Huanglongbing, a major disease that seriously threatens citrus production worldwide. The bacterium is primarily transmitted by the citrus psyllid and can infect all citrus varieties and hybrids, as well as other Rutaceae plants. Infection can occur at any stage of the citrus growth cycle, ultimately leading to tree death and severe economic losses.

[0004] The citrus psyllid, belonging to the family Psyllidaceae in the order Hemiptera, is a significant pest of citrus, lemon, wampee, and Murraya paniculata, among other Rutaceae plants. The citrus psyllid infests plants by piercing and sucking their flesh. Adults disperse on leaves and buds to feed, while nymphs congregate on new shoots, buds, and leaves, causing yellowing, withering, and drying of shoots and buds, and twisting, deforming, and easily falling leaves, severely impacting plant growth.

[0005] Citrus psyllids are important vectors for the transmission of Huanglongbing (HLB) pathogen in citrus. Both adults and older nymphs can carry the pathogen and transmit it by feeding on the sap of the phloem of healthy trees. The transmission rate of a single adult psyllid can reach more than 70%. After emerging from the larvae, the psyllids can carry the pathogen for life. Rutaceae plants such as wampee and Murraya paniculata around the orchard will become shelters for the psyllids, expanding the spread of the pathogen.

[0006] The growth of citrus trees and other common citrus diseases and pests are also closely related to the occurrence of Huanglongbing (HLB). Common citrus diseases and pests can weaken the growth of citrus trees, and weak citrus trees are more susceptible to disease. Therefore, a comprehensive management plan is needed to fully control common citrus diseases and pests, enhance tree growth, and reduce the incidence of HLB.

[0007] Therefore, there is a need to provide a method that can control citrus psyllids to block the transmission route of citrus Huanglongbing (HLB) while simultaneously controlling other common pests and diseases, so as to reduce the incidence of citrus HLB and reduce losses. Summary of the Invention

[0008] Based on the above, the purpose of this invention is to provide a method for preventing and controlling citrus Huanglongbing (HLB) to solve the technical problems mentioned in the background art. The technical solution of this invention is as follows: One method for controlling citrus Huanglongbing (HLB) includes the following year-round management plan: During the pruning and orchard cleanup period in January, apply methylated and ethylated vegetable oil, 30% tetradifon bifenazate suspension at 1500 times dilution, 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the spring shoot budding period in February, apply 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% difenoconazole pyraclostrobin suspension at 1500 times dilution, 30% tetradifonium bifenazate suspension at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the budding period of spring shoots in March, apply 1000 times dilution of disodium tetraborate tetrahydrate, 1000 times dilution of liquid humic acid fertilizer, 1500 times dilution of 10% cis-cypermethrin emulsion, 2000 times dilution of 30% tebuconazole oxime ester suspension, and 500 times dilution of 65% zineb wettable powder. During the peak flowering period in April, apply gibberellin·brassinolide, water-soluble fertilizer containing macro-elements, 10% pyriproxyfen high-efficiency cypermethrin microemulsion at 1500 times dilution, 30% difenoconazole pyraclostrobin suspension at 2000 times dilution, and 50% mancozeb wettable powder. During the physiological fruit drop period in May, apply 20% abamectin chlorantraniliprole suspension at a dilution of 2000 times, 15% pyriproxyfen microcapsule suspension at a dilution of 1000 times, 40% thiophanate-methyl suspension at a dilution of 1000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the young fruit enlargement period in June, apply 20% pyriproxyfen benzoate suspension at 4000 times dilution, 40% bifenthrin thiamethoxam suspension at 2500 times dilution, 430g / L tebuconazole suspension at 2000 times dilution, or 50% mancozeb wettable powder at 500 times dilution. During the fruit enlargement period in July, apply 15% pyriproxyfen microcapsule suspension at a dilution of 2000 times, 20% acetamiprid soluble liquid at a dilution of 2000 times, 40% flutriafol and carbendazim suspension at a dilution of 3000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the fruit enlargement and autumn shoot release period in August, apply 15% pyriproxyfen microcapsule suspension at 2000 times dilution, 70% thiamethoxam water-dispersible granules at 4000 times dilution, 40% pyraclostrobin quinoline copper suspension at 1000 times dilution, and 400g / L buprofen spirodiclofen suspension at 1500 times dilution. During the autumn shoot maturation period in September, apply 20% abamectin chlorantraniliprole suspension at 2000 times dilution + 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% tebuconazole oxadiazon suspension at 2000 times dilution, and water-soluble fertilizer containing macro-elements at 1000 times dilution. During the fruit enlargement and coloring period in October, apply 10% cis-cypermethrin emulsion at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the flower bud differentiation period in November, apply 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the fruit harvesting season in December, apply 99% mineral oil at a dilution of 250 times, 3% propargite at a dilution of 1000 times, imazalil at a dilution of 1000 times, 52.5% high-chlorpyrifos at a dilution of 1000 times, and organic fertilizer.

[0009] The method described in this invention is used for the control of citrus psyllids.

[0010] The method described in this invention is used for the prevention and control of citrus Huanglongbing (HLB).

[0011] The beneficial effects of this invention are: 1. The method provided by this invention can effectively reduce the number of citrus psyllids and block the main transmission route of citrus Huanglongbing (HLB).

[0012] 2. The method provided by this invention can effectively reduce the incidence of citrus Huanglongbing (HLB) and achieve a high level of prevention and control.

[0013] 3. The method provided by this invention is a year-round management plan that can effectively prevent and control citrus diseases and pests throughout the year. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0016] Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available.

[0017] I. Preparation of 15% pyriproxyfen CS pyriproxypyr, 15%; Solvent oil 150#, 20%; Decylamide, 5%; Diphenylmethane diisocyanate, 2%; Triethylenetetramine, 0.6%; Polycarboxylate dispersant, 2.1%; Fatty alcohol polyoxyethylene ether, 0.2%; Phosphate ester dispersant, 1.5%; Organosilicon defoamer, 0.1%; BIT preservative, 0.1%; Xanthan gum, 0.2%; Ethylene glycol, 4%; Add deionized water to bring the concentration to 100%.

[0018] After dissolving pyriproxyfen, decylamide, and solvent oil, add the capsule wall material and mix thoroughly to form an oil phase. Add deionized water, dispersant, emulsifier, and a small amount of defoamer to the water phase and mix thoroughly to form an aqueous phase. Add the oil phase dropwise to the aqueous phase and shear for 20 minutes to form a mixed emulsion. Add a curing agent dropwise to the mixed emulsion, stir for 10 minutes, heat to 60°C, keep warm for 3 hours, and then stir and cool down to below 40°C to form pyriproxyfen microcapsules. Add the dispersant, thickener, antifreeze, preservative, and remaining defoamer to the pyriproxyfen microcapsules and mix thoroughly to form a pyriproxyfen microcapsule suspension.

[0019] II. Field efficacy trials Test reagents: 15% pyriproxyfen CS, 100 g / L pyriproxyfen EC (PD20131935), 30% thiamethoxam SC (PD20171450), 10% thiamethoxam CS (PD20152657), 100 g / L bifenthrin EC (PD20093514).

[0020] Test location: Xinfeng County, Ganzhou City, Jiangxi Province.

[0021] Experimental Design: The experiment consisted of 6 treatments, with 50 trees of uniform growth selected in each treatment plot. Each treatment was replicated 4 times. The specific design is as follows: Treatment 1: During the pruning and orchard cleanup period in January, apply methylated and ethylated vegetable oil, 30% tetradifon bifenazate suspension at 1500 times dilution, 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the spring shoot budding period in February, apply 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% difenoconazole pyraclostrobin suspension at 1500 times dilution, 30% tetradifonium bifenazate suspension at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the budding period of spring shoots in March, apply 1000 times dilution of disodium tetraborate tetrahydrate, 1000 times dilution of liquid humic acid fertilizer, 1500 times dilution of 10% cis-cypermethrin emulsion, 2000 times dilution of 30% tebuconazole oxime ester suspension, and 500 times dilution of 65% zineb wettable powder. During the peak flowering period in April, apply gibberellin·brassinolide, water-soluble fertilizer containing macro-elements, 10% pyriproxyfen high-efficiency cypermethrin microemulsion at 1500 times dilution, 30% difenoconazole pyraclostrobin suspension at 2000 times dilution, and 50% mancozeb wettable powder. During the physiological fruit drop period in May, apply 20% abamectin chlorantraniliprole suspension at a dilution of 2000 times, 15% pyriproxyfen microcapsule suspension at a dilution of 1000 times, 40% thiophanate-methyl suspension at a dilution of 1000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the young fruit enlargement period in June, apply 20% pyriproxyfen benzoate suspension at 4000 times dilution, 40% bifenthrin thiamethoxam suspension at 2500 times dilution, 430g / L tebuconazole suspension at 2000 times dilution, or 50% mancozeb wettable powder at 500 times dilution. During the fruit enlargement period in July, apply 15% pyriproxyfen microcapsule suspension at a dilution of 2000 times, 20% acetamiprid soluble liquid at a dilution of 2000 times, 40% flutriafol and carbendazim suspension at a dilution of 3000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the fruit enlargement and autumn shoot release period in August, apply 15% pyriproxyfen microcapsule suspension at 2000 times dilution, 70% thiamethoxam water-dispersible granules at 4000 times dilution, 40% pyraclostrobin quinoline copper suspension at 1000 times dilution, and 400g / L buprofen spirodiclofen suspension at 1500 times dilution. During the autumn shoot maturation period in September, apply 20% abamectin chlorantraniliprole suspension at 2000 times dilution + 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% tebuconazole oxadiazon suspension at 2000 times dilution, and water-soluble fertilizer containing macro-elements at 1000 times dilution. During the fruit enlargement and coloring period in October, apply 10% cis-cypermethrin emulsion at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the flower bud differentiation period in November, apply 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the fruit harvesting season in December, apply 99% mineral oil at a dilution of 250 times, 3% propargite at a dilution of 1000 times, imazalil at a dilution of 1000 times, 52.5% high-chlorpyrifos at a dilution of 1000 times, and organic fertilizer.

[0022] The difference between Treatment 2 and Treatment 1 is that the 15% pyriproxyfen CS in the treatment is replaced with 100 g / L pyriproxyfen EC, while the amount of active ingredient is the same as that of 15% pyriproxyfen CS in Treatment 1.

[0023] The difference between Treatment 3 and Treatment 1 is that the 15% pyriproxyfen CS in the treatment is replaced with 100g / L bifenthrin EC, while the amount of active ingredient is the same as that of 15% pyriproxyfen CS in Treatment 1.

[0024] The difference between Treatment 4 and Treatment 1 is that 15% pyriproxyfen CS in the treatment is replaced with 30% thiamethoxam SC, while the amount of active ingredient is the same as that of 15% pyriproxyfen CS in Treatment 1.

[0025] The difference between treatment 5 and treatment 1 is that the 15% pyriproxyfen CS in the treatment is replaced with 10% thiamethoxam CS, while the amount of active ingredient is the same as that of 15% pyriproxyfen CS in treatment 1.

[0026] The difference between treatment 6 and treatment 1 is that the 15% pyriproxyfen CS in the protocol is replaced with water as a blank control.

[0027] Citrus psyllid control efficacy survey: Surveys were conducted in August, 15 days before and after pesticide application. Five citrus trees were randomly selected from each plot. New shoots on each tree were marked at the east, west, south, north, and center. Two newly sprouted shoots at each location were designated as one counting point, for a total of 10 counting points per tree. The citrus psyllid population was recorded, and the control efficacy was calculated using the following formula:

[0028] Citrus Huanglongbing Incidence Survey: During the fruit enlargement and coloring stage, the number of diseased citrus trees in each treatment plot was investigated, and the incidence rate was calculated using the following formula:

[0029] During the field trial, both citrus psyllids and citrus Huanglongbing (HLB) were at their peak incidence. The results are shown in the table below. Treatment 1, using pyriproxyfen CS formulation, showed the highest control efficacy against psyllids (95.74%) and the lowest HLB incidence (2.50%). Treatment 2, using pyriproxyfen EC formulation, showed a control efficacy of 87.31% against psyllids and an HLB incidence of 12.00%. Treatment 3, using bifenthrin EC formulation, showed a control efficacy of 74.27% against psyllids and an HLB incidence of 24.00%. Treatment 4, using thiamethoxam SC formulation, showed a control efficacy of 70.76% against psyllids and an HLB incidence of 27.50%. Treatment 5, using thiamethoxam CS formulation, showed a control efficacy of 90.86% against psyllids and an HLB incidence of 8.00%. Treatment 6, a water control, showed an HLB incidence of 74.50%.

[0030] The above experimental results show that when the active ingredient is pyriproxyfen, the pyriproxyfen microcapsule suspension selected in this invention has a better inhibitory effect on the incidence of Huanglongbing than the pyriproxyfen emulsifiable concentrate; when the active ingredients are different but the dosage form is microcapsule suspension, the pyriproxyfen microcapsule suspension selected in this invention has a better inhibitory effect on the incidence of Huanglongbing than the thiamethoxam microcapsule suspension; the pyriproxyfen microcapsule suspension selected in this invention also has a better inhibitory effect on the incidence of Huanglongbing than other schemes that use commonly used agents (bifenthrin emulsifiable concentrate and thiamethoxam suspension).

[0031] In summary, the solution provided by this invention can more effectively block the main transmission routes of citrus Huanglongbing (HLB), thereby reducing the incidence of HLB and minimizing losses.

[0032] Table 1 Field efficacy trials

[0033] Note: The data in the table is the average of four repetitions, and the results are rounded to two decimal places.

[0034] The method for controlling citrus Huanglongbing provided by this invention increases the duration of efficacy by using the sustained-release effect of pyriproxyfen microcapsule suspension, covering the period when citrus psyllids are prevalent, thus achieving long-term pest control.

[0035] The method for controlling citrus Huanglongbing provided by this invention is a year-round management plan. By applying pyriproxyfen microcapsule suspension in combination with other agents at different application periods, it combines three methods: blocking the main source of transmission, chemical control, and enhancing the growth and resistance of fruit trees, ultimately achieving a highly effective control of citrus Huanglongbing and effectively reducing losses.

[0036] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for controlling citrus Huanglongbing (HLB), characterized in that, This includes the following year-round management plan: During the pruning and orchard cleanup period in January, apply methylated and ethylated vegetable oil, 30% tetradifon bifenazate suspension at 1500 times dilution, 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the spring shoot budding period in February, apply 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% difenoconazole pyraclostrobin suspension at 1500 times dilution, 30% tetradifonium bifenazate suspension at 1500 times dilution, and liquid humic acid fertilizer at 1000 times dilution. During the budding period of spring shoots in March, apply 1000 times dilution of disodium tetraborate tetrahydrate, 1000 times dilution of liquid humic acid fertilizer, 1500 times dilution of 10% cis-cypermethrin emulsion, 2000 times dilution of 30% tebuconazole oxime ester suspension, and 500 times dilution of 65% zineb wettable powder. During the peak flowering period in April, apply gibberellin·brassinolide, water-soluble fertilizer containing macro-elements, 10% pyriproxyfen high-efficiency cypermethrin microemulsion at 1500 times dilution, 30% difenoconazole pyraclostrobin suspension at 2000 times dilution, and 50% mancozeb wettable powder. During the physiological fruit drop period in May, apply 20% abamectin chlorantraniliprole suspension at a dilution of 2000 times, 15% pyriproxyfen microcapsule suspension at a dilution of 1000 times, 40% thiophanate-methyl suspension at a dilution of 1000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the young fruit enlargement period in June, apply 20% pyriproxyfen benzoate suspension at 4000 times dilution, 40% bifenthrin thiamethoxam suspension at 2500 times dilution, 430g / L tebuconazole suspension at 2000 times dilution, or 50% mancozeb wettable powder at 500 times dilution. During the fruit enlargement period in July, apply 15% pyriproxyfen microcapsule suspension at a dilution of 2000 times, 20% acetamiprid soluble liquid at a dilution of 2000 times, 40% flutriafol and carbendazim suspension at a dilution of 3000 times, and water-soluble calcium fertilizer at a dilution of 1000 times. During the fruit enlargement and autumn shoot release period in August, apply 15% pyriproxyfen microcapsule suspension at 2000 times dilution, 70% thiamethoxam water-dispersible granules at 4000 times dilution, 40% pyraclostrobin quinoline copper suspension at 1000 times dilution, and 400g / L buprofen spirodiclofen suspension at 1500 times dilution. During the autumn shoot maturation period in September, apply 20% abamectin chlorantraniliprole suspension at 2000 times dilution + 15% pyriproxyfen microcapsule suspension at 1000 times dilution, 30% tebuconazole oxadiazon suspension at 2000 times dilution, and water-soluble fertilizer containing macro-elements at 1000 times dilution. During the fruit enlargement and coloring period in October, apply 10% cis-cypermethrin emulsion at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the flower bud differentiation period in November, apply 15% pyriproxyfen microcapsule suspension at 1500 times dilution, 50% imazalil manganese salt wettable powder at 1500 times dilution, potassium dihydrogen phosphate at 1000 times dilution, and 25% paclobutrazol at 400 times dilution. During the fruit harvesting season in December, apply 99% mineral oil at a dilution of 250 times, 3% propargite at a dilution of 1000 times, imazalil at a dilution of 1000 times, 52.5% high-chlorpyrifos at a dilution of 1000 times, and organic fertilizer.

2. The method of claim 1 for the control of citrus psyllids.

3. The use of the method as described in claim 1 for the prevention and control of citrus Huanglongbing (HLB).

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