Application of benzoate stored grain pest fumigant in prevention and control of stored grain pests

Abstract

The invention discloses an application of a benzoate stored grain pest fumigant in prevention and control of stored grain pests. Active ingredients in the stored grain pest fumigant are ethyl benzoate and / or propyl benzoate. It is found for the first time that ethyl benzoate and / or propyl benzoate are / is used as active substances of the fumigant, and effective prevention and control can be achieved on tribolium castaneum and callosobruchus maculatus. The benzoate stored-grain pest fumigant is used for preventing and controlling stored-grain pests, and is simple to operate, environment-friendly, efficient and wider in applicability.

Description

Technical Field

[0001] The present invention relates to the application of a benzoate fumigant for stored - grain pests in controlling storage pests, belonging to the field of pesticides. Background Art

[0002] Tribolium castaneum (Herbst), belonging to the family Tenebrionidae and the genus Tribolium, is distributed in most provinces and regions of China. It is an important storage pest, with a body color of bright red or dark red, concave dots on the elytra, an oblong - oval body shape, and a body length of 2 - 4 mm. Tribolium castaneum has a wide range of food habits and can damage various cereals and cash crops such as wheat, corn, and sorghum. In addition, the hydroxyquinone compound secreted by its stink glands can cause grain mildew, seriously affecting the quality of grains. Callosobruchus maculatus (Fabricius), belonging to the genus Callosobruchus, mainly damages the seeds of leguminous plants, including cowpeas, mung beans, broad beans, etc., and is the main pest during the storage of leguminous seeds. Its eggs are flat and oval; the last - instar larvae are light yellow - white and plump; the pupae are milky white or light yellow, oval, with fine hairs on the body surface; the adult body length is 2.5 - 4.0 mm, and the elytra are yellow - brown. Callosobruchus maculatus can cause serious infection and damage to leguminous seeds in a short time, resulting in a decrease in germination rate and loss of its market value.

[0003] Using chemical fumigants / insecticides is currently the most effective method for controlling storage pests. At present, the widely used insecticidal method is to use organophosphorus insecticides such as dichlorvos, etc. However, these toxic insecticides have caused great pollution to the environment. While killing pests, they also kill some beneficial insects, thus causing damage to the ecological environment. Pollution - free insecticides are the current research direction in the world. Now, the methods for killing pests without pollution include biological insecticides, light - induced insect killing, etc. These methods have not been widely used on a large scale due to high costs and limited types of pests that can be killed. For example, light - induced insect killing is currently only used at home to kill some mosquitoes and flies.

[0004] In the prior art, methyl bromide was widely used in the prevention and control of stored - grain pests worldwide in the 20th century due to its high - efficiency insecticidal effect. However, the Montreal Protocol in 1992 clearly pointed out that methyl bromide has a serious destructive effect on the ozone layer and was completely banned in 2015. Scientists from various countries are actively developing and searching for alternatives to methyl bromide. Currently, there are dozens of candidate fumigants under research, including phosphine, sulfuryl fluoride, methyl iodide, methyl formate, carbonyl sulfide, etc. However, these fumigants either have toxicity, resulting in toxic residues in commodities; or have poor effective penetration, and the fumigation effects on grain piles, wood, soil, etc. are not significant; or cannot pass registration due to economic, health and other reasons. With the gradual emergence of the drawbacks of chemical pesticides, natural plant pesticides have received increasing attention. Exploring and developing natural and highly efficient plant - derived insecticides is of great significance for the sustainable development of pest control.

[0005] Ethyl benzoate, with the molecular formula C9H 10 O2 and a relative molecular mass of 150.18, is a colorless transparent liquid with a fruity odor. It naturally exists in peaches, pineapples, and currants and can be used as an additive in food processing. The structural formula of ethyl benzoate is as follows:

[0006]

[0007] Propyl benzoate, with the molecular formula C 10 H 12 O2 and a relative molecular mass of 164.2, is a colorless oily liquid with a nutty and balsamic aroma. It naturally exists in sweet cherries and clove stems and can be used as a synthetic flavoring agent in food and also as a preservative in cosmetics. The structural formula of propyl benzoate is as follows:

[0008] Summary of the Invention

[0009] Object of the Invention: The object of the present invention is to provide the application of an environmentally friendly, effective, and non - resistant - generating benzoate - based stored - grain pest fumigant in the prevention and control of stored - grain pests.

[0010] Technical Solution: The present invention provides the application of a benzoate - based stored - grain pest fumigant in the prevention and control of stored - grain pests, and the active ingredient in the stored - grain pest fumigant is ethyl benzoate and / or propyl benzoate.

[0011] Benzoates are natural compounds produced by plants, which are not only more environmentally friendly but also have low toxicity to humans. Benzoates themselves have a fruity aroma and can increase the fragrance residue of grain fumigants. The present invention discovers that using the above two compounds as active ingredients can effectively control Tribolium castaneum and Callosobruchus maculatus. And because the above two compounds can be used as food additives in food processing, they will not have too much impact on grains and soybeans. Dissolving benzoates in acetone can increase the volatilization time of benzoates, thereby enhancing the fumigation effect. Benzoates may kill insects by interfering with their life activities such as respiration and digestion. Moreover, ethyl benzoate and propyl benzoate have no residues and are easily decomposed, which is an efficient and environmentally friendly method for controlling stored-grain pests.

[0012] Among them, the final concentration of ethyl benzoate is 0.08 - 4.94 g / L.

[0013] Among them, the final concentration of ethyl benzoate is 2.47 - 4.94 g / L.

[0014] Among them, the final concentration of propyl benzoate is 0.09 - 2.81 g / L.

[0015] Among them, the final concentration of propyl benzoate is 1.41 - 2.81 g / L.

[0016] Among them, the solvent in the stored-grain pest fumigant is acetone. [[ID=

[17] ]

[0017] Among them, the stored-grain pests are Tribolium castaneum and Callosobruchus maculatus.

[0018] Among them, the fumigation time is more than 48 hours, the fumigation temperature is 25 - 32 °C, and the fumigation humidity is 48 - 62%.

[0019] Among them, when the pest is Tribolium castaneum, the fumigation temperature is 29 - 31 °C, and the fumigation humidity is 48 - 52%.

[0020] Among them, when the pest is Callosobruchus maculatus, the fumigation temperature is 21 - 25 °C, and the fumigation humidity is 58 - 62%.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following prominent and significant advantages: The present invention discovers for the first time that using ethyl benzoate and / or propyl benzoate as the active substances of the fumigant can effectively control Tribolium castaneum and Callosobruchus maculatus. The benzoate-based stored-grain pest fumigant of the present invention is used for controlling stored-grain pests, with simple operation, environmental friendliness, high efficiency, and wider applicability. Description of the Drawings

[0022] Figure 1 Mortality rates of Tribolium castaneum larvae, pupae, and adults after being fumigated with ethyl benzoate in Example 3;

[0023] Figure 2 is the mortality rate of Callosobruchus maculatus larvae, pupae and adults after being fumigated with ethyl benzoate in Example 4;

[0024] Figure 3 is the mortality rate of Tribolium castaneum larvae, pupae and adults after being fumigated with propyl benzoate in Example 5;

[0025] Figure 4 is the mortality rate of Callosobruchus maculatus larvae, pupae and adults after being fumigated with propyl benzoate in Example 6. Detailed implementation manners

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0027] Example 1 Large-scale rearing of Tribolium castaneum

[0028] The tested Tribolium castaneum was reared in an artificial climate chamber using artificial feed (95% whole wheat flour, 5% yeast powder) at a temperature of 30 ± 1 °C, a relative humidity of 50 ± 2%, and a photoperiod of 0L:24D (0-hour light environment: 24-hour dark environment). Newly emerged adult Tribolium castaneum (3 days old) were allowed to lay eggs on the artificial feed for 24 hours, and then the eggs were separated using a 60-mesh steel sieve and transferred to fresh artificial feed for continued cultivation. Eggs (within 3 hours of oviposition), larvae (within 20 days of development from oviposition), pupae (within 12 hours of pupation), and adults (within 10 days of eclosion) of the new generation were used for the fumigation experiment with benzoate esters.

[0029] Example 2 Large-scale rearing of Callosobruchus maculatus

[0030] The insect population was fed with lentils and reared in 400 mL transparent plastic cups with small holes on the surface for air circulation. The rearing conditions were 27 °C, a relative humidity of 60%, and a photoperiod of 12L:12D. Since it mainly lives inside seeds, the lentils inoculated with test insects were checked daily, and then the development processes of larvae and pupae were tracked. The larvae of Callosobruchus maculatus were artificially divided into 4 instars based on the head capsule size. Eggs (within 3 days of oviposition), larvae (17 - 18 days of development from oviposition), pupae (within 24 hours of pupation), and adults (3 days after eclosion) of the new generation were used for the fumigation experiment with benzoate esters.

[0031] Example 3 Toxic effect of ethyl benzoate fumigant on Tribolium castaneum

[0032] Fifty larvae, pupae and adults of Tribolium castaneum were placed in each plastic petri dish (85 mm × 12 mm). Filter paper was pasted under the bottle cap, and ethyl benzoate (using acetone as the solvent) was added dropwise to the filter paper with a micro syringe (final concentrations were 0.08, 0.15, 1.24, 2.47, 4.94 g / L). The bottle cap was quickly covered and sealed with transparent tape. The control group (CK) was treated with pure acetone and sealed in the same way. The fumigation conditions were maintained at a temperature of 28 °C and a relative humidity of 48%. After 48 h of sealed fumigation, it was transferred to a ventilated place, and the lid of the narrow-mouth bottle was removed to completely remove the fumigant. Adults that showed no response to stimulation with a sterile needle were considered dead. The mortality rate after fumigation was counted, and the experiment was repeated at least 3 times. A bar chart was made based on the average mortality rate of each concentration. The results are as Figure 1 shown. The survival rate of Tribolium castaneum was logarithmically transformed, and probit analysis was performed using PoloPlus analysis software to calculate the median lethal concentration (Lethal Concentration50%, LC 50 ) and the 95% lethal concentration (Lethal Concentration 95%, LC 95 ) within the 95% confidence interval (95% Confidence Intervals, 95% CI).

[0033] Table 1. Fumigation toxicity of ethyl benzoate fumigant to Tribolium castaneum

[0034]

[0035] a. Number of experimental insects. b. Median lethal concentration. c. 95% lethal concentration. d. 95% confidence interval.

[0036] The results of the PoloPlus analysis are shown in Table 1. The median lethal concentrations LC 50 of larvae, pupae and adults were 0.81 g / L, 0.26 g / L and 0.50 g / L respectively, and the 95% lethal concentrations LC 95 were 13.98 g / L, 2.88 g / L and 5.92 g / L respectively. The chi-square values were 45.37, 16.44 and 50.65 respectively. It shows that the fumigant has a good killing effect on Tribolium castaneum, and the effect on pupae is the best.

[0037] Example 4 Toxic effect of ethyl benzoate fumigant on Callosobruchus maculatus

[0038] Place the cowpeas infected with 50 - 60 larvae, pupae and adults of Callosobruchus maculatus in plastic Petri dishes (85 mm × 12 mm). Paste filter paper under the bottle cap, and use a micro syringe to drop ethyl benzoate (using acetone as the solvent) onto the filter paper (the final concentrations are 0.08, 0.15, 1.24, 2.47 g / L respectively). Quickly cover the bottle cap and seal it with transparent tape. The control group (CK) drops pure acetone and makes the same sealing treatment. The fumigation conditions are maintained at 25 °C and a relative humidity of 58%. After 48 h of sealed fumigation, transfer it to a ventilated place and remove the lid of the narrow-necked bottle to completely disperse the fumigant. Adults that show no response to stimulation are considered dead. Count the mortality rate after fumigation. The experiment is repeated at least 3 times, and a bar chart is made based on the average mortality rate of each concentration. The results are as Figure 2 shown. The survival rates of the larvae, pupae and adults of Callosobruchus maculatus are logarithmically transformed, and probability analysis is performed using PoloPlus analysis software to calculate the median lethal concentration LC 50 at the 95% confidence interval and the 95% lethal concentration LC 95 .

[0039] Table 2. Fumigation toxicity of ethyl benzoate fumigant against Callosobruchus maculatus

[0040]

[0041] a. Number of experimental insects. b. 50% lethal concentration. c. 95% lethal concentration. d. 95% confidence interval.

[0042] The results of PoloPlus analysis are shown in Table 2. The median lethal concentrations LC 50 of ethyl benzoate against the larvae, pupae and adults of Callosobruchus maculatus are 0.31 g / L, 0.55 g / L and 0.32 g / L respectively, and the 95% lethal concentrations LC 95 are 1.80 g / L, 4.16 g / L, 1.87 g / L respectively. The chi-square values are 16.17, 18.83 and 17.84 respectively. It shows that this fumigant has a good killing effect on Callosobruchus maculatus. Comparing with the results of Example 3, Callosobruchus maculatus is more sensitive to this fumigant than Tribolium castaneum. Especially, the effects on the larvae and adults of Callosobruchus maculatus are the most obvious.

[0043] Example 5 Toxic effect of propyl benzoate fumigant on Tribolium castaneum

[0044] Fifty larvae, pupae and adults of Tribolium castaneum were placed in each plastic Petri dish (85 mm × 12 mm). Filter paper was pasted under the bottle cap, and propyl benzoate (using acetone as the solvent) was added dropwise to the filter paper with a micro syringe (final concentrations were 0.09, 0.18, 0.35, 0.70, 1.41, 2.81 g / L). The bottle cap was quickly covered and sealed with transparent tape. The control group was treated with pure acetone and sealed in the same way. The fumigation conditions were maintained at a temperature of 28 °C and a relative humidity of 48%. After 48 h of sealed fumigation, it was transferred to a ventilated place, and the lid of the narrow-mouth bottle was removed to completely remove the fumigant. Adults that showed no response to stimulation with a sterile needle were considered dead. The mortality rate after fumigation was counted. The experiment was repeated at least 3 times, and a bar chart was made based on the average mortality rate at each concentration. The results are as Figure 3 shown. The survival rate of Tribolium castaneum was logarithmically transformed, and probit analysis was performed using PoloPlus analysis software to calculate the median lethal concentration LC 50 at the 95% confidence interval and the 95% lethal concentration LC 95 .

[0045] Table 3. Fumigation toxicity of propyl benzoate fumigant against Tribolium castaneum

[0046]

[0047] a. Number of experimental insects. b. Median lethal concentration at 50%. c. Median lethal concentration at 95%. d. 95% confidence interval.

[0048] The results of the PoloPlus analysis are shown in Table 3. The median lethal concentrations LC 50 of Tribolium castaneum larvae, pupae and adults were 0.29 g / L, 0.16 g / L and 0.37 g / L respectively, and the 95% lethal concentrations LC 95 were 1.82 g / L, 1.87 g / L and 1.73 g / L respectively, and the chi-square values were 8.27, 7.60 and 11.97 respectively. It shows that the fumigant has a good killing effect on Tribolium castaneum, and the effect on pupae is the best.

[0049] Example 6 Toxic effect of propyl benzoate fumigant on Callosobruchus maculatus

[0050] The cowpeas infected with 50 - 60 larvae, pupae and adults of Callosobruchus maculatus were placed in plastic petri dishes (85mm×12mm). Filter paper was pasted under the bottle caps, and ethyl benzoate (using acetone as the solvent) was added dropwise to the filter paper with a micro syringe (final concentrations were 0.09, 0.18, 0.35, 0.70, 1.41 g / L respectively). The bottle caps were quickly covered and sealed with transparent tape. The control group was treated with pure acetone and sealed in the same way. The fumigation conditions were maintained at 25°C and 58% relative humidity. After 48 h of sealed fumigation, it was transferred to a ventilated place, and the lids of the narrow - necked bottles were removed to completely disperse the fumigant. The adults with no response to stimulation were considered dead. The mortality rate after fumigation was counted, and the experiment was repeated at least 3 times. Bar graphs were made based on the average mortality rate of each concentration. The results are as Figure 4 shown. The survival rate of Callosobruchus maculatus larvae was logarithmically transformed, and probit analysis was performed using PoloPlus analysis software to calculate the median lethal concentration LC 50 and the 95% lethal concentration LC 95 .

[0051] Table 4. Fumigation toxicity of propyl benzoate fumigant against Callosobruchus maculatus

[0052]

[0053] a. Number of experimental insects. b. 50% lethal concentration. c. 95% lethal concentration. d. 95% confidence interval.

[0054] The results of PoloPlus analysis are shown in Table 4. The median lethal concentrations LC 50 of propyl benzoate against Callosobruchus maculatus larvae, pupae and adults were 0.23 g / L, 0.27 g / L and 0.19 g / L respectively, and the 95% lethal concentrations LC 95 were 1.71 g / L, 1.08 g / L and 0.90 g / L respectively. The chi - square values were 17.12, 9.21 and 16.01 respectively. It shows that this fumigant has good killing effects on Callosobruchus maculatus larvae, pupae and adults. Compared with Tribolium castaneum, Callosobruchus maculatus is more sensitive to this fumigant, especially the adults show the most obvious effect.

Claims

1. Application of a benzoate grain pest fumigant in controlling storage pests, characterized in that, The active ingredients in the grain storage pest fumigant are ethyl benzoate and / or propyl benzoate.

2. Use of the benzoate grain pest fumigant according to claim 1 in controlling stored grain pests, characterized in that, The final concentration of the ethyl benzoate is 0.08 - 4.94 g / L.

3. Use of the benzoate grain pest fumigant according to claim 2 in controlling storage pests, characterized in that, The final concentration of the ethyl benzoate is 2.47 - 4.94 g / L.

4. Use of the benzoate grain pest fumigant according to claim 1 in controlling storage pests, characterized in that, The final concentration of the propyl benzoate is 0.09 - 2.81 g / L.

5. Use of the benzoate grain pest fumigant according to claim 4 in controlling storage pests, characterized in that, The final concentration of the propyl benzoate is 1.41 - 2.81 g / L.

6. Use of the benzoate grain pest fumigant according to claim 1 in controlling storage pests, characterized in that, The solvent in the grain storage pest fumigant is acetone.

7. Use of the benzoate grain pest fumigant according to claim 1 in controlling storage pests, characterized in that, The grain storage pests are Tribolium castaneum and Callosobruchus maculatus.

8. Use of the benzoate grain pest fumigant according to claim 1 in controlling stored grain pests, characterized in that, The fumigation time is more than 48 hours, the fumigation temperature is 25 - 32 °C, and the fumigation humidity is 48 - 62%.

9. Use of the benzoate grain pest fumigant according to claim 8 in the prevention and control of stored grain pests, characterized in that, When the pest is Tribolium castaneum, the fumigation temperature is 29 - 31 °C, and the fumigation humidity is 48 - 52%.

10. Use of the benzoate grain pest fumigant according to claim 8 in controlling storage pests, characterized in that, When the pest is Callosobruchus maculatus, the fumigation temperature is 21 - 25 °C, and the fumigation humidity is 58 - 62%.

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