Insecticidal composition as well as preparation method and application thereof in prevention and control of brown planthopper

Abstract

The invention relates to an insecticidal composition, a preparation method thereof and an application of the insecticidal composition in prevention and control of brown planthopper, the insecticidal composition comprises the following effective components: an abscisic acid analogue AMF4 and sulfoxaflor, and the mass ratio of the AMF4 to the sulfoxaflor is 1: (1-50). When the compounding effective component ratio of the AMF4 to the sulfoxaflor is 1: 50, a synergistic effect is achieved, and the rest components have an additive effect; quantitative screening and compounding of the co-toxicity coefficient are verified again as a synergistic effect; the survival rate of nymphs of brown planthoppers, the egg laying amount of single female and the egg hatching rate are remarkably reduced by the compound medicament; the compound medicament obviously reduces the feeding of the brown planthopper; the compound agent has no toxic effect on rice growth, and the defensive enzyme activity and the resistant substance content of rice are improved. According to the insecticidal composition containing AMF4 and sulfoxaflor provided by the invention, tests show that compounding of AMF4 and sulfoxaflor has a synergistic effect, and the insecticidal composition is expected to become a novel compound medicament for preventing rice insect pests.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticide compounding, and particularly relates to an insecticidal composition containing abscisic acid analog AMF4 and sulfoxaflor, a preparation method thereof, and an application thereof. Background Art

[0002] The brown planthopper, Nilaparvata lugens, belongs to the Delphacidae family of Hemiptera and is an important pest threatening the safe production of rice in China. The brown planthopper mainly damages rice by sucking and laying eggs, and its secretions covering the plant surface can also affect the photosynthesis of rice. In addition, the brown planthopper can also transmit rice virus diseases such as grassy stunt disease and ragged stunt disease. At present, the control of the brown planthopper mainly relies on chemical pesticides. However, the long-term, large-scale, and unscientific use of insecticides has caused the field population of the brown planthopper to develop varying degrees of resistance to a variety of commonly used insecticides, resulting in a significant decline in the field control effect of insecticides. The problem of insecticide resistance poses a severe challenge to the scientific and effective control of the brown planthopper, and the development of highly efficient and low-toxic pesticides takes a long time. Therefore, the scientific and reasonable use of existing insecticides to delay the development of their resistance is crucial for the prevention and control of the brown planthopper.

[0003] Sulfoxaflor is a new type of neonicotinoid insecticide developed by Dow AgroSciences LLC in the United States. It has a unique sulfoximine group and is therefore also known as a sulfoximine insecticide. According to its mode of action, sulfoxaflor is classified by the Insecticide Resistance Action Committee (IRAC) as a Group 4 family of nicotinic acetylcholine receptor competitive modulators (nAChR competitive modulators). Since it differs from traditional neonicotinoid insecticides (Group 4a), such as imidacloprid and nitenpyram, in chemical structure and metabolic resistance mechanisms, it is classified as Group 4c, and it is the only active ingredient in this group. Sulfoxaflor has good permeability and systemicity in plants, and at the same time has a certain contact-killing effect on pests, and can effectively control pests such as brown planthoppers, whiteflies, aphids, and thrips. With the wide use of sulfoxaflor, the resistance of pests to this agent has also been reported. In order to reduce the use of pesticides and delay the emergence of resistance, the method of pesticide compounding has gradually attracted people's attention.

[0004] Pesticide compounding refers to the mixing and use of two or more pesticides to achieve effects such as enhancing the efficacy, expanding the control spectrum, slowing down the emergence of resistance, and reducing the cost of using pesticides. Reasonable implementation of pesticide compounding is one of the effective ways to increase the scientific use of pesticides. At present, the pesticide compounding technology in China has been widely applied and achieved certain results. In the future, the research and development, popularization, and application of pesticide compounding technology should be further strengthened, and attention should be paid to scientific and reasonable use to achieve the sustainable development of agricultural production and environmental protection.

[0005] Abscisic acid (ABA) is unstable and cannot be presented in the form of agrochemical products. As a substitute for ABA, the ABA analog AMF4 (ABA mimic 1 tetrafluoro derivative) can not only improve stress resistance (such as drought resistance), but also has no pollution to the environment, high safety, and can reduce the use of pesticides. In addition, as a plant growth regulator itself, it can promote the growth and yield increase of rice. Therefore, exploring the effect of the compounding of AMF4 and sulfoxaflor on the control of the brown planthopper is of great significance for the green control of the brown planthopper in rice fields and solving the increasingly serious pest resistance problem. Summary of the Invention

[0006] Technical problem to be solved: The object of the present invention is to address the above-mentioned existing problems and apply the current pesticide compounding technology system to provide an insecticidal composition containing the abscisic acid analog AMF4 and sulfoxaflor, its preparation method, and its application in pest control.

[0007] Technical solution: An insecticidal composition comprising the active ingredients abscisic acid analog AMF4 and sulfoxaflor, wherein the mass ratio of AMF4 to sulfoxaflor is 1:(1 - 50).

[0008] Preferably, the mass ratio of the above-mentioned AMF4 to sulfoxaflor is 1:50.

[0009] The above-mentioned pest is the brown planthopper (Nilaparvata lugens).

[0010] A method for controlling the brown planthopper, comprising the step of applying the above-mentioned insecticidal composition to rice plants.

[0011] The above-mentioned application method is the rice stem dipping method, and the brown planthopper is in the 3rd instar nymph stage when applying.

[0012] In the above-mentioned composition, the mass concentration of AMF4 is 0.087 - 4.441 mg / L, and the mass concentration of sulfoxaflor is 1.00 - 5.550 mg / L.

[0013] Preferably, the total mass concentration of the above-mentioned composition is 0.087 + 1.00 mg / L to 4.441 + 5.550 mg / L.

[0014] The preparation method of the above-mentioned insecticidal composition is to separately dilute AMF4 and sulfoxaflor and then mix them according to the mass ratio, and the mass ratio is 1:(1 - 50).

[0015] A pesticide formulation comprising the above-mentioned insecticidal composition and an agriculturally acceptable carrier.

[0016] Beneficial effects: The insecticidal activities of AMF4 and sulfoxaflor against Nilaparvata lugens were determined by the rice stem immersion method; the combined insecticidal activity of the AMF4 and sulfoxaflor mixture against Nilaparvata lugens was evaluated by the co-toxicity coefficient method. The results showed that when the ratio of the active ingredients of the AMF4 and sulfoxaflor mixture was 1:50, it had a synergistic effect, and the rest were additive effects; the quantitative screening of the mixture by the co-toxicity coefficient method was verified again to be a synergistic effect; the mixture significantly reduced the nymph survival rate, the number of eggs laid per female, and the egg hatching rate of Nilaparvata lugens; the mixture significantly reduced the feeding of Nilaparvata lugens; the mixture had no toxic effect on rice growth and increased the activities of rice defense enzymes and the contents of resistant substances. The present invention provides an insecticidal composition containing AMF4 and sulfoxaflor. Through experiments, it is found that the mixture of AMF4 and sulfoxaflor has a synergistic effect and is expected to become a new mixture for preventing rice insect pests. Description of the Drawings

[0017] Figure 1 Effects of the AMF4 and sulfoxaflor mixture treatment on the nymphs of Nilaparvata lugens; among them, A is the survival rate, B is the number of eggs laid per female, and C is the effect on the egg hatching rate.

[0018] Figure 2 Effects of the AMF4 and sulfoxaflor mixture treatment on the feeding of Nilaparvata lugens; among them, A is the feeding tendency and B is the amount of honeydew.

[0019] Figure 3 Effects of the AMF4 and sulfoxaflor mixture treatment on the growth of rice; among them, A is the plant height of rice, B is the weight of the above-ground and underground parts, and C is the root-shoot ratio.

[0020] Figure 4 Effects of the loss after Nilaparvata lugens feeds on the rice treated with the AMF4 and sulfoxaflor mixture; among them, A is the average damage level and B is the functional loss index.

[0021] Figure 5 Effects of the AMF4 and sulfoxaflor mixture treatment on the activities of rice defense enzymes; among them, A is the activity of peroxidase (POD), B is the activity of catalase (CAT), C is the activity of superoxide dismutase (SOD), and D is the activity of polyphenol oxidase (PPO).

[0022] Figure 6 Effects of the AMF4 and sulfoxaflor mixture treatment on the resistant substances of rice; among them, A is the flavonoid content and B is the total phenol content. Detailed Embodiments

[0023] The present invention will be further described below in conjunction with the drawings and the description of the drawings. The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples can all be obtained from commercial channels unless otherwise specified.

[0024] The plant material is the conventional rice variety Nanjing 46; the brown planthopper population is reared on the rice TN1 strain.

[0025] Example 1

[0026] The sulfoxaflor technical was formulated into a stock solution of 100 mg / L with a 0.2 wt.% DMSO solution. Using the 0.2 wt.% DMSO solution as a control, the sulfoxaflor concentrations for the tests were 16.00, 12.00, 8.00, 4.00, 2.00, and 1.00 mg / L. The rice was treated by the rice stem dipping method. After 1 day of dipping treatment, 20 third-instar nymphs of the same batch with similar growth conditions and starved for two hours were introduced onto each treated rice plant. Each treatment had 10 replicates. After 72 h, the mortality rate of the test insects was counted. As shown in Table 1, the median lethal concentration LC 50 of sulfoxaflor was 5.55 mg / L, χ 2 = 3.599 < 7.814, and the correlation coefficient was 0.966.

[0027] Example 2

[0028] The AMF4 and the sulfoxaflor stock solution were respectively diluted into pesticides with concentrations of 4.441 mg / L and 5.550 mg / L using a 0.2 wt.% DMSO solution. By the co-toxicity factor method, the types of pesticide combinations with significant synergistic effects were screened. Different concentration ratios of the pesticides were obtained by mixing them at mass ratios of 1:1, 1:2, 1:3, 1:4, 1:5, 1:10, 1:20, 1:30, 1:40, and 1:50. Each concentration had 10 replicates. After 1 day of spraying treatment, 20 third-instar nymphs of the same batch with similar growth conditions and starved for two hours were introduced onto each treated rice plant. Each treatment had 10 replicates. After 72 h, the mortality rate of the test insects was investigated. As shown in Table 2: when the active ingredient ratio of AMF4:sulfoxaflor = 1:50, there was a synergistic effect, and the co-toxicity factor was 31.86. The remaining mixing ratios were additive effects. Therefore, the mixing ratio of the active ingredients of AMF4 and sulfoxaflor at 1:50 was initially determined to carry out subsequent tests. The expected mortality rate and co-toxicity factor were calculated according to the following formulas.

[0029] Theoretical mortality rate (%) = Actual mortality rate at the LC 50 value of pesticide A × Proportion of pesticide A + Actual mortality rate at the LC 50 value of pesticide B × Proportion of pesticide B

[0030] Co-toxicity factor = (Actual mortality rate - Theoretical mortality rate) / Theoretical mortality rate × 100

[0031] Example 3

[0032] The medicament with a mass ratio of 1:50 was diluted 4 times in equal proportion with 0.2 wt.% DMSO solution at 2 times for the experiment. Using 0.2 wt.% DMSO solution as a control, indoor toxicity determination was carried out by the same method as in step (1), and toxicity regression statistics were performed and the co-toxicity coefficient was calculated according to the formula. As shown in Table 3, the co-toxicity coefficient of AMF4 and sulfoxaflor at a compounding ratio of 1:50 of the active ingredients was 209.106, showing a synergistic effect. Therefore, the optimal compounding formula of the active ingredients for controlling Nilaparvata lugens was determined as AMF4:sulfoxaflor = 1:50.

[0033] The toxicity index (ATI) of the tested medicament = (LC of the standard medicament 50 / LC of the tested medicament 50 ) × 100%

[0034] The theoretical toxicity index (TTI) of the compounded medicament = (the toxicity index of medicament A × the percentage content of medicament A in the compounded medicament) + (the toxicity index of medicament B × the percentage content of medicament B in the compounded medicament)

[0035] The co-toxicity coefficient (CTC) = (ATI / TTI) × 100

[0036] Example 4

[0037] Using 0.2 wt.% DMSO as a control, in addition, two other treatment groups were made with the medicaments corresponding to the mass concentrations of AMF4 and sulfoxaflor in the compounded medicament with a mass ratio of 1:50 by the rice stem immersion method. The female and male adults of Nilaparvata lugens were placed in advance on clean rice seedlings of TN1 strain to mate and lay eggs. The nymphs hatched within 12 h were transferred into cups containing rice seedlings sprayed 1 day ago. 20 newly hatched nymphs were inoculated in each treatment, and each treatment was repeated 10 times. The death of nymphs was observed and recorded. As Figure 1 shown in A, the survival rates of the nymphs of Nilaparvata lugens after treatment with sulfoxaflor and the compounded medicament decreased significantly. Compared with the control, they decreased by 38.75% and 56.25% respectively.

[0038] Example 5

[0039] Using 0.2 wt.% DMSO as a control, in addition, two other treatment groups were made with the medicaments corresponding to the mass concentrations of AMF4 and sulfoxaflor in the compounded medicament with a mass ratio of 1:50 by the rice stem immersion method. Each treatment of rice was ensured to have no eggs before inoculation, covered with a glass tube, and after spraying treatment for 1 day, a pair of adults emerged on the same day were inoculated on each seedling and sealed with a sponge. After inoculating the insects, the survival rate and egg-laying situation of the adults were observed daily. After the nymphs hatched, their numbers were counted every day until no new nymphs hatched. The rice stems in the tube were cut off, and the number of unhatched eggs of Nilaparvata lugens in the rice leaf sheaths was counted under a dissecting microscope. The hatching rate and total egg production of Nilaparvata lugens eggs were calculated according to the following formula. Each treatment was repeated 10 times. AsFigure 1 As shown in B and C, after treatment with AMF4, sulfoxaflor, and the compound agent, compared with the control, the egg-laying amounts of female brown planthoppers decreased significantly by 15.69%, 26.41%, and 49.77% respectively ( Figure 1 : B). The situation of the hatching rate was similar to that of the nymph survival rate. After treatment with AMF4, there was no significant difference in the hatching rate of eggs compared with the control. However, after treatment with sulfoxaflor and the compound agent, the hatching rates decreased by 27.63% and 56.60% respectively compared with the control ( Figure 1 : C).

[0040] Hatching rate = Number of hatched nymphs / (Number of hatched nymphs + Number of unhatched eggs)

[0041] Example 6

[0042] When the rice was hydroponically cultured to the tillering stage, 4 rice plants with consistent growth were fixed on a black flat sponge in a 3×3 cm square, placed in a cup and continued to be hydroponically cultured for 3 days. 0.2 wt.% DMSO was used as the control. In addition, the rice stem dipping method was used to make two other treatment groups with the corresponding mass concentrations of AMF4 and sulfoxaflor in the compound agent at a mass ratio of 1:50. One day after the spraying treatment, 30 starved brown planthopper nymphs for 2 hours were placed in the center of the square, covered with a transparent plastic cover on the outside, and the top was covered with a sponge. At 1, 2, 4, 8, 12, and 24 hours after inoculating the brown planthoppers, the brown planthoppers on the three treatments and the control plants were observed and counted. The experiment was repeated 12 times. Figure 2 : A The results showed that at all time points, the three treatments were significantly lower compared with the control. Compared with the control, after treatment with AMF4, the feeding tendencies of brown planthoppers decreased by 40.20%, 41.51%, 48.70%, 55.00%, 57.81%, and 61.31% respectively at 1, 2, 4, 8, 12, and 24 hours after insect inoculation; after treatment with sulfoxaflor, the feeding tendencies of brown planthoppers decreased by 59.80%, 63.21%, 66.96%, 65.83%, 72.66%, and 75.18% respectively at 1, 2, 4, 8, 12, and 24 hours after insect inoculation; after treatment with the compound agent, the feeding tendencies of brown planthoppers also decreased by 64.71%, 68.87%, 75.65%, 79.17%, 82.03%, and 88.32% respectively at 1, 2, 4, 8, 12, and 24 hours after insect inoculation. One day after the brown planthoppers fed on the rice treated with the three treatments, the honeydew excretion amount decreased significantly. Compared with the control, the honeydew amounts after feeding on the rice treated with AMF4, sulfoxaflor, and the compound agent decreased by 40.74%, 64.05%, and 69.45% respectively ( Figure 2 : B). The results showed that brown planthoppers preferred to feed on the rice in the control group.

[0043] Example 7

[0044] Using 0.2 wt.% DMSO as a control, in addition, the rice stem dipping method was used to prepare two other treatment groups with the medicaments of AMF4 and sulfoxaflor at a mass ratio of 1:50 in the compound medicament corresponding to their mass concentrations. During the tillering stage of rice, the five-point sampling method was adopted. For each treatment group, 8 sample plants were selected to measure the plant height of each treatment group. The rice plants were grouped according to the treatment groups, and the upper part of the roots and the roots were weighed separately to calculate the root-shoot ratio and the weights of the above-ground part and the underground part. As Figure 3 shown in A, after treating rice with AMF4 and the compound medicament for 7 days, there was no significant change in the plant height of the rice plants compared with the control group, but the plant height of the AMF4 treatment group was significantly higher than that of the sulfoxaflor treatment group, by 17.42%. As Figure 3 shown in B, compared with the control group, there was no significant difference in the above-ground weight of the rice after treatment with AMF4 and the compound medicament, while the above-ground weight of the rice decreased significantly after treatment with sulfoxaflor, by 12.29%; there was no significant difference in the underground weight of the rice after treatment with AMF4, sulfoxaflor, and the compound medicament; the results showed that the sulfoxaflor treatment group had the greatest impact on the above-ground weight of the rice. As Figure 3 shown in C, compared with the control group, there was no significant difference in the root-shoot ratio of the rice after treatment with AMF4 and the compound medicament, while the root-shoot ratio of the sulfoxaflor treatment group was significantly higher than that of the control group, increasing by 8.38%.

[0045] Example 8

[0046] Using 0.2 wt.% DMSO solution as a control, after treating the three kinds of treatment liquid medicines on rice stems by the rice stem dipping method for 1 day. Take 30 3rd-instar brown planthopper nymphs, starve them for 1 h, introduce them into each rice plant, and seal the upper part of the transparent plastic tube with gauze, and observe regularly. There are 10 replicates for each treatment. Cultivate in an artificial greenhouse, and conduct visual grading according to the international unified standard. When the damage level of one of the rice plants reaches level 9, suck out the remaining brown planthoppers with a suction tube, record the damage level of each rice plant, and calculate the average damage level.

[0047] The determination of the plant functional loss index refers to the method of Panda and Heinrichs (1983) and is slightly improved. Mark the rice plants at the end of recording the average damage level, cut them off at the root and wash them, blanch them in an oven at 110 °C for 20 min, and dry them at 70 °C to constant weight, and weigh them separately. Calculate the functional plant loss index (FPLI) to represent the damage degree of the rice plants and evaluate the tolerance of rice to brown planthoppers.

[0048] The determination results of the average damage level showed that after the brown planthoppers fed, the plants treated with AMF4, sulfoxaflor, and the compound medicament showed lower damage levels than the control, and there were significant differences between the sulfoxaflor and the compound medicament treatment groups, which were significantly lower than the control by 38.36% and 52.05% respectively ( Figure 4: A). Further analyzing the functional loss index of rice, it was found that after the feeding of Nilaparvata lugens, there were significant differences between the plants treated with sulfoxaflor and the compound agent and the control, which were 35.12% and 49.26% lower than the control respectively ( Figure 4 : B). It indicates that the losses of the plants treated with sulfoxaflor and the compound agent after the feeding of Nilaparvata lugens are less than those of the control, and the loss of the sulfoxaflor treatment group is smaller.

[0049] Example 9

[0050] Using the 0.2 wt.% DMSO solution as the control, after treating the three kinds of treatment liquid medicines by the rice stem dipping method for 7 days, the activities of defense enzymes in the above-mentioned treated rice were measured. Among them, there were significant differences in peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) between the treatment groups of AMF4, sulfoxaflor and the compound agent and the control group, and the changing trends of the activities of the three enzymes were similar. The enzyme activities of each treatment group were significantly enhanced compared with the control group ( Figure 5 : A - C); the POD activity increased by 15.19%, 69.93% and 101.60% respectively compared with the control group; the CAT activity increased by 31.47%,

[0051] 50.88% and 54.91% respectively compared with the control group; the SOD activity increased by 32.85%, 29.52% and 39.03% respectively compared with the control group; there was no significant difference in polyphenol oxidase (PPO) between the treatment groups and the control group ( Figure 5 : D).

[0052] Example 10

[0053] Using the 0.2 wt.% DMSO solution as the control, after treating the three kinds of treatment liquid medicines by the rice stem dipping method for 7 days, the activities of resistance substances in the above-mentioned treated rice were measured. After treating the rice plants with AMF4, sulfoxaflor and the compound agent, the flavonoid contents in each treatment group were significantly higher than those of the control, and increased by 123.65%, 29.36% and 155.67% respectively compared with the control ( Figure 6 : A); after treating the rice plants with AMF4, sulfoxaflor and the compound agent, the total phenol contents in the rice increased. Among them, the treatment groups of AMF4 and the compound agent increased significantly, by 7.63% and 5.45% respectively compared with the control ( Figure 6 : B). It shows that the treatment with the compound agent can significantly increase the resistance substances flavonoid and total phenol in rice.

[0054] Table 1 Indoor toxicity determination results of sulfoxaflor against Nilaparvata lugens

[0055]

[0056] Table 2 Mortality of Nilaparvata lugens under different compounding ratios of AMF4 and sulfoxaflor

[0057]

[0058] (Note: Co-toxicity factor ≥ 20 indicates synergistic effect; co-toxicity factor ≤ -20 indicates antagonistic effect; -20 < co-toxicity factor < 20 indicates additive effect.)

[0059] Table 3 Indoor toxicity determination of compound pesticides against Nilaparvata lugens

[0060]

[0061] The above embodiments describe the preferred embodiments of the present invention and do not limit the present invention. Without departing from the spirit or scope of the present invention, technical improvements and equivalent substitutions made by relevant technical personnel to the present invention are within the protection scope of the present invention.

Claims

1. An insecticidal composition, characterized in that, Comprising the active ingredients abscisic acid analogue AMF4 and sulfoxaflor, wherein the mass ratio of AMF4 to sulfoxaflor is 1:(1 - 50).

2. The pesticidal composition according to claim 1, wherein The mass ratio of AMF4 to sulfoxaflor is 1:

50.

3. The pesticidal composition according to claim 1, characterized in that, The pest is Nilaparvata lugens ( Nilaparvata lugens ).

4. A method for controlling brown planthopper, characterized in that, Including the step of applying the insecticidal composition according to any one of claims 1 - 3 to rice plants.

5. The method according to claim 4, characterized in that, The application method is the rice stem dipping method, and the brown planthopper is in the 3rd instar nymph stage during application.

6. The pesticidal composition according to any one of claims 1-3, characterized in that, The mass concentration of AMF4 in the composition is 0.087 - 4.441 mg / L, and the mass concentration of sulfoxaflor is 1.00 - 5.550 mg / L.

7. The pesticidal composition according to claim 6, wherein The total mass concentration of the composition is 0.087 + 1.00 mg / L to 4.441 + 5.550 mg / L.

8. A method for preparing the insecticidal composition according to any one of claims 1 to 3, characterized in that, Prepared by separately diluting AMF4 and sulfoxaflor and then mixing them according to the mass ratio, and the mass ratio is 1:(1 - 50).

9. A pesticide formulation, characterized in that, Comprising the insecticidal composition according to any one of claims 1 - 3 and an agriculturally acceptable carrier.

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