A pesticide composition against rice dwarf disease

Abstract

The present invention belongs to the technical field of the prevention and control of rice dwarf disease, and particularly relates to a pesticide composition for resisting rice dwarf disease. A pesticidal composition, wherein the active ingredients of the pesticidal composition are binary compounded by lapachol and imidacloprid, thiamethoxam or rotenone according to a mass ratio of 1-200:150-1. The present invention realizes the resistance of rice to dwarf disease by controlling pests such as planthoppers and leafhoppers that transmit the rice dwarf disease virus. Among them, the selected compounding formula shows a synergistic effect on the biological activity of pests such as Nephotettix cincticeps, can improve the prevention and control effect on pests such as Nephotettix cincticeps, is beneficial to delaying the development of pest resistance, reducing the control cost and pesticide residues, and can provide support for the development of agents for controlling pests such as planthoppers and leafhoppers and realizing the resistance of rice to dwarf disease, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of the prevention and control of rice dwarf disease, and particularly relates to a pesticide composition for resisting rice dwarf disease. Background Art

[0002] Rice dwarf disease is a viral disease, which is divided into three types: common dwarf disease type, yellow dwarf disease type and black-streaked dwarf disease type. Rice can be infected with rice dwarf disease at the seedling stage, tillering stage and heading stage. The incidence degree of rice dwarf disease mainly depends on the population quantity of virus-carrying pests in the field in that year and the coincidence degree with the susceptible growth stage of susceptible varieties. Generally speaking, rice is more susceptible to the disease before the tillering stage, and the medium and late rice is more serious than the early rice, the hybrid rice is more serious than the conventional rice, and the transplanted seedling field is more serious than the direct-seeded field. Rice dwarf virus is mainly transmitted by piercing-sucking pests such as leafhoppers and planthoppers. When piercing-sucking pests suck the sap of virus-infected rice plants, and then transfer to suck the sap of healthy plants, the inoculation and virus transmission are completed. The virus-carrying planthoppers and leafhoppers can carry and transmit the virus throughout their lives. Therefore, the transmission of rice dwarf virus can be blocked by controlling piercing-sucking pests such as planthoppers and leafhoppers on rice, and thus the resistance of rice to dwarf disease can be achieved.

[0003] In the process of agricultural production, pests and diseases are mainly controlled by spraying pesticide agents, such as pymetrozine, imidacloprid, buprofezin, isoprocarb and fenobucarb, etc. However, with the long-term and single use of pesticide agents, the pest resistance has been accumulated, resulting in the decreasing control effect of the agents on pests year by year. Blindly increasing the application dose of pesticides can improve the control effect in a short time, but it will accelerate the development of pest resistance, and at the same time, it will also bring problems such as pesticide residues and environmental pollution.

[0004] Lapachol, CAS: 84-79-7, molecular formula: C 15 H 14 O3, and the structural formula is as follows:

[0005]

[0006] "Biological Activity Evaluation and Action Mechanism Research of Four Kinds of Natural Products" discloses the insecticidal activities of quinone compounds against Nilaparvata lugens and Mythimna separata. The research on the insecticidal activities and the structure-activity relationships of quinone compounds with different structural types shows that among naphthoquinone compounds, vitamin K1 has the best insecticidal activity, with an LC50 of 102.70 mg / L, and the rest are juglone, lapachol and shikonin, etc., with LC50 values of 110.90 mg / L, 113.81 mg / L and 211.55 mg / L respectively.

[0007] Mixing different pesticide agents is one of the convenient ways to develop new agents. Through indoor tests, the inventor found that when lapachol is mixed with imidacloprid, thiamethoxam or rotenone in a certain mass ratio, it shows a synergistic effect on pests such as Nephotettix cincticeps, etc., which can improve the control effect on pests such as Nephotettix cincticeps. There is no relevant report yet.

[0008] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art. Summary of the Invention

[0009] The purpose of the present invention is to provide a pesticide composition against rice dwarf disease, which realizes the resistance of rice to dwarf disease by controlling pests such as planthoppers and leafhoppers that transmit rice dwarf virus, and has good control effect and low cost.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] The first object of the present invention is to provide an insecticidal composition, and the active ingredients of the insecticidal composition are binary compounded by lapachol and imidacloprid, thiamethoxam or rotenone in a mass ratio of 1-200:150-1.

[0012] More specifically, the mass ratio of lapachol to imidacloprid is 1-15:3-1.

[0013] More specifically, the mass ratio of lapachol to thiamethoxam is 1-60:10-1.

[0014] More specifically, the mass ratio of lapachol to rotenone is 1-20:4-1.

[0015] The second object of the present invention is to provide the application of the insecticidal composition in controlling planthoppers and leafhoppers.

[0016] The third object of the present invention is to provide the application of the insecticidal composition in resisting rice dwarf disease.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention realizes the resistance of rice to dwarf disease by controlling pests such as planthoppers and leafhoppers that transmit rice dwarf virus. Among them, the selected compounding formula shows a synergistic effect on the biological activity of pests such as Nephotettix cincticeps, etc., which can improve the control effect on pests such as Nephotettix cincticeps, etc., is beneficial to delaying the development of pest resistance, reducing the control cost and pesticide residues, and can provide support for the development of agents for controlling pests such as planthoppers and leafhoppers and realizing the resistance of rice to dwarf disease, etc. Detailed Embodiments

[0019] The following is a clear and complete description of the technical solution of the present invention patent. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0020] Embodiment : Indoor bioactivity test

[0021] 1. Test pests

[0022] The Nephotettix cincticeps collected from rice fields were continuously tested for multiple generations with fresh and clean rice seedlings in the laboratory, and female adults that emerged 3 - 4 days were selected as the test objects.

[0023] 2. Test rice stems

[0024] The "Daofengyou 9011" rice was used for seed soaking, germination acceleration and sowing in the laboratory. Healthy and consistent rice seedlings at the tillering stage were selected, dug out with roots, washed and cut into 10 - cm - long rice stems with roots for standby.

[0025] 3. Test agents

[0026] 98% lapachol, 95% imidacloprid, 98% thiamethoxam and 95% rotenone. The above agents are all commercially available.

[0027] The test agents were prepared into single - agent mother liquors with dimethyl sulfoxide, and then multiple groups of ratios were set. Each single agent and the mixed agent of ratios were prepared into 5 mass concentration gradients according to the equal - ratio method with a 0.05% Tween - 80 aqueous solution by mass fraction for standby.

[0028] 4. Test method (refer to "NY / T 1154.11 - 2008 Guidelines for Pesticide Bioassay in the Laboratory - Part 11: Rice Stem Immersion Method for Insecticides")

[0029] The prepared rice stems were immersed in the prepared liquid medicine for 30 s and then taken out, dried, wrapped with absorbent cotton at the roots for moisture preservation, and then wrapped with plastic wrap and placed in a test tube, with 3 plants in each test tube. Each mass concentration of the liquid medicine was repeated 5 times, and a treatment containing only 0.05% Tween - 80 aqueous solution was set as the blank control. Then the test pests were transferred into the test tubes, with 15 pests in each test tube, and the tube mouths were covered with gauze.

[0030] The treatment was carried out under the conditions of temperature (25 ± 1)°C, light cycle L:D of (16:8) h, and relative humidity of 75%. After 48 h, the death situation of the test insects was checked, the total number of insects and the number of dead insects were recorded respectively, and the corrected mortality of each treatment was calculated.

[0031]

[0032]

[0033] 5. Data processing

[0034] Statistically analyze the data, and calculate the virulence regression line and the LC of each pesticide 50 . Calculate the co-toxicity coefficient (CTC value) of the mixture using Sun Yunpei's method.

[0035] 6. Synergistic evaluation

[0036] Evaluate the synergistic effect of the pesticide according to the calculated co-toxicity coefficient. When CTC ≤ 80, it is an antagonistic effect; when 80 < CTC < 120, it is an additive effect; when CTC ≥ 120, it is a synergistic effect. The results are shown in Table 1-3.

[0037] Table 1 Indoor bioassay of the combination of lapachol and imidacloprid against Nephotettix cincticeps

[0038]

[0039] As can be seen from Table 1, within the mass ratio of 1-15:3-1, the co-toxicity coefficient of the combination of lapachol and imidacloprid against Nephotettix cincticeps is greater than 120, showing a synergistic effect.

[0040] Table 2 Indoor bioassay of the combination of lapachol and thiamethoxam against Nephotettix cincticeps

[0041]

[0042] As can be seen from Table 2, within the mass ratio of 1-60:10-1, the co-toxicity coefficient of the combination of lapachol and thiamethoxam against Nephotettix cincticeps is greater than 120, showing a synergistic effect.

[0043] Table 3 Indoor bioassay of the combination of lapachol and rotenone against Nephotettix cincticeps

[0044]

[0045] As can be seen from Table 3, within the mass ratio of 1-20:4-1, the co-toxicity coefficient of the combination of lapachol and rotenone against Nephotettix cincticeps is greater than 120, showing a synergistic effect.

[0046] In summary, when lapachol is combined with imidacloprid, thiamethoxam or rotenone, the biological activity against pests such as Nephotettix cincticeps shows a synergistic effect, which can improve the control effect against pests such as Nephotettix cincticeps, is beneficial to delaying the development of pest resistance, reducing the control cost and pesticide residues, and can provide support for the development of pesticides for controlling pests such as rice planthoppers and leafhoppers and the realization of rice resistance to dwarf disease, etc.

[0047] The foregoing description of the specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the above teaching. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and modifications. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. An insecticidal composition, characterized in that, The active ingredients of the pesticidal composition are composed of a binary mixture of lapachol and imidacloprid, and the mass ratio of lapachol to imidacloprid is 1-15:3-1.

2. Use of the insecticidal composition according to claim 1 in controlling rice planthoppers and leafhoppers.

3. Use of the insecticidal composition according to claim 1 in resisting rice dwarf disease.

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