Application of pirolocarb and tremorin M as insecticide synergist

Abstract

The invention discloses an application of pirolocarb and tremorin M as a pesticide synergist. Experiments for measuring the toxicity of bactrocera dorsalis adults show that the synergistic ratio of pirolocarb to fipronil is 2.58, and the synergistic ratio of pirolocarb to acetoprole is 1.30; the synergistic ratio of the oxidized tremor M to the fipronil is 2.03, and the synergistic ratio of the oxidized tremor M to the acetoprole is 1.87; it is proved that the pirolocarb and the oxic tremor M have the insecticidal synergistic effect on insecticides fipronil and acetoprole and can be used as insecticide synergists for preventing and controlling bactrocera dorsalis.

Description

Technical Field

[0001] The present invention belongs to the technical field of insecticides, and particularly relates to the application of pilocarpine and oxotremorine M as insecticide synergists. Background Art

[0002] The oriental fruit fly, Bactrocera dorsalis (Hendel), also known as the citrus fruit fly, orange fruit fly, and oriental fruit fly, belongs to the family Tephritidae of the order Diptera and is one of the most destructive and invasive polyphagous pests in global agriculture. This insect is characterized by a wide distribution range, strong reproductive ability, complex feeding habits, short developmental duration, severe generation overlap, strong environmental adaptability, and a high risk of outbreak. It mainly damages more than 250 fruits, vegetables, and flowers in 46 families such as guava and mango. In the past two decades of observation and research, it has been found that the areas where this insect is distributed are gradually spreading to the northern high-latitude regions, posing a greater challenge to its integrated prevention and control.

[0003] Currently, the most common method for controlling the oriental fruit fly is still the use of chemical insecticides, which has led to very serious insecticide resistance in the oriental fruit fly. In addition, due to problems such as environmental pollution caused by excessive pesticide application and the pressure of pesticide application costs, many pesticides have been banned, posing a more severe test for the prevention and control of the oriental fruit fly. By using pesticide synergists to improve the insecticidal efficiency of developed insecticides, the content of active ingredients required in pesticide formulations can be reduced, the harmful toxicity to beneficial arthropods, mammals, and the environment can be reduced, and at the same time, the problem of insecticide resistance in pests can be effectively alleviated. Therefore, exploring new types of synergists is beneficial for the prevention and control of pests, especially the oriental fruit fly. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the present invention provides the application of pilocarpine and oxotremorine M as insecticide synergists.

[0005] The first object of the present invention is to provide the application of pilocarpine as an insecticide synergist.

[0006] Preferably, the insecticide is fipronil or acetoprole.

[0007] Preferably, the insecticide is fipronil.

[0008] Preferably, the application is for the prevention and control of the oriental fruit fly.

[0009] Preferably, the concentration of pilocarpine is 3000 mg / L.

[0010] The second object of the present invention is to provide the application of oxotremorine M as an insecticide synergist.

[0011] Preferably, the insecticide is fipronil or acetoprole.

[0012] Preferably, the insecticide is acetoprole.

[0013] Preferably, the application is for controlling Bactrocera dorsalis.

[0014] Preferably, the concentration of oxotremorine M is 5000 mg / L.

[0015] The present invention discloses the application of pilocarpine and oxotremorine M as insecticide synergists for controlling Bactrocera dorsalis. The virulence determination experiment on Bactrocera dorsalis adults shows that the synergistic ratio of pilocarpine to fipronil is 2.58, and the synergistic ratio of pilocarpine to acetoprole is 1.30; the synergistic ratio of oxotremorine M to fipronil is 2.03, and the synergistic ratio of oxotremorine M to acetoprole is 1.87; it is proved that pilocarpine and oxotremorine M have the effect of enhancing the insecticidal effect of the insecticides fipronil and acetoprole, and can be used as insecticide synergists for controlling Bactrocera dorsalis.

[0016] The existing synergists are mainly metabolic enzyme inhibitors, penetration enhancers, and plant-derived synergists. Long-term use of traditional synergists such as PBO has led to some pests developing resistance to their compound formulations. Therefore, exploring new pesticide synergists helps to slow down the generation of pest resistance. The present invention provides a new idea for pesticide synergists for controlling Bactrocera dorsalis, which is conducive to realizing sustainable agricultural pest control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the non-linear relationship between the mortality rate of Bactrocera dorsalis adults and the dose of fipronil.

[0018] Figure 2 It is the non-linear relationship between the mortality rate of Bactrocera dorsalis adults and the dose of acetoprole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following examples are further illustrations of the present invention rather than limitations thereof.

[0020] Example 1

[0021] 1 Materials and Methods

[0022] 1.1 Test insect sources and environmental temperature

[0023] The test insects in this experiment were sensitive strains of Bactrocera dorsalis that had been continuously raised for multiple generations in the Insect Ecology Laboratory of South China Agricultural University. Adult Bactrocera dorsalis was raised in a special 35×35×35cm wooden cage, and water and artificial feed (yeast powder: white sugar = 1:1) were changed regularly. After the adults reached sexual maturity (15 days), eggs were trapped with an oviduct filled with orange juice for 2 hours, and an appropriate amount of larval feed (made of water, banana, corn flour, yeast powder, white sugar and paper) was placed in a plastic box and spread on the bottom of the plastic box. The eggs were placed in the plastic box and raised to 3rd-instar mature larvae. The 3rd-instar mature larvae were then placed in moist fine sand for pupation. After 3 days, the pupae were sieved out of the sand with a sieve, collected in a plastic box and placed in a new cage to wait for them to emerge and continue to be raised. The emerged adults were sorted by age, sex and seed preservation according to the experimental requirements. The rearing conditions were: temperature 27°C ± 1°C, relative humidity 75% ± 1%, and photoperiod 14L:10D.

[0024] 1.2 Test reagent consumables

[0025] Pilocarpine hydrochloride (≥98%) (CAS: 54-71-7) and atropine (CAS: 51-55-8) were purchased from Selleck Biotechnology Co., Ltd., USA; oxotremorine M (CAS: 63939-65-1), fipronil (CAS: 120068-37-3), acetothrin (CAS: 209861-58-5), piperonyl butoxide (PBO, 95%) (CAS: 51-03-6) were purchased from Guangzhou Denuo Biotechnology Co., Ltd.; acetone (analytical grade AR) was purchased from Guangzhou Chemical Reagent Factory.

[0026] 1.3 Test methods

[0027] 1.3.1 Toxicity of pilocarpine and oxotremorine M to adults of Bactrocera dorsalis

[0028] The toxicity of pilocarpine and oxytremorine M fed alone to the adult fruit flies was determined. The mother solutions of pilocarpine (pilocarpine hydrochloride) and oxytremorine M were prepared with water as solvent, and 5-7 concentration gradients with mortality rates ranging from 0 to 100% were used. 20 adult fruit flies (5-7 days old) were placed in a plastic cage, with a male-female ratio of 1:1. After starvation for 4 hours, they were fed with the prepared solution, and the mortality rate was counted after 24 hours. The death standard was: the fruit flies were defined as dead when they had no movement at all when the plastic cage was tapped. The toxicity test was repeated 5 times for each concentration, with 20 adults in each repeat.

[0029] 1.3.2 Determination of the synergistic effects of pilocarpine and oxotremorine M on fipronil or acetopronil

[0030] The following method was used to determine whether pilocarpine and oxotremorine M had synergistic insecticidal effects on fipronil and acetopronil.

[0031] Prepare stock solutions of fipronil and acetamiprid at 1000 mg / L and 500 mg / L respectively, using acetone as the solvent. Dilute the stock solutions with 10% sugar water to 5 - 7 concentration gradients, and the blank control is 10% sugar water (containing the same concentration of acetone). Prepare pilocarpine (3000 mg / L, calculated based on the mass of pilocarpine hydrochloride) and oxotremorine M (5000 mg / L) at the concentration of LC 25 . Conduct experiments using pilocarpine, oxotremorine M, and a pesticide (fipronil or acetamiprid) as combinations respectively.

[0032] Take the combination of pilocarpine and fipronil as an example. Starve the Bactrocera dorsalis for 4 h, feed it with pilocarpine and fipronil together for 4 h, and then feed it with fipronil alone. The negative control is 10% sugar water (containing the same concentration of acetone); for the positive control, use piperonyl butoxide PBO. Dilute the stock solution of PBO with acetone to 10 mM, drop 2 μL of the diluted PBO on the pronotum of Bactrocera dorsalis, and feed it with fipronil 4 h later. For this group of controls, drop 2 μL of acetone on the pronotum of Bactrocera dorsalis and feed it with 10% sugar water solution 4 h later. Conduct 5 replicates for each concentration in the toxicity determination, with 20 adults in each replicate. Count the mortality rate 24 hours after feeding or dropping.

[0033] 1.4 Data processing

[0034] Use SPSS 20.0 software to systematically analyze the data for calculating the toxicity regression equation of Bactrocera dorsalis. Compare the difference between the median lethal concentration after treatment with pilocarpine or oxotremorine M and the median lethal concentration after single application using an independent - samples t - test. When the p - value is less than 0.05, the difference is considered significant.

[0035] 2 Results and analysis

[0036] 2.1 Toxicity determination of pilocarpine and oxotremorine M to adult Bactrocera dorsalis

[0037] The results of the toxicity determination of pilocarpine to adult Bactrocera dorsalis (Table 1) show that the toxicity of feeding pilocarpine alone to adult Bactrocera dorsalis is relatively low. After 24 h of treatment, the LC 50 of pilocarpine to adult Bactrocera dorsalis is 4238 (2002 - 5964) mg / L.

[0038] Table 1 Feeding toxicity of pilocarpine to adult Bactrocera dorsalis

[0039]

[0040] The toxicity of feeding oxotremorine M alone to adult Bactrocera dorsalis is extremely low. At a concentration of 5000 mg / L, the mortality rate of adult Bactrocera dorsalis after 24 h of treatment is less than 20%.

[0041] 2.1 Synergistic effect determination of pilocarpine and oxotremorine M on fipronil and acetoprole

[0042] We detected the synergistic effects of pilocarpine and oxotremorine M on fipronil and acetoprole, and the results are as follows.

[0043] The non-linear relationship between the mortality rate of adult Bactrocera dorsalis and the dose of fipronil is shown in Figure 1 . The toxicity determination results (Table 2) of pilocarpine, oxotremorine M and the insecticide fipronil on adult Bactrocera dorsalis showed that: the LC 50 of adult Bactrocera dorsalis fed with fipronil alone was 0.392 mg / L, while when mixed with pilocarpine, the LC 50 dropped to 0.152 (0.127 - 0.181) mg / L. The toxicity of the mixture of pilocarpine and fipronil to adult Bactrocera dorsalis was 2.58 times that of fipronil alone; when mixed with oxotremorine M, the LC 50 dropped to 0.188 (0.160 - 0.218) mg / L. The toxicity of the mixture of oxotremorine M and fipronil to adult Bactrocera dorsalis was 2.03 times that of fipronil alone. The synergistic ratio of pilocarpine and fipronil was 2.58, and the synergistic ratio of oxotremorine M and fipronil was 2.03. The confidence intervals of their LC 50 did not overlap with the LC 50 confidence interval of fipronil used alone. The two control groups showed that the test insects could be normally affected by the agonists. Pilocarpine and oxotremorine M significantly increased the toxicity of fipronil and had a synergistic effect.

[0044] Table 2 Feeding synergistic effects of pilocarpine and oxotremorine M on fipronil

[0045]

[0046] Note: 1. Synergistic ratio (SR): Lethal concentration at 50% mortality of single application / Lethal concentration at 50% mortality of the mixture with the synergist (pilocarpine or oxotremorine M); 2. * represents significant difference compared with the LC 50 of each insecticide alone, p < 0.05; the same as Table 3.

[0047] The non-linear relationship between the mortality rate of adult Bactrocera dorsalis and the dose of acetoprole is shown in Figure 2 . The toxicity determination results (Table 3) of pilocarpine, oxotremorine M and the insecticide acetoprole on adult Bactrocera dorsalis showed that: the LC 50 of adult Bactrocera dorsalis fed with acetoprole alone was 1.167 (1.044 - 1.294) mg / L, while when mixed with pilocarpine, the LC 50It decreased to 0.899 (0.796 - 1.001) mg / L. The toxicity of the mixture of pilocarpine and acetamiprid in feeding to Bactrocera dorsalis was 1.30 times that of feeding acetamiprid alone; when mixed with oxotremorine M, the LC 50 decreased to 0.588 (0.441 - 0.737) mg / L. The toxicity of the mixture of oxotremorine M and acetamiprid in feeding to Bactrocera dorsalis was 1.87 times that of feeding acetamiprid alone. The synergistic ratio of pilocarpine and acetamiprid was 1.30, and the synergistic ratio of oxotremorine M and acetamiprid was 1.87. The LC 50 confidence interval did not overlap with the LC 50 confidence interval of using acetamiprid alone. The two control groups showed that the experimental insects could be normally affected by the agonists. Pilocarpine and oxotremorine M significantly increased the toxicity of acetamiprid and had a synergistic effect.

[0048] Table 3 Synergistic effects of pilocarpine and oxotremorine M on acetamiprid in feeding

[0049]

Claims

1. Application of pilocarpine as an insecticide synergist.

2. The application according to claim 1, wherein The insecticide is fipronil or acetoprole.

3. The application according to claim 1, characterized in that, The insecticide is fipronil.

4. The application according to claim 1, wherein The application is for controlling Bactrocera dorsalis.

5. The application according to claim 1, characterized in that The concentration of the pilocarpine is 3000 mg / L.

6. Application of oxotremorine M as an insecticide synergist.

7. The application according to claim 6, characterized in that, The insecticide is fipronil or acetoprole.

8. The application according to claim 6, wherein The insecticide is acetoprole.

9. The application according to claim 6, wherein The application is for controlling Bactrocera dorsalis.

10. The application according to claim 6, characterized in that, The concentration of the oxotremorine M is 5000 mg / L.

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