Snail-killing pesticide and application thereof

Abstract

The application discloses a kind of snail pesticides and its application, belong to biological control technical field.Sodium dodecyl sulfate (SDS) and tetra acetal are compounded to obtain snail pesticide compound agent according to mass concentration ratio, wherein the mass concentration of SDS is 4%-6%, the mass concentration of tetra acetal is 2%, preferably the concentration of SDS is 5%, and then the pesticide is applied by dripping.The mortality of the compound agent to gray field slug reaches 100% within 64 h, and the dosage is greatly reduced compared with single agent.The application solves the problems of poor water solubility and unstable effect of traditional tetra acetal preparation, overcomes the antagonistic effect of surfactant compound, provides an efficient technical solution for snail green control, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of biological control technology, specifically relating to a snail-killing pesticide and its application. Background Technology

[0002] Snails are significant pests in agricultural production, with their wide-ranging diet, strong concealment, and high reproductive capacity causing serious damage to vegetables, field crops, and garden plants. The gray barnacle snail and the homotypic barnacle snail, common snail species in my country, not only directly harm crops leading to yield reduction but also spread plant pathogens and parasites (such as schistosomes and angiostrongylus cantonensis), posing a potential threat to public health. Currently, snail control mainly relies on chemical agents (such as metaldehyde), but long-term use can easily lead to problems such as drug resistance, environmental pollution, and non-target organism toxicity. While physical control (such as manual removal) and biological control (such as the introduction of natural enemies) have some effect, their implementation costs are high or their effects are slow, making them difficult to meet the needs of large-scale farmland control.

[0003] Metaldehyde is currently the dominant pesticide for snail control, exerting its toxic effect by disrupting the snail's acetylcholinesterase system. However, metaldehyde is easily decomposed in acidic environments, and low concentrations are ineffective against snails. While high concentrations do have some effect, long-term use may lead to snail resistance. Furthermore, chemical pesticides generally suffer from low utilization rates (approximately 40%), and high concentrations can leave residues and pollution, negatively impacting non-target aquatic organisms and the ecological environment.

[0004] To improve pesticide utilization and reduce the amount of chemical pesticides used, pesticide synergists have become a research hotspot. Synergists can significantly enhance pesticide efficacy by improving the wettability and penetration of pesticide solutions or delaying pesticide decomposition. Surfactants, as common synergists, can reduce the surface tension of pesticide solutions and improve adhesion, but their application in snail control has not been extensively explored. Therefore, there is an urgent need to explore new low-cost, low-concentration, high-efficiency, and environmentally friendly snail control pesticides. Summary of the Invention

[0005] In view of this, one of the objectives of the present invention is to provide a snail-killing pesticide composition comprising sodium dodecyl sulfate and metaldehyde, wherein the mass ratio of sodium dodecyl sulfate to metaldehyde is 2-3:1.

[0006] Preferably, the mass ratio of sodium dodecyl sulfate to metaldehyde is 2.5:1.

[0007] The second objective of this invention is to provide a snail-killing pesticide comprising sodium dodecyl sulfate and metaldehyde, with the addition of a pharmaceutically acceptable carrier and / or excipient, wherein the mass concentration of sodium dodecyl sulfate is 4%-6% and the mass concentration of metaldehyde is 2%.

[0008] The pharmaceutically acceptable carrier and / or excipient is water.

[0009] Preferably, the sodium dodecyl sulfate has a mass concentration of 5% and the metaldehyde has a mass concentration of 2%.

[0010] The third objective of this invention is to provide a method for killing snails, which involves diluting the pesticide composition described above to a mass concentration of 4%-6% for sodium dodecyl sulfate and 2% for metaldehyde, or directly applying the pesticide to the junction of the snail shell and soft tissue using a drip method.

[0011] The dilution is achieved by diluting with water.

[0012] The junction between the snail shell and the soft tissue is near the foot of the snail's mouth.

[0013] Preferably, the pesticide composition described above is diluted to a concentration of 5% by mass of sodium dodecyl sulfate and 2% by mass of metaldehyde.

[0014] Furthermore, the dosage of the drug was 50 µL per snail.

[0015] The fourth objective of this invention is to provide the application of the pesticide composition described above or the pesticide described above in the control of snails.

[0016] Furthermore, the snail is a gray snail.

[0017] The fifth objective of this invention is to provide the application of the above-described method in the control of snails.

[0018] This invention combines the anionic surfactant sodium dodecyl sulfate (SDS) and metaldehyde. The resulting solution showed a 100% lethal effect on the gray snail after 64 hours, demonstrating a significant synergistic effect. In contrast, combining SDS with metaldehyde, another anionic surfactant, only resulted in an additive effect. Therefore, the combination of SDS and metaldehyde of this invention is effective in controlling the gray snail. The concentration of SDS can be any of 4%, 5%, or 6%, and the concentration of metaldehyde is 2%. The best results are achieved with a combined solution containing 5% SDS and 2% metaldehyde. Attached Figure Description

[0019] Figure 1 Comparison of mortality rates between the drip application method and the spray application method of this invention (left: mean, right: standard deviation);

[0020] Figure 2The two anionic surfactants of this invention are shown to control gray snails. SDS is on the left and sodium dodecyl sulfate is on the right.

[0021] Figure 3 The efficacy of different concentrations of metaldehyde single agent of the present invention against gray snails;

[0022] Figure 4 The present invention describes the effects of different compound ratios of SDS and metaldehyde on the control of gray snails. Detailed Implementation

[0023] The present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of application of the present invention. The present invention is not limited to the following embodiments or examples. Any modifications and variations made without departing from the spirit of the present invention should be included within the scope of the present invention. Unless otherwise specified, the experimental materials or reagents used in the following embodiments are commercially available.

[0024] Example 1: Effects of spraying and dripping methods on the mortality rate of gray snails

[0025] This invention first conducted a preliminary experiment on the effect of different application methods on the mortality rate of gray snails, comparing the effects of spraying and dripping methods on the mortality rate of gray snails. The results are as follows: Figure 1 As shown, the mortality rate of the drip method for gray snails is close to 70%, while the mortality rate of the spray method is about 40%. The drip method is more effective than the spray method in reducing the mortality rate of gray snails, so the drip method was used for subsequent experiments.

[0026] Example 2: Snail-killing activity of surfactants such as SDS

[0027] Preparation of solutions with different concentration gradients:

[0028] The experiment included a control group and treatment groups. The control group consisted of water, while the treatment groups consisted of SDS solution and sodium dodecyl sulfate solution. Water was used as the solvent in each treatment group, and the concentrations (mass concentrations) were 5%, 10%, 15%, 20%, and 25%. The anionic surfactants, SDS (sodium dodecyl sulfate) and sodium dodecyl sulfate, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (item number: S639075).

[0029] Grey snail treatment:

[0030] Test insects: Purchased from Wotian Family Farm in Sixian County. Fifty Bradybaena ravida snails (shell width 23.1±1.8mm, weight 1.45±0.33g) that were climbing the wall, appeared normal and were very active were introduced into each group in a clean polyethylene transparent box.

[0031] Drug application: Apply 50 µL of liquid to the junction of the soft tissue and shell of the tested gray snail (near the foot of the snail mouth) using a pipette.

[0032] Observation: Fresh lettuce was added to each box for feeding. The test insects, after being treated with drip irrigation, were placed in a laboratory at a temperature of 26 ℃, a light cycle (L:D) of 16:8, and a relative humidity of 70%. Snail mortality was observed every 8 hours, and dead snails were removed and the number of deaths was recorded. Then, the snails were left to rest in the insect rearing environment for a total of 72 hours.

[0033] Methods for determining death: Observe the body for dull coloration, no head extension response after immersion in water, and stimulate the soft tissue with a needle; if the body does not retract voluntarily, it is considered dead.

[0034] Methods for calculating survival and mortality rates:

[0035] Snail survival rate (%) = [Number of surviving snails after application / Total number of snails before application] × 100%;

[0036] Corrected survival rate (%) = [(Survival rate of treatment group - Survival rate of control group) / (1 - Survival rate of control group) × 100%;

[0037] (If the survival rate of the control area is 100%, then the denominator "(1 - survival rate of the control area)" is considered as 1);

[0038] Mortality rate (%) = 1 - corrected survival rate.

[0039] Each experiment was conducted with three biological replicates, three different experiments, for a total of nine experiments, to ensure the stability of the experimental results.

[0040] result:

[0041] Depend on Figure 2 As shown, the mortality rate of SDS on snails tends to increase with increasing concentration. When the SDS concentration is 5%, the mortality rate of gray snails after 72 hours of treatment is only about 30%. The lethal effect of sodium dodecyl sulfate on snails also increases with increasing concentration. Overall, SDS is superior to sodium dodecyl sulfate.

[0042] Example 3: Synergistic effect of SDS and metaldehyde

[0043] Preparation of compound solution:

[0044] Method for preparing a compound solution of SDS and metaldehyde (Aladdin, item number: M110038) in a 5:2 ratio: Dissolve the surfactant SDS in water to prepare a 10% mass concentration solution; dissolve the metaldehyde in water to prepare a 4% mass concentration solution; then mix the prepared surfactant solution and the metaldehyde solution in equal volumes to prepare a compound solution of 5% SDS and 2% metaldehyde.

[0045] Using the same method, prepare compound solutions of SDS and metaldehyde in ratios of 2:2, 3:2, 4:2, 6:2, and 7:2.

[0046] Sodium dodecyl sulfonate, which is also an anionic surfactant, was prepared into a 5% sodium dodecyl sulfonate and 2% metaldehyde compound solution according to the above method.

[0047] Group A: SDS + metaldehyde

[0048] Group B: Sodium dodecyl sulfonate + metaldehyde

[0049] Control group: metaldehyde single agent

[0050] The treatment method for gray snails was the same as that for gray snails in Example 1. Three biological replicates were set up for each experiment, and three different experiments were conducted, for a total of nine experiments, to ensure the stability of the experimental results.

[0051] Calculation Methods: In bioassays designed to assess interactions between different surfactant treatments and the chemical pesticide metaldehyde, or interactions between different surfactants, data from mixtures were evaluated using an independent-action model. The binomial test described by Nishimatsu and Jackson was used to determine whether these interactions were additive, synergistic, or antagonistic, comparing the expected and observed percentages of mortality. This model quantifies the probability of survival when two pressures act independently on the same organism. While it has not been effectively applied to describe mixtures of surfactants and pesticides in previous studies, it has been reported to be used to calculate synergistic effects of chemical agents and pesticides. A chi-square test was used to analyze the type of interaction between the surfactant and metaldehyde. Data were initially corrected for controls and then converted to proportions (i.e., from 0-100% to 0-1). The expected mortality rate without interaction (additive effect) was calculated as follows:

[0052] Me = Ma + Mb × (1 - Ma)

[0053] χ²=[(Mab-Me)×100]×[(Mab-Me)×100] / (Me×100)

[0054] In this study, Me represents the expected mortality rate of additive mortality, while Ma, Mb, and Mab represent the observed mortality rates of treatments with surfactant, chemical pesticide, and their combination, respectively. The P-value was determined using a chi-square table with the degrees of freedom (df) equal to 1. If χ² < 3.84, it indicates an additive effect. If χ² > 3.84 and Mab < Me, it indicates an antagonistic effect; if χ² > 3.84 and Mab > Me, it indicates a synergistic effect.

[0055] The control results of metaldehyde single agent at different concentrations against Bradybaena ravida are as Figure 3 shown. When the metaldehyde concentration is 2%, the lethality rate against Bradybaena ravida is about 10%.

[0056] In the synergistic analysis, the mortality rates of some treatment groups reached or approached 100%. Considering that there may be a ceiling effect in the high-mortality range and some treatment groups (94% and 100%) have tended to saturate in biological effects, this study selected the treatment groups with a mortality rate of 100% as the calculation basis for the chi-square test. This selection avoided potential overestimation of the synergistic effect and made the determination of synergism more conservative and robust. At the same time, the synergistic experiment does not simply compare the difference significance of mortality data between different groups, but compares the difference between the expected value fitted by the formula and the actually observed mortality rate. Therefore, the average value is not used in this experiment for calculation. The synergistic experiment results of the compounding of two anionic surfactants and metaldehyde (5:2) are shown in Table 1. The compounding of 5% SDS + 2% metaldehyde shows a synergistic effect, while the compounding of 5% sodium dodecyl sulfonate and 2% metaldehyde shows only an additive effect.

[0057] Table 1 Effects of the compounding of anionic surfactants and metaldehyde on controlling Bradybaena ravida

[0058]

[0059] Meanwhile, the present invention also conducted control experiments on the compounding solutions of SDS and metaldehyde in the ratio groups of 2:2, 3:2, 4:2, 5:2, 6:2, and 7:2 against Bradybaena ravida. The experiments were repeated three times and all showed a synergistic effect. In addition, from Figure 4It was observed that at the 8th hour, the 5:2 and 7:2 ratio solutions were more effective than the other groups; at the 16th hour, the 5:2 group remained the most effective, while the lethal effect of the 7:2 ratio on gray snails began to slow down, but it was still better than the other four groups; from the 24th hour onwards, the 4:2, 5:2, and 6:2 ratios showed better lethality rates on gray snails than the other groups, and at this point, except for the 7:2 group, the lethality rates of the other groups continued to rise rapidly; at the 32nd hour, the 7:2 ratio... The group with the lowest mortality rate was the 5:2 ratio of SDS to metaldehyde, which was significantly lower than the 2:2 ratio. At 64 hours, the control effect peaked when the SDS:2 to metaldehyde ratio was 5:2. The 4:2 and 6:2 ratios were slightly less effective than 5:2, but still relatively good. However, at this point, the 7:2 ratio was significantly less effective against gray snails than the 4:2, 5:2, and 6:2 ratios, with a mortality rate of less than 60%. It wasn't until 80 hours that the mortality rate of the 7:2 ratio slightly exceeded 60%. Therefore, when the ratio of SDS to metaldehyde was less than 5:2, the control effect against gray snails increased with increasing concentration, peaking at 5:2. At 6:2, the effect slightly decreased. The 4:2, 5:2, and 6:2 ratios all showed excellent control effects against gray snails, but the effect significantly decreased at a 7:2 ratio. Therefore, the combination of SDS and metaldehyde (4%-6%) at a ratio of 2% has a significant control effect on gray snails, with the 5:2 ratio showing the best effect.

[0060] Therefore, the results above show that SDS and metaldehyde have a significant synergistic effect when combined, and the mortality rate of gray snails can reach 100% when 5% SDS and 2% metaldehyde are combined and dripped at 64h; while 5% sodium dodecyl sulfonate and 2% metaldehyde, which are both anionic surfactants, only have an additive effect when combined.

[0061] In summary, low concentrations of the anionic surfactants SDS or metaldehyde have only a very low impact on snail survival rates. Specifically, 5% SDS showed a mortality rate of only about 15% after 72 hours, and 2% metaldehyde showed a mortality rate of only about 10% after 72 hours. However, the combined solution of 5% SDS and 2% metaldehyde achieved a 100% mortality rate after 64 hours, demonstrating a significant synergistic effect. Combining sodium dodecyl sulfate, also an anionic surfactant, with metaldehyde only showed an additive effect. Furthermore, regarding the control efficacy of different concentrations of SDS and metaldehyde in snail control, although SDS showed an increasing efficacy against gray snails with increasing concentration, the combined effect of SDS and metaldehyde only increased within a certain concentration range and then decreased. The combination of SDS and metaldehyde at a concentration ratio of (4%-6%):2% shows significant control efficacy and can be used as a pesticide formulation for controlling gray snails. A further optimal formulation of SDS to metaldehyde is 5%:2%. Therefore, the snail-killing pesticide described in this invention has broad application prospects in the control of gray snails.

[0062] The conventional techniques and solutions not described in detail in the above embodiments are all well known in the art, and therefore will not be elaborated upon here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A snail-killing pesticide composition, characterized in that, It contains sodium dodecyl sulfate and metaldehyde, wherein the mass ratio of sodium dodecyl sulfate to metaldehyde is 2-3:

1.

2. The pesticide composition according to claim 1, characterized in that, The mass ratio of sodium dodecyl sulfate to metaldehyde is 2.5:

1.

3. A snail-killing pesticide, characterized in that, It contains sodium dodecyl sulfate and metaldehyde, wherein the mass concentration of sodium dodecyl sulfate is 4%-6% and the mass concentration of metaldehyde is 2%.

4. The pesticide as described in claim 3, characterized in that, The sodium dodecyl sulfate has a mass concentration of 5%, and the metaldehyde has a mass concentration of 2%.

5. A method for killing snails, characterized in that, The pesticide composition of claim 1 is diluted to a mass concentration of 4%-6% for sodium dodecyl sulfate and 2% for metaldehyde, or the pesticide of claim 3 or 4 is directly applied by drip application to the junction of the snail shell and soft tissue.

6. The method as described in claim 5, characterized in that, The pesticide composition of claim 1 is diluted to a mass concentration of 5% for sodium dodecyl sulfate and 2% for metaldehyde.

7. The method as described in claim 5 or 6, characterized in that, The dosage for each snail is 50 µL.

8. The application of the pesticide composition of claim 1 or the pesticide of claim 3 in the control of snails.

9. The application as described in claim 8, characterized in that, The snail in question is the gray snail.

10. The application of the method of claim 5 in the control of snails.

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