Pesticide composition based on plasma activated water enhancement and application thereof

Abstract

The invention relates to a plasma activated water enhancement-based pesticide composition and application thereof, and aims to solve the technical problems of drug resistance crisis, environmental residue pollution and unstable control effect existing in chemical control of cotton aphids. Plasma activated water (PAW) and neonicotinoid / picolinamide insecticides are compounded to form a synergistic system with the concentration of LC10-LC75, oriented application is conducted on the basis of the insect age adaptation rule (imidacloprid is used for evaluation for 24 h, flonicamid is used for evaluation for young aphids, 72 h is used for evaluation for young aphids), the epidermis structure of cotton aphids is destroyed through reactive oxygen nitrogen substances (RONS) in the PAW, the permeability of the pesticides is enhanced, and therefore the cotton aphids with the concentration of LC10-LC75 are obtained. The comprehensive technical effects of remarkably improving the fatality rate of the cotton aphids at each age, reducing the pesticide dosage, reducing environmental residues and delaying the development of drug resistance are achieved.

Description

Technical Field

[0001] This invention relates to the field of crop pest and disease control technology, and in particular to a pesticide composition based on plasma-activated water enhancement and its application. Background Technology

[0002] Cotton is an important strategic resource and economic crop in my country, accounting for more than 13% of the global planting area, and its output has ranked first in the world for many consecutive years. Cotton aphids ( Aphis gossypii Glover As a major pest in cotton production, cotton aphids, both adults and nymphs, congregate on the tender leaves, stems, and boll buds of cotton plants, sucking sap and causing leaves to curl, become deformed, or even fall off. They also secrete honeydew, which induces sooty mold and severely hinders photosynthesis. Their damage directly leads to a 15%–30% reduction in cotton yield, a significant decline in fiber quality, and the transmission of various plant viruses, further exacerbating losses. Statistics show that cotton aphid outbreaks have occurred annually in all major cotton-growing areas of China, especially in Xinjiang (accounting for over 85% of the national cotton production), where the frequency of outbreaks has been increasing year by year due to suitable climatic conditions and growing pesticide resistance.

[0003] Currently, cotton aphid control technologies mainly include agricultural control, biological control and chemical control, but all of them have significant drawbacks: (1) Agricultural and physical control: such as crop rotation, yellow sticky traps, etc., are cumbersome to operate and have limited effect on large-scale field planting; (2) Biological control: relies on natural enemies such as ladybugs and lacewings, but the natural enemy population is limited by climate and habitat, the control speed is slow, and it is difficult to deal with outbreaks of pests; (3) Chemical control: has become the dominant means due to its high efficiency and convenience, but long-term reliance on a single type of pesticide has led to the development of pesticide resistance in pests, and the control efficiency has continued to decline; excessive application has led to the accumulation of environmental pollutants, threatening non-target organisms and human health.

[0004] In summary, there are three major gaps in existing technologies: ① lack of chemical alternatives that balance rapid lethality with protection of natural enemies; ② lack of low-cost, long-lasting aphid control methods suitable for field crops; ③ failure to solve the problem of synergistic optimization between pesticide reduction and resistance management.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The present application aims at the technical problems of high pesticide residue, intensified pesticide resistance and unstable control effect in the existing chemical control of cotton aphids, adopts the compounding of plasma-activated water (PAW) and neonicotinoid / pyridine amide insecticides, and based on the insect stage adaptation rule (adults use imidacloprid + 24h evaluation, and young aphids use flonicamid + 72h evaluation), the PAW is used for directional application, the active oxygen nitrogen substances (RONS) in the PAW are used for destroying the cuticle structure of cotton aphids and enhancing the penetration of pesticides, and the comprehensive technical effects of significantly improving the mortality of cotton aphids at different stages, reducing the pesticide dosage, reducing the environmental residue, and delaying the development of pesticide resistance are achieved.

[0007] According to one aspect of the present disclosure, an insecticide composition is provided, comprising: (a) an insecticidal active ingredient selected from at least one of a neonicotinoid insecticide and / or a pyridine amide insect growth regulator; (b) plasma-activated water (PAW) obtained by treating pure water with an atmospheric pressure plasma jet; The concentration of the insecticidal active ingredient in the composition is LC 10 ~ LC 75 .

[0008] In some embodiments of the present disclosure, the preparation method of the PAW comprises: The plasma jet nozzle is immersed in pure water, the distance between the nozzle tip and the water surface is 2-5 mm; air is used as the working gas, the gas flow rate is 10-20 L / min, the discharge power is 250-350 W, the treatment time is 15-25 min, and the water body is continuously stirred during the treatment.

[0009] In some embodiments of the present disclosure, the neonicotinoid insecticide is imidacloprid, thiamethoxam or acetamiprid, and the pyridine amide insect growth regulator is flonicamid.

[0010] In some embodiments of the present disclosure, the composition further comprises a pesticide adjuvant, the adjuvant comprises at least one of a surfactant, a dispersant or a stabilizer, and the total mass fraction of the adjuvant is 0.1%-5%.

[0011] According to another aspect of the present disclosure, the above-mentioned insecticide composition is applied in the control of cotton aphids.

[0012] In some embodiments of the present disclosure, the application of the above-mentioned insecticide composition comprises the following steps: (1) mixing the PAW with the insecticidal active ingredient to prepare a pesticide solution with a concentration of LC 10 ~ LC 75 ; (2) within 24h after mixing, spraying the pesticide solution on the parasitic sites of cotton aphids; (3) Selecting the insecticidal active ingredient according to the cotton aphid instar: For adults and fourth instar nymphs, imidacloprid is selected as the active ingredient, and the efficacy evaluation time is 24 hours after application; For first or second instar nymphs, flonicamid is selected as the active ingredient, and the efficacy evaluation time is 72 hours after application.

[0013] In some embodiments of the present disclosure, when the insecticidal active ingredient is imidacloprid, the field recommended concentration is 0.1-1 g / L.

[0014] The present application realizes a breakthrough improvement in the prevention and control technology of cotton aphids through the synergistic system of plasma-activated water and chemical pesticides, and the specific technical effects are as follows: 1. Drug resistance alleviating effect: experimental data show that at the LC 25 concentration, the lethality of the present application to imidacloprid-resistant populations (RR=86 times) is increased to 75.25% (adult stage), which is 38.50% higher than that of single-agent treatment, effectively breaking through the drug resistance barrier. By reducing the effective dose (40% less than the recommended dose), the adaptive evolution of cotton aphid metabolic enzyme system to the insecticidal component is delayed, and the development speed of field resistance is reduced by more than 70%.

[0015] 2. Environmental risk reduction: the synergistic system avoids or reduces the use of organic solvents, and the biodegradation rate of the preparation is improved. The actual amount of pesticide used is reduced to 20-50% of the conventional application, the soil residual amount is reduced to below the EU MRL standard (0.05 mg / kg), and the water ecological toxicity (LC 50 ) is increased to the safety threshold of bees (>0.1 μg / bee).

[0016] 3. Prevention and control efficiency improvement: ① Speed: the prevention and control efficiency on first instar nymphs is 78.33% 24 hours after application, which is 300% faster than that of single-agent treatment; the persistence period is extended to 14 days, which is 200% longer than that of conventional pesticides. ② Broad-spectrum: the comprehensive prevention and control efficiency on cotton aphids of all ages (from first instar to adult) is 68.9%, which solves the technical defect that physical control is ineffective on nymphs.

[0017] 4. Mechanism innovation: building a "physical damage-biochemical inhibition" dual-killing mode: scanning electron microscopy confirms that the epidermal structure damage rate is 100%, which is 45% higher than that of single-agent treatment; the metabolic enzyme activity inhibition rate is increased to 83%, which blocks the oxidative stress balance. The antifeeding effect appears 2 hours after treatment, which is 12 hours faster than that of flonicamid single-agent, forming a complex effect of rapid killing and growth inhibition. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1The synergistic effect diagram of PAW combined with imidacloprid on the insecticidal activity of different instar field strains of cotton aphids in the embodiments of the present application; wherein (a) is the effect on the mortality of first instar (N1) cotton aphids, (b) is the effect on the mortality of second instar (N2) cotton aphids, (c) is the effect on the mortality of third instar (N3) cotton aphids, (d) is the effect on the mortality of fourth instar (N4) cotton aphids, and (e) is the effect on the mortality of adults (Adult).

[0019] Figure 2 The synergistic effect diagram of PAW combined with flonicamid on the insecticidal activity of different instar field strains of cotton aphids in the embodiments of the present application; wherein (a) is the effect on the mortality of first instar (N1) cotton aphids, (b) is the effect on the mortality of second instar (N2) cotton aphids, (c) is the effect on the mortality of third instar (N3) cotton aphids, (d) is the effect on the mortality of fourth instar (N4) cotton aphids, and (e) is the effect on the mortality of adults (Adult).

[0020] Figure 3 The electron microscope photos of the surface morphology of cotton aphids treated with PAW combined with imidacloprid or flonicamid in the embodiments of the present application. DETAILED DESCRIPTION

[0021] In order to better understand the technical solutions of the present application, the above technical solutions will be described in detail below in combination with the drawings of the specification and specific embodiments.

[0022] The main materials used in the following embodiments are as follows: 1. Preparation of plasma-activated water (PAW) ① Device configuration: an atmospheric pressure plasma jet (APPJ) device was used, and compressed air (purity ≥ 99.9 %) was used as the working gas; the inner diameter of the copper nozzle was 2.0 mm, and it was vertically fixed at the liquid treatment position.

[0023] ② Process parameters: 500 mL of deionized water was injected into a glass reactor (diameter 15 cm, height 20 cm); the distance between the nozzle tip and the liquid surface was adjusted to 3.0 ± 0.1 mm; the gas flow rate was 15.0 ± 0.5 L / min, the discharge power was 300 ± 5 W, and the treatment time was 20.0 ± 0.5 min; ③ Activity maintenance: the pH value of the obtained PAW was reduced to 2.8 ~ 3.2, and the oxidation-reduction potential (ORP) reached +1100 to +1150 mV; it was stored in a 4 ℃ light-proof environment, and the half-life of the active ingredients was ≤ 24 h, and it was prepared and used immediately.

[0024] 2. Preparation of test insects: Field resistant strain of cotton aphids were collected and continuously propagated on cotton seedlings in a greenhouse for 3 generations; the aphids were grouped according to their age: 1st instar nymphs (24 h after hatching), 2nd instar nymphs (48 h), 3rd instar nymphs (72 h), 4th instar nymphs (96 h), and adults (5 d after eclosion).

[0025] 3. Source of reagents 98% imidacloprid technical material, 95% flonicamid technical material (Dow AgroSciences, USA); 10% imidacloprid wettable powder (Jiangsu Lanfeng Biological Chemical Co., Ltd.).

[0026] Example 1: Synergistic effect of PAW with imidacloprid and flonicamid on cotton aphids 1. Preparation of pesticide solutions: First, imidacloprid and flonicamid technical materials were each prepared into a higher concentration stock solution of 10,000 ug / mL and 20,000 ug / mL using an acetone solution.

[0027] Control group: H2O, PAW, H2O + imidacloprid / H2O + flonicamid (LC 25 Concentration, field strain imidacloprid synergism experiment: 1st to 4th instar nymphs were treated with 1 ug / mL imidacloprid solution, i.e., 10 ul of imidacloprid stock solution was added to H2O to prepare 100 ml of H2O + imidacloprid; adults were treated with 2 ug / mL imidacloprid solution, i.e., 20 ul of imidacloprid stock solution was added to H2O to prepare 100 ml of H2O + imidacloprid. Field strain flonicamid synergism experiment: 1st to 4th instar nymphs were treated with 1 ug / mL flonicamid solution, i.e., 5 ul of flonicamid stock solution was added to H2O to prepare 100 ml of H2O + flonicamid; adults were treated with 2 ug / mL flonicamid solution, i.e., 10 ul of flonicamid stock solution was added to H2O to prepare 100 ml of H2O + flonicamid).

[0028] Test group: The prepared plasma-activated water was immediately used as a carrier solvent to prepare LC 25Concentration (field strain imidacloprid synergistic experiment: 1st to 4th instar nymphs used 1 ug / mL imidacloprid solution, i.e. 10 ul imidacloprid stock solution was added to PAW to configure 100 ml PAW + imidacloprid; adults used 2 ug / mL imidacloprid solution, i.e. 20 ul imidacloprid stock solution was added to PAW to configure 100 ml PAW + imidacloprid. Field strain flonicamid synergistic experiment: 1st to 4th instar nymphs used 1 ug / mL flonicamid solution, i.e. 5 ul flonicamid stock solution was added to PAW to configure 100 ml PAW + flonicamid; adults used 2 ug / mL flonicamid solution, i.e. 10 ul flonicamid stock solution was added to PAW to configure 100 ml PAW + flonicamid) imidacloprid and flonicamid solution.

[0029] 2. Application and evaluation: 30 heads of the same age period of cotton aphids were applied to each cotton seedling (3 leaf stage); the liquid of different treatments was uniformly sprayed on the surface of the corresponding insect-infested cotton leaves, so that the cotton and the cotton aphids on the cotton were in full contact with the liquid. Environmental control: temperature 25 ± 1℃, humidity 65 ± 5%, photoperiod L:D = 16:8. Starting 24 h after treatment, the number of dead insects under each treatment was checked and counted every day (insects with rigid body and no response were determined as dead), and the results are shown in Figure 1 、 Figure 2

[0030] As shown in Figure 1 , compared with pure water spraying, plasma-activated water had a slight killing effect on cotton aphids to some extent. When plasma-activated water was used as a solvent to prepare LC 25 concentration imidacloprid, the mortality of cotton aphids was greatly improved, with 1st instar nymph mortality increasing from 44.06% to 77.25%, 2nd instar nymph mortality increasing from 40.23% to 58.83%, 3rd instar nymph mortality increasing from 40.65% to 55.79%, 4th instar nymph mortality increasing from 33.19% to 58.36%, and adult mortality increasing from 36.75% to 75.25%. The results show that plasma-activated water has a significant synergistic effect on cotton aphids of different instar nymphs in the field strain when combined with imidacloprid ( P <0.05), and the effect is best in the adult stage of cotton aphids, with a mortality increase of 38.50%.

[0031] As shown in Figure 2 , LC 25 ​The synergistic effect of PAW on the mortality of cotton aphids was observed by using flonicamid at different concentrations. The results showed that for the third instar, fourth instar nymphs and adults, PAW could improve the mortality of cotton aphids, but there was no significant difference among the treatment groups (P>0.05). However, for the first and second instar nymphs, PAW as a solvent could significantly increase the biological activity of flonicamid on cotton aphids (P<0.05), and the mortality rate increased from 46.67% and 42.62% to 78.33% and 85.91%, respectively.

[0032] 3. Electron microscope observation: Field emission scanning electron microscope (FE-SEM, Hitachi SU8010) was used to observe and analyze the epidermal structure of cotton aphids after treatment (accelerating voltage 5.0 kV). The results showed that (Fig. 3) Figure 3 ), the epidermal pattern of water-treated cotton aphids was relatively complete, while PAW caused epidermal shrinkage. Compared with pure imidacloprid or flonicamid treatment, the epidermal pattern of cotton aphids was completely destroyed after PAW combined with pesticide (imidacloprid or flonicamid) treatment. Both pesticides (imidacloprid or flonicamid) and PAW could damage the surface morphological structure of cotton aphids, and the damage was more obvious after PAW combined with pesticides (imidacloprid or flonicamid). Therefore, it can be seen that PAW combined with pesticides has a multi-target mechanism: PAW enhances the permeability of pesticides by destroying the epidermal structure of cotton aphids, forming a double-killing mechanism with the neurotoxicity of pesticides; the RONS component can interfere with the metabolic enzyme balance of cotton aphids, and produce synergistic toxicity with the antifeeding effect of pesticides.

[0033] Example 2: Verification of control effect under actual concentration in the field 1. Preparation of drug: The required drugs for each treatment were prepared according to Table 1.

[0034] Table 1 Test treatments and drugs .

[0035] 2. Application and evaluation: Different instar cotton aphids were inoculated on corresponding fresh cotton seedlings, 30 per seedling, to form different pest stages; at the same time, the drug solution of different treatments (see Table 1) was uniformly sprayed on the surface of the corresponding cotton leaves, so that the cotton and cotton aphids on the cotton could fully contact with the drug solution. Environmental control: temperature 25±1℃, humidity 65±5%, light cycle L:D=16:8. The dead insect number was checked and counted every day after treatment for 24 hours (insect body rigid without response was determined as dead), and the results are shown in Table 2.

[0036] Table 2 Number of insects treated with four kinds of drugs (heads) .

[0037] As can be seen from Table 2, PAW as a pesticide adjuvant, at the recommended concentration in the field, achieved multiple breakthroughs in the control effect of imidacloprid: ① Rapidly effective: within 24 hours of application, the insect population was reduced by 2.7 times (treatment III: 47.80 vs treatment II: 114.00); ② Strong persistence: 5 days after application, the insect population was stably controlled at 12.20 ± 1.48, which was 76.3% lower than the residual amount of conventional imidacloprid treatment (51.40 ± 4.98); ③ Inhibition of efficacy decline: the insect population rebound rate of treatment III was 0% (5 days after treatment vs 3 days after treatment: 12.20 vs 12.80), while the rebound rate of treatment II was 104.5% (51.40 vs 49.20); ④ Stability of control effect: the standard deviation of treatment III group (1.48 ~ 7.46) was significantly lower than that of treatment II (4.98 ~ 7.11), indicating that PAW adjuvant improves the consistency of control.

[0038] There was no significant difference (P > 0.05) between the insect population change of PAW alone treatment (group I) and the blank group (CK), which proved that PAW itself had no insecticidal activity, and the synergistic effect was completely due to synergistic effect; the natural growth rate of the insect population in the blank control group (CK) was 130.0% (198.40→456.20), highlighting the severe pest pressure during the test period, further supporting the excellent control effect of treatment III.

[0039] Therefore, when PAW is used as an adjuvant for imidacloprid at a field concentration of 0.5 g / L, it can achieve a ≥ 75% reduction in insect population within 24 hours, and the control effect is stably maintained at more than 93% after 5 days, which is 20.15 percentage points higher than conventional chemical control. This scheme simultaneously solves the two technical bottlenecks of insufficient rapid effect and persistence decline, and provides data support for pesticide reduction (reducing the amount of chemical pesticides by 20% ~ 50%), and reducing the risk of environmental residues.

[0040] Although some preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they understand the basic inventive concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0041] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the inventive concept. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application also intends to include these modifications and variations.

Claims

1. A pesticide composition, characterized in that, Include: (a) an insecticidal active ingredient selected from at least one of neonicotinoid insecticides and / or pyridine amide insect growth regulators; (b) Plasma-activated water, which is obtained by treating pure water with atmospheric pressure plasma jets; The concentration of the insecticidal active ingredient in the composition is LC. 10 ~ LC 75 .

2. The pesticide composition according to claim 1, characterized in that, The method for preparing the plasma-activated water includes: Immerse the plasma jet nozzle in pure water, with the nozzle tip 2-5 mm above the liquid surface; use air as the working gas, with a flow rate of 10-20 L / min, a discharge power of 250-350 W, and a treatment time of 15-25 min, while continuously stirring the water during the treatment process.

3. The pesticide composition according to claim 1 or 2, characterized in that, The neonicotinoid insecticide is imidacloprid, thiamethoxam, or acetamiprid, and the pyridine amide insect growth regulator is flonicamid.

4. The pesticide composition according to claim 1 or 2, characterized in that, The composition also contains pesticide adjuvants, which include at least one of surfactants, dispersants, or stabilizers, and the total mass percentage of the adjuvants is 0.1% to 5%.

5. The application of the pesticide composition of claim 1 in the control of cotton aphids.

6. The application according to claim 5, characterized in that, Includes the following steps: (1) Mix plasma-activated water with insecticidal active ingredients to prepare a solution with a concentration of LC. 10 ~ LC 75 The medicinal liquid; (2) Spray the solution onto the cotton aphid-infested areas within 24 hours after mixing; (3) Select insecticidal active ingredients according to the age of cotton aphids: For adult aphids and fourth instar nymphs, imidacloprid was selected as the active ingredient, and the efficacy evaluation time was 24 hours after application. For first- or second-instar nymphs, flonicamid was selected as the active ingredient, and the efficacy was evaluated 72 hours after application.

7. The application according to claim 5, characterized in that, When the insecticidal active ingredient is imidacloprid, the recommended field concentration is 0.1~1 g / L.

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