WO2005029958A1

WO2005029958A1 - Use of anthraquinone derivatives as pestcides for controlling plant diseases

Info

Publication number: WO2005029958A1
Application number: PCT/CN2004/000988
Authority: WO
Inventors: Dazhao Yu; Xiaojun Yang; Hanwen Ni; Lijun Yang; Shaonan Wang; Yongyu Zhao; Hanyi Zhang
Original assignee: Institute For Plant Protection And Soil Science, Hubei Academy Of Agricultural Sciences
Priority date: 2003-08-29
Filing date: 2004-08-25
Publication date: 2005-04-07
Also published as: CN1248578C; CN1515152A

Abstract

The invention relates to use of anthraquinone derivatives as effective ingredients of pesticides for controlling fungal diseases of plants. The said pesticides comprise one or more compounds selected from ten species anthraquinone derivatives, which have obviously preventive and therapeutic effect against many plant diseases and can be used to control diseases caused by fungi of Sphaerotheca, Erysiphe, Blumeria, Fusarium, Sclerotinia, Pyricularia, Rhizoctonia, Colletotrichum, Botrytis, Yerticillium, Alternaria, in various cereal crops, economic crops, vegetables, fruit trees, melons and so on. They also have low toxicity, low residual and good environment compatibility.

Description

Application of anthraquinone derivatives as pesticides for plant diseases

Technical field

The present invention relates to the application of anthraquinone derivative plant protection compounds as effective ingredients as pesticides for controlling plant fungal diseases. Background technique

The infection process of plant pathogens is a continuous process, which is usually divided into three stages: invasion, incubation and disease. The aspirator is the only scab formed by the fungus in the host cells. It plays an important role in the nutrient absorption, transport, and determination of the parasitic relationship between the fungus and the host. For example: The histopathological study of the interaction between wheat rust and host indicated that the development of wheat rust fungi is divided into four stages: suction cell mother cell formation, invasion plug formation, suction neck extension and suction body expansion. Under the conditions of 6 hours, germination occurred, 12 hours most germ tubes invaded the stomata and then produced sucker mother cells. 24 hours, the sucker mother cells invaded mesophyll tissue to produce finger sucker progenitors and differentiated into elongated sucker necks and spherical sucker bodies. The continuous growth of the silk continued to divide the techniques, and continued to differentiate and expand to form a spore heap (Li Zhenqi, chief editor of Zeng Shimai, China Wheat Rust Disease, China Agricultural Press, 2002.20-24.109-110).

In the past, chemical pesticides were mainly used to control plant pathogenic fungi, but these chemical pesticides have problems such as large pollution, poor compatibility with the environment, and the susceptibility of pathogenic bacteria to drug resistance.

Anthraquinone-derived compounds are common plant secondary metabolites that exist in plants. They are usually found in some species of the family Amaranthaceae, Ambrosidae, Rhamnaceae, Rubiaceae, and anthraquinone derivatives are the active ingredients of commonly used Chinese medicine. Used as a laxative in clinical Chinese medicine and has strong antibacterial activity (anti-Staphylococcus aureus, Bacillus subtilis) and anti-cancer activity. Among them, rhein has the strongest antibacterial activity, and emodin has the strongest effect on inhibiting human liver cancer cells. Chemistry Shanghai Science and Technology Press 1997, 196-197 X However, their functions in plants have not yet been understood.

The technical problem to be solved by the present invention is to make full use of the antifungal activity of anthraquinone-derived compounds and use it as a pesticide for controlling diseases of plants, especially crops, to effectively prevent fungal infection of plants.

The invention is based on the development of a new type of natural active substance, which verifies that the anthraquinone derivative has anti-phytopathogenic fungal activity, and provides a new application for the anthraquinone derivative in the field of pesticides.

The anthraquinone derivative pesticide of the present invention contains any one or more of the following anthraquinone derivative compounds: Its chemical structural formula is:

Confirm this

The invention uses organic solvent extraction, extraction, column chromatography, and high-pressure liquid chromatography known in the technical field from Rumex patient i. Polygonum mitiflonim Cassia obtusifolia

The above 10 kinds of anthraquinone derivatives were obtained.

The above 10 anthraquinone-derived compounds were extracted from a variety of plants. Through a large number of indoor and outdoor tests, it was found that these anthraquinone-derived compounds have obvious preventive and therapeutic effects on a variety of plant diseases and can be used to control various food crops and cash crops , Vegetables, fruit trees, melons and other diseases caused by fungi, including: monofilament genus "¾? / ^ / ^ ₀ , white powder genus Erj« ½, Brinell powder genus S / M en'c fusarium ¾sw ' w, Sclerotinia 5Werat'a, Pyrus sp. 7'cw / a'a, Rhizoctonia Rhizoctonia Colletotrichun Vitis Botrytis Verticillium Alternaria Altemaria fungi caused by fungi.

For example: (Compound 1) Emodin-6, 8-dimethylether, Modin-6, 8-dimethylether, (Compound 7) Emodin-1, 6-dimethylether, Emmodin 1, 1, 6-dimethylether, (Compound 9) Xanthorin—5-methylether and others have significant antibacterial activity against wheat powdery mildew (S / w era graminis f.sp.trtc). Histological staining observations showed that spraying treatment could significantly inhibit the germination of powdery mildew conidia. The spraying treatment of conidia could not germinate 4 hours after inoculation, but the water control could germinate normally. 8, 24, 48 and 72 after inoculation The spore germination rate of the hour spraying treatment was significantly lower than the germination rate of the clear water control treatment by more than 2 times; the bud tube formed after the spraying treatment could hardly form the normal attachment spores, and more than 80% of the spores appeared as slender and tubular deformed attachments; The formed normal attached spores can scarcely form further suckers, and have already formed The resulting aspirator becomes significantly smaller. After spray treatment, the spore production of single colony was significantly lower than that of the control with clear water.

The anthraquinone-derived compounds of the present invention can also be used to control wheat powdery mildew, powdery mildew of cucumber (cucurbita powdery mildew, gardenia powdery mildew), cucumber gray mold, rice blast, rice sheath blight, cotton wilt, cotton yellow Pesticides against wilt, rape sclerotinia, tomato blight, pepper anthracnose, tobacco red spot disease.

The ten anthraquinone-derived compounds described in the present invention have significant antibacterial activity. They are secondary metabolites of plants, which can be derived from plants or artificial synthetics.

When an antifungal pesticide using the anthraquinone-derived compound of the present invention as an active ingredient is manufactured, an auxiliary agent such as an agriculturally acceptable carrier, a surfactant, and the like can be used to make a common pesticide known in the technical field. Various carriers and various dosage forms such as solid phase, liquid phase, emulsifier and dispersant. Such as wettable powders, emulsifiable concentrates, microemulsions, aqueous preparations, suspensions, and water-dispersible granules. Each of the above anthraquinone-derived compounds may be used singly or in combination (including two types), and the proportion of the active ingredients in each preparation is 5-90% by weight, and may be appropriately increased or decreased according to different purposes of use.

The pesticide application of the present invention is suitable to be applied once before the disease is about to occur, and then used 1-2 times every 7-10 days according to the development of the disease.

The beneficial effect of the present invention is that the medicament using anthraquinone derivative as an active ingredient is a secondary metabolite produced by a plant during growth and development, and is a new type of antifungal agent, which can successfully prevent fungi from affecting the plant. Infestation. It has the characteristics of low toxicity, low residue, and environmental compatibility. It is a new type of biological pesticide, and has obvious preventive and therapeutic effects on a variety of plant diseases, especially agricultural diseases.

detailed description

In order to better understand the present invention, the following describes the substantial content of the present invention with reference to the embodiments of the present invention, but the content of the present invention is not limited thereto.

Example 1: Study on the effect of the derivatized compound 7 (emodin-1,6-dimethylether Emodin-1,6-dimethylether) of the present invention on the development of powdery mildew in wheat seedling stage.

1. Bacterial strain: wheat powdery mildew (/ w er ^ gra? M'7 ^ f. Sp. Tn c) strain Nol4, which was determined to be highly pathogenic from 10 main wheat varieties in Hubei.

2. Wheat varieties: Zheng 98 (shows affinity with No l 4 strain).

3. Cultivation of wheat seedlings: Cultivate consistent wheat seedlings in a 30 cm flower bowl in a light soil incubator of 1 soil at 1 ° C, 15 plants per bowl, and test when the wheat seedlings grow to one leaf and one heart. Sampling and microscopy were performed after inoculation. The method of inoculating isolated leaf segments is as follows: first leaves are cut into 3cm leaf segments and placed on 0.5% water agar plates containing 50 ug / ml benzimidazole, with 8 leaf segments per plate.

The derivative compound 7 is dissolved with 0.1 ml of benzene and emulsified with 20 ul of emulsifier 656H, and then prepared into a liquid medicine with water, and the prepared wheat seedlings and isolated leaf segments are processed in a micro-electric rotating spray tower, 3 repetitions each time. The total spray volume is 3ml. After the liquid is dried, the powdery mildew is inoculated.

Vaccination: Vaccination is used for the above two methods. The susceptible wheat variety "Zheng 98" was used to propagate powdery mildew Nol4, the age of the bacteria was 14 days, and the inoculated spore concentration was 400 / cm ^2. After inoculation, it was left to stand for 10 minutes, placed at 1 ° C and 1 ° C, RH = 90% ₅ 16000k. Light culture room. Sample processing and observation: Using Wolf's rapid staining method, the sampling leaf section was placed in a ethanol-trichloromethane (75: 25v / v) mixed solution containing 0.15% trichloroacetic acid, and decolorized at 70 ° C for 20min. The leaf sections were made transparent, and then stained with a 15% trichloroacetic acid aqueous solution and 0.6% Coomassie brilliant blue R-205 (dissolved in 99% methanol) (1: 1: v / v) for 20 min. After rinsing with tap water, store in glacial acetic acid: glycerol: water (5: 20: 75, v / v / v), and observe the molecular spore germination rate, attachment cell formation rate, deformity rate, aspirator primitive and aspirator development under an optical microscope. situation.

Effects of Derivative Compound 7 on the development of wheat powdery mildew

Example 2 Study on the Inhibitory Effect of Derivative Compounds of the Invention on Wheat Powdery Mildew

The method of Example 1 using the same embodiment will be Erysiphe species and cultivation of wheat seedlings, the compounds 1-10 were derived from ethanol, after dissolving benzene were diluted to different concentrations (100ug / g ~ 1.25ug / g ) measured for EC ₅₀ Value, and its potted plant seedling activity was measured using a concentration of 6.25ug / g. The isolated leaf sections and plant seedlings were placed in a micro-spraying tower, and the spraying amount was 3 ml per concentration, three times. After 6 hours of spraying, the powdery mildew was inoculated. After 6 days of incubation in the culture room, the number of infection points of powdery mildew on each leaf segment and leaf was recorded, and the bacteriostatic effect (%) of each treatment was calculated. The results show that compounds 1-10 all have good bacteriostatic effects, in which (compound 1) emodin-6, 8-dimethyl ether, (compound 7) emodin-1, 6-dimethyl ether, (compound 9) Xanthorin-5-methylether has excellent control effects.

Example 3: Study on the Inhibitory Effect of Derivative Compounds of the Invention on Rice Blast Fungus

1. Bacterial strain: Pyricularia grisea w02-l (Affinity with Lijiang New Mission Black Valley)

2. Rice varieties: Lijiang New Mission Heigu (does not contain any anti-blast genes)

The spore germination method was used to determine the inhibitory activity of 1-10 derived compounds against Magnaporthe grisea. The tomato oatmeal juice medium was used to cultivate w02-l, and each liter of the medium contained 150 ml of tomato juice, 750 ml of oat juice (30 g oatmeal with 1000 ml of water and boiled for 20 min, double-layer gauze filtration), and 18 g of agar. After sterilization, insert the mycelia of w02-1 and incubate for 2 days under 25 ° C light. Aerial mycelium interrupted with sterile swabs, cultured for 1-2 days with the spore sterile water, gauze filtered, diluted spore suspension to ^¹ χ 10 ό cells / ml until use. After dissolving 1-10 compounds with ethanol and benzene, dilute them to different concentration gradients of 100ug / g-2ug / g, mix the bacterial solution and spore suspension in equal volumes, and the drug concentration is 50ug / g-lug / g. 40 ul of liquid spore mixture was placed on a concave glass slide, and three replicates were cultured in the dark at 25 ° C for 18 hours. When the blank control spores germinated above 90%, the spore germination rate of each treatment was investigated, and the bacteriostatic rate and EC ₅₀ value were calculated.

The in vitro leaf segment method was used to determine the inhibitory effect on rice blast. Seed soaking and germination pot planting rice Lijiang New Mission Heigu, when the 5 leaves and 1 heart of the rice, the 5th leaf was cut off and the tail was removed, and 5cm long leaf sections were placed in each processing petri dish, 5-7 sections per dish, first 1-10 compounds were sprayed at a concentration of 24 ug / g of the compound. The spray volume was 5 ml, and each treatment was repeated 3 times. After 24 hours, the isolated leaf segments were inoculated with lx 10 ⁶ spores per ml. 5ml of bacterial solution was sprayed quantitatively, hydrated and cultured under the dark condition of 25 ° C for 36h, and then irradiated for 36h, then investigated the incidence and calculated the control effect. Control effect% = (number of control lesions-number of treated lesions) / number of control lesions X 100. The results showed that compounds 1-10 also had a good antibacterial effect on rice blast. In addition to compounds 1, 7, 9 which still have excellent control effects, (compound 2) C-hydroxyemodin, (compound 3) (0-hydroxyemodin-8-methyl ether, (compound 4) emodin-8- Methyl ether, (compound 5) 2-acetylemodin, (compound 8) emodin-6-ether also have good control effects.

Example 4: 5% wettable powder

5 parts of any one of the compounds 1-10 of the present invention are mixed with 10 parts of WPA-9503 compounding aid and 85 parts of diatomaceous earth by weight, and crushed to obtain 100 parts of a wettable powder. Example 5: 5% emulsion

100 parts of the emulsion was obtained by mixing and dissolving 5 parts of any of the derivatized compounds of 1, 7, 9, 10 of the present invention with 75 parts of benzene and 20 parts of 656H compounding aid by weight.

5 parts of any of the derivatized compounds of 2-6, 8 of the present invention were mixed and dissolved with 75 parts of ethanol and 20 parts of 656H compounding aid by weight to obtain 100 parts of an emulsion. Example 6: Derivative Compound 7 (Emodin-1, 6-dimethyl ether) of the present invention for the control of wheat powdery mildew and cucumber powdery mildew

The use of the 5% wettable powder of this Example 4 was started before the powdery mildew became manifested, and then applied again a total of two times after 10 days, which could effectively suppress the occurrence of powdery mildew disease in field wheat and greenhouse melons.

Example Ί: The indoor bioassay and field control test of the derivative compound 2 (ω-hydroxyemodin) of the invention against Rhizoctonia solani

Rhizoctonia solani AG ₅ (predominant hyphae fusion group of Hubei Province) was used for indoor bioassay. It was first activated on a PDA (potato glucose agar medium) for 72 hours, and then derivative compound 2 was first diluted by a 2-fold concentration gradient dilution method. Set the concentration of 20000ug / ml-7.8125 ug / ml of the drug (10 times the concentration of each treatment), and then dissolve the PDA, mix the drug solution with the PDA culture medium 1: 9 (v / v) and make 200ug / ml ~ 0.78125 ug / ml of medicated medium, process 4 plates (diameter 9cm) each, after cooling, insert 6mm bacteria cake in the center of the plate, incubate at 25 ± 1 ° C, and allow the blank control bacteria cake to grow to At the edge of the plate, the vernier caliper cross method was used to measure the colony diameter of each treatment, and the bacteriostatic rate of each treatment was calculated. Bacteriostatic rate% = (blank colony diameter-treated colony diameter) / (blank colony diameter-colony cake diameter) x 100, and calculated EC _{5 ()} value and EC ₉₅ value. The 5% emulsion of Example 5 was used in the field and started to be applied after the tillering period of rice, with an interval of 10 days and 3 times in total. Investigation was conducted after the Rhizoctonia solani was typed. The results show that the derived compound 2 can effectively inhibit the occurrence of rice sheath blight in rice fields.

Example 8: Laboratory bioassay and field control test of cotton fusarium fungus 3 (ω-hydroxyemodin-8-methyl ether) derived from the present invention

The same method as in Example 7 was used to perform indoor bioassay and field control tests on Fusarium oxysporiwn f.sp.vasinfectum. Fusarium oxysporum f. Sp. Field control was started 10 days after transplanting cotton seedlings, once every 10 days for a total of 3 times. It was proved that compound 3 can effectively control the development of cotton blight. Cotton archaea Fvsarium oxysporium f.sp.vasinfectum treatment

EC ₅₀ ug / g EC ₉₅ ug / g

5% ω-hydroxy rhubarb 500 81.7

51.23 109.81

-8-methyl ether emulsion 800 65.2 Example 9 · Indoor bioassay and field control test of sclerotinia sclerotiorum spp.

Using the same method as in Example 7, indoor bioassay and field control tests were performed on Sclerotinia sclerotiorum. Sclerotinia sclerotiorum was first activated for 72 hours and then tested. Field control was applied in the early flowering period of rapeseed, once every 7 days and 3 times in total. It was confirmed that the derived compound 5 can effectively control the occurrence of rape sclerotinia.

Example 10: Indoor bioassay and field control test of Rhizoctonia solani on the derivative compound 8 (emodin-6-ether) of the present invention

In the same way as in Experimental Example 7, Rhizoctonia solani was tested in laboratory and in the field. The tomato was tested for 72 hours after activation. Field control started once every 7 days after seedlings were unearthed for a total of 2 times, which proved that compound 8 can effectively control the development of tomato blight.

Example 11: Indoor bioassay and field control test of the derivative compound 9 (Xanthorin-5-methylether) of the present invention on pepper anthracnose

The same method as in Example 7 was used to conduct indoor bioassay and field control tests on the pepper anthracnose Golletotrichum cflj ^ 'c. After 120 hours of activation, the pepper anthracnose was bioassayed. In the field control, the first drug was applied, and the conidia at a concentration of 10 ⁶ / ml was taken in after 24 hours, and moisturized for 3 days. On the 7th day, the disease spots on the fruits were investigated and compared with the control to calculate the control effect. It was proved that the derivative compound 9 can effectively prevent and cure pepper anthracnose.

Example 12: The indoor bioassay and field control test of the derivative compound 4 (emodin-8-methyl ether) of the present invention against Nicotiana tabacum Using spore germination bioassay method, first Ahernaria alternata Alternaria fungus activated PDA plates 4 days, and then rinsed with sterile water conidia containing glucose, diluted to ¹⁰⁶ spores / ml standby, Compound 4 It is formulated as 400ug / ml-3.125ug / ml series concentration, and then mixed with 1: 1 conidia solution in equal volume, and then 40ul is placed on a concave glass with a pipette, and the culture is maintained at 25-28 ° C for 16h. , Microscopic examination of conidia germination rate, calculation of conidia inhibition rate, conversion of conidia inhibition rate to probability value, linear regression of probability value and concentration logarithm, to obtain EC ₅₀ value and EC ₉₅ value. After the tobacco field in the rosette stage, the first agent is administered 24 hours after the inoculation concentration of 10 ⁵ / ml solution of the spores, and moisture for 3-4 days. The investigation results show that the derived compound 4 can effectively control tobacco scab.

Example 13: Bioassay and field control effects of the derivative compound 6 (cassiarin) of the present invention on Verticillium dahliae of cotton The Vertici Uiwn cotton was first activated on potato agar medium (PDA) for 120 hours. After spores were produced, the bioassay was performed in the same manner as in Example 12. In the field, the application of the pesticide was started 10 days after the cotton seedlings were transplanted, once every 10 days, and a total of 3 times, which can effectively control the occurrence of cotton verticillium wilt.

Example 14: The derivatized compound 1 (emodin-6, 8-dimethyl ether) of the present invention has a bioassay and a field control effect on cucumber gray mold fungus.

First, Botrytis cinerea was activated on the PDA for 96 hours on the PDA, and then spore production was induced by UV light for 48 hours, and then the bioassay was performed in the same manner as in Example 12. First appeared in the field when administered to 4-5 true leaves of cucumber seedlings agent after 24 hours, the access concentration of 10 ⁵ / ml spore, moisturizing 48h, the findings show that the derivative compound can effectively control gray mold.

Example 15: Combination of Derivative Compound 7 (Emodin-1, 6-dimethyl ether) of the present invention with Derivative Compound 10 (blunt leaf) of the present invention to control rice blast in the field

Derivative compound Ί and derivative compound 10 were used in a 4: 1 weight ratio to control rice blast Pyricularia grisea. The test proved that the combined preparation can effectively control the occurrence of rice blast, which is better than the control agent rice blast spirit (East Sichuan Pesticide factory).

Example 16: Combination of Derivative Compound 7 (emodin-1, 6-dimethyl ether) and Derivative Compound 6 (cassiarin) of the present invention in preventing and controlling powdery mildew in greenhouse

The weight ratio of Derivative Compound 7 and Derivative Compound 6 was 4: 1, and the disease was controlled in Shangdian in June when the disease was first seen in the greenhouse. It was applied once every 7 days for a total of 3 times, which proved that the composition can effectively control powdery mildew powdery mildew. occur.

Gardenia powdery mildew

Erysiphe cucurbitacearum & Sphaerortheca processing

cucurbitae

Application multiple Average field control effect

5% emodin methyl ether + Cassia 1000 1000

Wettable powder 2000 87.5

Claims

Claim

1. The application of anthraquinone derivatives as pesticides for controlling plant diseases, which is characterized in that the anthraquinone derivatives contain any one or more of the following anthraquinone-derived compounds:

Its chemical structural formula is:

2. The application of the anthraquinone derivative according to claim 1 as a pesticide for controlling plant diseases, characterized in that the anthraquinone derivative is used for controlling various food crops, cash crops, vegetables, fruit trees, melons, etc. Diseases caused by fungi, including: Sphaerotheca spp., Erysiphe spp., Bhimeria spp., Farium spp., Sc / erat "iJ !,

Plant diseases caused by Colletotrichum botrytis βο & γ ^, Verticilhum, Alternaria / temar ^ fungi.

3. Application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that the anthraquinone derivative compound is used to control wheat powdery mildew, melons powdery mildew, cucumber gray mold , Pesticides against rice blast, rice sheath blight, cotton fusarium wilt, cotton verticillium wilt, rape sclerotinia, tomato blight, pepper anthracnose, tobacco red spot disease.

4. Application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that when the anthraquinone derivative compound is an antifungal pesticide with an active ingredient, an agriculturally acceptable Carriers, surfactants and other auxiliary agents can be made into various carriers such as solid-phase, liquid-phase, emulsifying and dispersing agents commonly used in pesticides known in the technical field. And various dosage forms, including wettable powders, emulsifiable concentrates, microemulsions, aqueous formulations, suspensions, and water-dispersible granules.

^5. The application of anthraquinone derivatives according to claim 4 as pesticides for controlling plant diseases, characterized in that each of the anthraquinone derivative compounds can be used alone or in combination, and the proportion of the active ingredients in each pesticide preparation is by weight Counted as 5-90%.

6. The use of anthraquinone derivatives according to claim 1 or 2 as pesticides for controlling plant diseases, characterized in that said emodin-6, 8-dimethyl ether (compound 1), emodin-1, 6 — Dimethyl ether (compound 7) or Xaiithorin_5 monomethylether (compound 9) is used as a pesticide to control cucumber powdery mildew, wheat powdery mildew, and rice blast.

7. The use of anthraquinone derivatives according to claim 1 or 2 as pesticides for controlling plant diseases, characterized in that said Xanthorin-5-methylether is used as a pesticide for controlling anthracnose of pepper.

8. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, which is characterized in that the combination of emodin-1, 6-dimethylether and blunt leaf is used as a pesticide for controlling rice blast in the field .

9. The use of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that ω-hydroxyemodin-8-methyl ether is used as a pesticide for controlling cotton fusarium wilt.

10. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that the combination of emodin-1, 6-dimethyl ether and cassia is used as a pesticide for controlling powdery mildew in greenhouse. .

11. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that said 2-acetylemodin is used as a pesticide for controlling rape sclerotinia.

12. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that said emodin-6,8-dimethyl ether is used as a pesticide for controlling gray mold of cucumber.

13. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that the ω-hydroxyemodin is used as a pesticide for controlling rice sheath blight.

14. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that the Co-hydroxyemodin-8-methyl ether is used as a pesticide for controlling cotton fusarium wilt.

15. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that said emodin-8-methyl ether is used as a pesticide for controlling tobacco spot disease.

16. The application of the anthraquinone derivative according to claim 1 or 2 as a pesticide for controlling plant diseases, characterized in that said Cassia is used as a pesticide for controlling cotton verticillium wilt.