A pesticide composition for preventing and controlling wheat aphids

Abstract

The present invention belongs to the field of pesticides, and specifically relates to a pesticide composition for controlling wheat aphids. The present invention provides a Beauveria bassiana strain HFW-05, which is pathogenic to wheat aphids. When combined with sulfoxaflor, the composition exhibits significant synergistic effects, improving control efficacy, significantly reducing the dosage of a single chemical pesticide, reducing environmental pollution, and delaying the development of pesticide resistance in target pests. The composition has promising application prospects.

Description

Technical Field

[0001] The invention belongs to the field of pesticides, and particularly relates to a pesticide composition for preventing and controlling wheat aphids. Background Art

[0002] Beauveria bassiana is a broad-spectrum entomopathogenic fungus that parasitizes over 700 species of insects and mites from 149 families across 15 orders, including Lepidoptera, Homoptera, Hymenoptera, and Orthoptera. It boasts numerous advantages, including safety for humans and animals, minimal environmental pollution, and resistance to developing pesticide resistance. In my country, Beauveria bassiana has been used to control a variety of agricultural pests, including white grubs, corn borers, tea leafhoppers, soybean borers, potato beetles, and rice planthoppers. Studies have also identified highly virulent strains of Beauveria bassiana for controlling wheat aphids, peach aphids, and soybean aphids. However, in field applications, Beauveria bassiana, as a biopesticide, requires a long time for its spores to grow, resulting in a slow rate of action, poor rapidity, and susceptibility to environmental influences. This often fails to achieve optimal control results, particularly against rapidly developing and reproducing pests such as aphids.

[0003] Sulfoxaflor is a sulfonimide insecticide that acts on the insect nervous system, specifically at unique binding sites within cholinergic receptors. It is suitable for controlling piercing-sucking pests such as blind bugs, aphids, planthoppers, and scale insects. It boasts high efficacy, low toxicity, low residual activity, good systemic properties, and safety against non-target organisms. However, the development of sulfoxaflor resistance in some pests, such as cotton aphid, has become a significant concern.

[0004] Combining chemical insecticides with entomogenous fungi not only mitigates the slow rate of fungal infection, shortening pest control time and improving insecticide efficiency, but also overcomes or delays the development of insecticide resistance, reduces chemical dosage, and reduces chemical pollution. Therefore, screening for low-dose combinations of sulfoxaflor and Beauveria bassiana is of great significance for effectively controlling pests and mitigating insecticide resistance. Summary of the Invention

[0005] To solve the above problems, the present invention provides a pesticide composition comprising sulfoxaflor and Beauveria bassiana.

[0006] Furthermore, the present invention provides an application of Beauveria bassiana in preventing and controlling wheat aphids. When used, the Beauveria bassiana is used in the form of conidia, preferably in the form of a suspension or spore powder. The final concentration of the Beauveria bassiana is 6×10 6 ~4×10 7 spores / mL, preferably 6×10 6 ~1×10 7 spores / mL.

[0007] Furthermore, in order to achieve better control effects, the combination of sulfoxaflor and Beauveria bassiana HFW-05 can produce significant synergistic effects and have a significant control effect on wheat aphids. The final concentration of sulfoxaflor is 0.01-0.025 mg / mL, preferably 0.01-0.013 mg / mL. Preferably, the ratio of sulfoxaflor to Beauveria bassiana is 0.01-0.013 mg / mL: 6×10 6 ~1×10 7 spores / mL, and more preferably the ratio of sulfoxaflor to Beauveria bassiana is 0.01 mg / mL: 6×10 6 spores / mL.

[0008] The present invention also provides the use of the above insecticide combination in controlling wheat aphids, which significantly improves the control effect, significantly reduces the dosage of chemical pesticides, reduces environmental pollution, and effectively solves the problem of pesticide resistance. DETAILED DESCRIPTION

[0009] Various exemplary embodiments of the present invention are now described in detail. Unless otherwise specified, the methods in the examples are conventional methods. Unless otherwise specified, the reagents used are conventional commercially available reagents or reagents prepared using conventional methods. This detailed description should not be considered a limitation of the present invention, but rather should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0010] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0011] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0012] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0013] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0014] The Beaueria bassaria (Balsamo) Vuillemin strain HFW-05, described in this invention, belongs to the order Combretales and genus Beauveria. It was isolated and preserved by the Insecticidal Microbiology Laboratory of the Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences. This dominant strain has strong toxicity against pests such as whiteflies, diamondback moths, and cotton bollworms. It exhibits rapid insecticide activity, is safe against natural enemies, and is environmentally friendly.

[0015] Example 1 Indoor toxicity determination of Beauveria bassiana and sulfoxaflor against Aphididae

[0016] The test subjects were adult wheat aphids (Sitobion avenae);

[0017] The test agents were Beauveria bassiana, sulfoxaflor, and a mixture of these two agents. The Beauveria bassiana strain was Beauveria bassiana HFW-05, provided by the Insecticidal Microbiology Laboratory, Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences. Sulfoxaflor was the technical product of sulfoxaflor (Corteva Agricultural Technology Co., Ltd.).

[0018] Indoor toxicity determination, take a small amount of spore powder and put it into sterilized Tween 80 solution to prepare spore suspension, observe and adjust under a microscope, and prepare 4×10 7 , 2×10 7 , 1×10 7 , 0.5×10 7 , 0.25×10 7spores / mL. Sulfoxaflor agents were respectively prepared into gradient solutions of 100, 50, 25, 12.5, and 6.25 mg / L with Tween 80 solution. The bioassay was carried out by the leaf immersion method recommended by FAO (1980). The wheat leaves with aphids were immersed in the liquid medicine of different concentrations for 10 s, taken out and dried, placed in a petri dish with the reverse side up, and at room temperature (22 ± 2)°C, the number of dead aphids was checked after 4 d. When checking, the insect body was stirred with a small brush, and the test insect was regarded as dead if it did not move at all. An aqueous solution of Tween 80 was used as a control, with 30 insects treated at each concentration and 3 replicates. Using DPS v6.55 software, the toxicity regression equation (Y = A + BX), median lethal concentration LC 50 value and 95% confidence interval were calculated based on the mortality probability value and the logarithm of the concentration. The LC50 of Beauveria bassiana and sulfoxaflor against Sitobion avenae were 1.55×10 7 spores / mL and 12.29 mg / L respectively.

[0019] Example 2 Screening of synergistic combination of sulfoxaflor and Beauveria bassiana

[0020] According to Example 1, the two single agents were respectively prepared into certain concentrations. The Beauveria bassiana spore suspension was set at 4×10 7 , 1×10 7 and 1×10 6 spores / mL at 3 concentrations, and the final concentrations of the insecticides were 0.01, 0.013, 0.017, and 0.025 mg / mL respectively. The two single agents were prepared into a mixed liquid medicine, and the concentrations of each single agent in the mixed liquid medicine were the same as those when they were used alone. The indoor toxicities of each single agent and the mixture to the test insects were measured respectively.

[0021] The theoretical mortality rate (P m ) = 1 - (1 - P A ) × (1 - P B )

[0022] P A , P B are respectively the mortality rates of the test insects of each single agent. The combined action of the two agents in combination was qualitatively judged by the size of the cf (synergistic toxicity index) value.

[0023] <于 <于 <于

[0024] When cf ≥ 20, it is a synergistic effect; when cf ≤ -20, it is an antagonistic effect; when -20 < cf < 20, it is an additive effect.

[0025] Adult aphids of the wheat stem were tested in a laboratory with various concentrations and combinations of sulfoxaflor and Beauveria bassiana. The synergistic toxicity index (cf) was used to evaluate whether different combinations of sulfoxaflor and Beauveria bassiana had synergistic effects. The results (Table 1) showed that the ratio of sulfoxaflor to Beauveria bassiana was 0.013 mg / mL: 6 × 10 6 spores / mL, 0.01 mg / mL: 6×10 6 spores / mL, 0.01mg / mL: 1×10 7 spores / mL, all showed synergistic effects, and their cf values ​​on 4 days reached 22.68, 51.79, and 23.68, respectively.

[0026] Table 1 Synergistic toxicity index (cf) of sulfoxaflor and Beauveria bassiana mixed against Aphididae

[0027]

[0028]

[0029] Example 3 Field control effect of the optimal ratio of sulfoxaflor and Beauveria bassiana

[0030] According to Example 2, the combination with the highest synergistic toxicity index was selected: sulfoxaflor: Beauveria bassiana at 0.01 mg / mL: 6×10 6 The field spray test was conducted with 50% sulfoxaflor water-dispersible granules (from Corteva Agricultural Technology Co., Ltd.). The test crop was winter wheat, and the field wheat aphids were a mixed population of Macrosiphum aestivum, Schizaphis graminis, and Rhizopus graminis. The experiment used a completely randomized design with three replicates per treatment and a water control. Each plot was 20 m2. 2 , a 5-point sampling method was used, with 5 plants at each point for fixed-point investigation. The number of wheat aphids was investigated before, 1, 3, and 7 days after application, and the insect population reduction rate and control effect were calculated.

[0031] Insect population reduction rate (%) = (number of insects before medication - number of insects after medication) / number of insects before medication × 100%

[0032] Control effect (%) = (insect population reduction rate in the treated area - insect population reduction rate in the control area) / (1 - insect population reduction rate in the control area) × 100%

[0033] The DPS software was used for statistical analysis, and the Duncan's new multiple range method was used for statistical analysis of the control effect of each treatment.

[0034] In terms of field efficacy (Table 2), significant differences were observed between the three treatments in terms of control efficacy against wheat aphids. The efficacy of the combined treatment was above 94% at 1, 3, and 7 days after application, significantly higher than that of Beauveria bassiana and sulfoxaflor alone. This indicates that the ratio of sulfoxaflor to Beauveria bassiana was 0.01 mg / mL:6 × 10 6 The compound combination with spores / mL had a significant synergistic effect.

[0035] Table 2 Control effect of Beauveria bassiana HFW-05 and sulfoxaflor on wheat aphids

[0036]

Claims

1. An application of a pesticide composition for controlling wheat aphids, characterized in that: The pesticide composition comprises sulfoxaflor and Beauveria bassiana; The Beauveria bassiana is Beauveria bassiana HFW-05; The ratio of sulfoxaflor and Beauveria bassiana is 0.01 mg / mL: 6×10 6 spores / mL, 0.013 mg / mL: 6×10 6 spores / mL or 0.01 mg / mL: 1×10 7 spores / mL.

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