Insecticidal composition and use

Abstract

The present application provides a kind of insecticidal composition and application, and the active ingredient of the insecticidal composition is Java Cordyceps and Beauveria bassiana, and the spore concentration ratio of the Java Cordyceps and Beauveria bassiana is (1-13) million spores / gram :(5-1) million spores / gram.The present application finds that the Java Cordyceps and Beauveria bassiana have significant synergistic effect by experiment, and have good quick-acting and persistence, overcome the defects of biological pesticide, such as poor quick-acting, slow prevention and control effect, high cost and the like, and have strong creativity.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to an insecticidal composition with Cordyceps militaris and Beauveria bassiana as the main active ingredients for controlling the citrus inchworm. Background Technology

[0002] The tung oil looper (Buzura suppressaria Guenee), belonging to the Geometridae family, is a leaf-eating pest within the Geometridae order of Lepidoptera. The larvae have a wide diet and primarily damage economic forests such as tung trees. In recent years, it has begun to cause serious infestations on citrus trees. The tung oil looper typically has four generations per year on citrus trees, with overlapping instars being common. The adults are strongly attracted to light and mostly emerge at night, while during the day they roost on the trunks of tall trees around tea gardens or on the walls of buildings. When startled, they either fall to the ground and feign death or fly short distances. Infestations occur extremely rapidly, cause severe damage, and are extremely difficult to control, seriously impacting public health and farmers' income. Currently, there are no registered pesticides specifically for the citrus tung oil looper.

[0003] Currently, the control of plant pests still relies primarily on conventional chemical methods. Long-term use of chemical pesticides has led to a series of problems, including the death of natural enemy insects, increased pesticide resistance, excessive pesticide residues, and environmental pollution. Biological control, due to its advantages of being green, environmentally friendly, and having a long-lasting effect, has become the most effective and promising method for pest control. Biological control is a technique that uses beneficial organisms and their products to control harmful organism populations, shifting the dynamic balance between organisms in a direction favorable to agricultural production. Therefore, seeking effective biological control products and application technologies, especially natural microbial strains, is one of the main research directions for sustainable pest control in the future.

[0004] Loopers primarily feed on leaves, consuming large quantities and exhibiting rapid outbreaks. If not carefully observed or controlled in a timely manner, they can devour all the leaves from a tree within 1-2 days. They then descend on silken threads and are carried by the wind to other trees to continue their damage. This significantly impacts tree production and environmental aesthetics, and poses a considerable threat to passersby. Conventional chemical pesticides have developed high resistance, resulting in poor efficacy. Microbial inoculants, due to their slower onset of action, often show less than 50% effectiveness within 10 days, leading to large-scale outbreaks before effectively killing the loopers, making their application less effective. The tung oil looper's outbreak rate is among the fastest of all locator moth pests. The larvae feed on leaves, sometimes completely stripping the tree bare, leaving only veins or causing bald branches resembling burnt branches, and their ability to spread to other trees exacerbates the damage.

[0005] Beauveria bassiana, belonging to the phylum Ascomycota, order Hypocreales, family Cordycepsaceae, and genus Beauveria, is a very important biocontrol fungus. It is effective against corn borers, pine caterpillars, and aphids, but its effectiveness against rapidly spreading geometrid moths has not yet been reported.

[0006] Cordyceps amyloliquefaciens, internationally known as Isaria javanica, belongs to the family Hyphomycetaceae. It is isolated from diseased and dead whiteflies. Its conidia, upon contact with the insect body, enter and multiply under suitable conditions, damaging tissues and organs, secreting toxins / secondary metabolites, affecting the insect's hemolymph, and interfering with metabolism, thereby killing the pest. Currently, it is mainly used for whiteflies, aphids, and other homoptera pests, but there are no reports proving its efficacy against geometrid moths.

[0007] Currently, both technical materials and formulations of *Cordyceps militaris* and *Beauveria bassiana* are registered and marketed. For example, Hebei Zhongbaolv Agricultural Technology Co., Ltd. has registered a 15 billion spores / g wettable powder of *Beauveria bassiana* (registration certificate number PD20183086) for use against corn armyworm; the Jiangsu Academy of Agricultural Sciences Plant Protection Institute has obtained registrations for the technical material *Cordyceps militaris* JS001 (registration certificate number PD20211356) with 50 billion spores / g and the dispersible oil suspension *Cordyceps militaris* JS001 (registration certificate number PD20211369) with 5 billion spores / mL. For formulations used to control whiteflies on tomatoes (in protected cultivation), the recommended dosage is 300–375 mL / hm². 2 Apply by spraying (20-25 mL / mu).

[0008] Both Beauveria bassiana and Cordyceps militaris are natural microbial species. The combined action mechanism of the two is relatively new and is not prone to resistance. They are highly safe and pose no risk of environmental pollution, thus filling the gap in the control of citrus tung oilworm. Summary of the Invention

[0009] The purpose of this invention is to provide an insecticidal composition for controlling the citrus looper moth, which is a compound of Cordyceps militaris and Beauveria bassiana, and can reduce the amount of conventional chemical agents used and slow down the development of resistance.

[0010] The technical solution of the present invention is as follows:

[0011] An insecticidal composition, wherein the active ingredients of the insecticidal composition are *Cordyceps militaris* and *Beauveria bassiana*, wherein the spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is 1-13:5-100 million spores / gram.

[0012] In the insecticidal composition, the preferred spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is 700 million spores / g: 300 million spores / g.

[0013] The insecticidal composition further includes adjuvants, wherein the content of the active ingredient is 1 to 20 billion spores / gram.

[0014] Specifically, the content of Cordyceps militaris is 100 million to 1.3 billion spores / gram, and the content of Beauveria bassiana is 500 million to 100 million spores / gram.

[0015] In a further embodiment, the insecticidal composition of the present invention is in the form of a suspension concentrate.

[0016] In a further embodiment, the adjuvants in the suspension of the insecticidal composition are: sodium lignosulfonate 1-4 wt%, sodium dodecyl sulfate 1-5 wt%, xanthan gum 0.04-1 wt%, sodium benzoate 0.8-3 wt%, ethylene glycol 0.8-5 wt%, and water to make up to 100 wt%.

[0017] Another objective of this invention is to provide the application of the above-described insecticidal composition in the control of the citrus inchworm.

[0018] Through experiments, this invention has shown that the combination of Cordyceps militaris and Beauveria bassiana has a significant synergistic effect, resulting in excellent control and reducing the amount of chemical pesticides used, thus reducing environmental pollution. Detailed Implementation

[0019] Through extensive indoor screening experiments, the inventors discovered that a mixture of Cordyceps militaris and Beauveria bassiana has a synergistic effect on Citrus tung oilworm.

[0020] To better understand the essence of the invention, the technical content of the invention will be described in detail below with examples. However, the content of the invention is not limited thereto and should not be construed as a limitation on the scope of the patent.

[0021] Experimental Example 1:

[0022] The test subject was the citrus inchworm.

[0023] The test agents were *Cordyceps militaris*, *Beauveria bassiana*, and a mixture of *Cordyceps militaris* and *Beauveria bassiana*. Among them, the *Cordyceps militaris* technical material JS001, with a content of 50 billion spores / gram, was obtained from the Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, with registration certificate number PD20211356.

[0024] The technical grade of Beauveria bassiana, with a content of 50 billion spores / gram, is sourced from Anhui Heibaogong Pest Control Co., Ltd., with registration certificate number PD20160104.

[0025] The experimental methods were based on the People's Republic of China agricultural industry standards "Guidelines for Indoor Bioassay of Pesticides" (Insecticides NY / T1154.2-2006 - Insecticides - Part 2 - Stomach Poison Activity Test - Leaf-clamping Method) and NY / T1154.7-2006 (Indoor Bioassay of Pesticides - Insecticides - Part 7: Determination of Combined Effects of Mixtures). The leaf-clamping method was used. The tested strains and their mixtures were prepared into 1×10⁻⁶ samples. 7 1 spores / mL, 1.0 × 10 6 1.5 × 10⁶ spores / mL 5 1 spores / mL, 1×10 4 1 spores / mL, 1×10 3 The bacterial suspension containing 1 spore / mL was statistically analyzed using DPS data processing software to calculate the LC50, LC90, standard error of b value, and 95% confidence limit of each agent, thereby evaluating the activity of the tested agents.

[0026] The co-toxicity coefficient (CTC value) of the mixture is calculated using the following formula:

[0027] CTC = AT1 / TTI * 100%

[0028] Where AT1 = S / M * 100%, TTI = TIA * PA + TIB * PB

[0029] In the formula:

[0030] CTC – Cotoxicity coefficient; AT1 – Measured toxicity index of the mixture; TTI – Theoretical toxicity index of the mixture;

[0031] The LC50 of S-standard insecticides is expressed in μg / ml.

[0032] The LC50 of the M-mixture is expressed in μg / ml.

[0033] TIA-A drug toxicity index;

[0034] The percentage content of PA-A agent in the mixture, in %;

[0035] TIB-B toxicity index;

[0036] The percentage content of PB-B agent in the mixture, in %.

[0037] Using Beauveria bassiana as the standard fungicide, the co-toxicity coefficient (CTC) of the mixture ≥120 indicates a synergistic effect; CTC ≤80 indicates an antagonistic effect; and 80 < CTC < 120 indicates an additive effect.

[0038] Table 1: Toxicity test results of each single agent and its mixture against the citrus looper moth at 7 days.

[0039]

[0040] The results are shown in Table 1. The indoor toxicity test results showed that the LC50 values ​​of *Cordyceps militaris* and *Beauveria bassiana* against *Citrus medica* were 47.2475 × 10⁻⁶, respectively. 4 Spores / mL, 21.2079*10 4 Spores / mL. When the spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is 13:1-1:5 (i.e., the spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is (1-13) billion spores / g : (5-1) billion spores / g), the co-toxicity coefficient (CTC) is much greater than 120, indicating that all the above ratios have a synergistic effect. In particular, when the spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is 7:3 (i.e., the spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* is 700 million spores / g : 300 million spores / g), the co-toxicity coefficient (CTC) is the largest, and the synergistic effect is significant.

[0041] Example 2

[0042] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 2 below by mass percentage:

[0043] Table 2. Dosage ratio of each component in the insecticidal composition.

[0044] Java Cordyceps 1.3 billion spores / gram Beauveria bassiana 100 million spores / gram Sodium lignosulfonate 1.2％ Sodium dodecyl sulfate 3.3％ Xanthan Gum 0.25％ Sodium benzoate 1.2％ Ethylene glycol 2.7％ water Make up the surplus

[0045] Example 3

[0046] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 3 below by mass percentage:

[0047] Table 3. Dosage ratio of each component in the insecticidal composition.

[0048] Java Cordyceps 1 billion spores / gram Beauveria bassiana 200 million spores / gram Sodium lignosulfonate 2.3％ Sodium dodecyl sulfate 2.8％ Xanthan Gum 0.36％ Sodium benzoate 2.35％ Ethylene glycol 2.9％ water Make up the surplus

[0049] Example 4

[0050] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 4 below by mass percentage:

[0051] Table 4. Dosage ratio of each component in the insecticidal composition

[0052] Java Cordyceps 700 million spores / gram Beauveria bassiana 300 million spores / gram Sodium lignosulfonate 1.1 Sodium dodecyl sulfate 1.32 Xanthan Gum 0.04 Sodium benzoate 0.9 Ethylene glycol 0.8 water Make up the surplus

[0053] Example 5

[0054] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 5 below by mass percentage:

[0055] Table 5. Dosage ratio of each component in the insecticidal composition.

[0056] Java Cordyceps 800 million spores / gram Beauveria bassiana 800 million spores / gram Sodium lignosulfonate 3.9 Sodium dodecyl sulfate 3.1 Xanthan Gum 0.93 Sodium benzoate 2.2 Ethylene glycol 4.6 water Make up the surplus

[0057] Example 6

[0058] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 6 below by mass percentage:

[0059] Table 6. Dosage ratio of each component in the insecticidal composition.

[0060]

[0061]

[0062] Comparative Example 1

[0063] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 7 below by mass percentage:

[0064] Table 7. Dosage ratio of each component in the insecticidal composition.

[0065] Beauveria bassiana 1 billion spores / gram Sodium lignosulfonate 1.1 Sodium dodecyl sulfate 1.32 Xanthan Gum 0.04 Sodium benzoate 0.9 Ethylene glycol 0.8 water Make up the surplus

[0066] Comparative Example 2

[0067] This embodiment provides an insecticidal composition suspension, the components of which are shown in Table 8 below by mass percentage:

[0068] Table 8. Dosage ratio of each component in the insecticidal composition.

[0069]

[0070]

[0071] Example 7: Field efficacy trial

[0072] Experimental method: Experimental location: Zaolin Ecological Park, Xiaomiao Town, Hefei City, Anhui Province, 31.84°N, 116.99°E.

[0073] Water and fertilizer management at the experimental site: Winter fertilizer was applied on December 10, 2021, mainly farmyard manure, about 5 kg per tree, supplemented with compound fertilizer (N:P:K = 15%:15%:15%), 0.5 kg per tree. On June 10 and July 21, 2022, urea was applied in holes at 0.75 kg per tree respectively. Weeding and other field management were carried out as usual.

[0074] The experimental target was the citrus inchworm.

[0075] The test agents were Examples 2-6, Comparative Examples 1-2, and the conventional chemical agent 24% biphenyl·spirotetramat suspension (bifenthrin 4% + spirotetramat 20%) as Comparative Example 3, all of which were produced and prepared by Anhui Fengle Agricultural Chemical Co., Ltd.

[0076] The application method was conventional spraying, and the application date was September 14, 2022.

[0077] Efficacy survey: Two surveys were conducted, 10 days and 15 days after application. Two fruit trees were surveyed in each plot. Five short branches were fixed in five directions on each tree. The number of active insects on 10 leaves of each branch was randomly surveyed to calculate the control effect.

[0078] Methods for calculating drug efficacy

[0079] The protective effect is calculated according to formulas (1) and (2):

[0080]

[0081]

[0082] The dosage and efficacy of the tested agents are shown in the table below:

[0083]

[0084] The test results in the table show that, in all five embodiments of the present invention, the efficacy of a 10g / mu dosage can reach over 70% after 10 days and over 80% after 15 days. Among them, the control effect of the formulation in Example 4, with a dosage of 10g / mu, is the best in both 10 and 15 days, with efficacy of 88.1% and 92.3%, respectively, which is significantly better than the efficacy of the formulations in Comparative Examples 1-3.

[0085] Field observations showed that both the tested and control pesticides were safe for the citrus crop, and no phytotoxicity symptoms (such as dwarfing, chlorosis, or deformity) were observed.

[0086] The test results of the examples show that the compound biological pesticide formulation of Cordyceps militaris-Beauveria bassiana in this invention has higher efficacy than the chemical agent 24% Biphenyl·Spirotiarin suspension in Comparative Example 3 in both short-term and long-term control. It has both good rapid effect and long-term effect, and overcomes the disadvantages of biological pesticides such as poor rapid effect, slow control effect and high cost. It has strong inventiveness.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An insecticidal composition, characterized in that: The active ingredients of this insecticidal composition are Cordyceps militaris and Beauveria bassiana, wherein the spore concentration ratio of Cordyceps militaris to Beauveria bassiana is 13:1 to 1:5, the content of Cordyceps militaris is 1 to 1.3 billion spores / gram, the content of Beauveria bassiana is 1 to 500 million spores / gram, and the Cordyceps militaris is Cordyceps militaris JS001. The insecticidal composition is used to control the citrus inchworm.

2. The insecticidal composition according to claim 1, characterized in that: The spore concentration ratio of *Cordyceps militaris* to *Beauveria bassiana* was 7:

3.

3. The insecticidal composition according to claim 1, characterized in that: The insecticidal composition also includes adjuvants.

4. The insecticidal composition according to any one of claims 1-3, characterized in that: The insecticidal composition is in the form of a suspension.

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