A biological control method for Canada goldenrod

Abstract

The present invention discloses a method for biological control of Canada goldenrod, relating to the field of biological control technology. A biological agent is prepared using Sclerotium delphinium SD1 and sprayed onto the stem sections of Canada goldenrod stalks. The present invention achieves a higher efficiency in controlling root rot and necrosis of Canada goldenrod than that achieved with Sclerotium truncatum, and the effect is more stable. The liquid Sclerotium delphinium agent formulated in the present invention can be efficiently sprayed in the field using a high-pressure sprayer, effectively causing root rot and necrosis of Canada goldenrod. The method overcomes the limitation of the traditional method of using Sclerotium truncatum SC64 solid herbicide granules, which requires tilling the soil before application. The present method has a wider range of applicability and is applicable to nearly all terrain and habitat types.

Description

Technical Field

[0001] The invention relates to the technical field of biological control, and in particular to a method for biological control of Canada goldenrod. Background Art

[0002] Canada goldenrod (Solidago canadensis L.), a perennial herb in the Asteraceae family, is native to North America. It has successfully invaded central and western Europe, much of Asia, Australia, and New Zealand, becoming a worldwide invasive weed. Introduced to my country in 1935 as an ornamental plant, it escaped from its native habitat, where it was plagued by numerous natural pests and diseases that prevented its spread, allowing it to spread excessively and become a malignant weed. It has become one of the most damaging invasive alien plants today and is listed on the National List of Key Managed Invasive Alien Species. It has now spread to over 10 provinces in my country, posing a significant threat to biodiversity and potentially leading to the local extinction of native species. More importantly, the invasion of Canada goldenrod has caused direct economic losses to my country's agriculture, forestry, and animal husbandry. It can also invade farmland and surrounding areas, dramatically reducing crop yield and quality. The economic losses caused by Canada goldenrod in orchards range from 10% to 30%, and in severe cases, even total crop failure. Currently, the primary control methods for Canada goldenrod are physical eradication and chemical control. Canada goldenrod reproduces sexually and asexually through seeds and rhizomes, making it extremely resilient. Furthermore, after invading my country, Canada goldenrod underwent chromosome doubling, induced by climate change, resulting in strong environmental adaptability and resistance. Consequently, physical control methods such as manual removal or uprooting, mechanical mowing, and chemical control are ineffective, as they fail to damage the root rhizomes and allow them to quickly regenerate. Furthermore, physical control is labor-intensive, while chemical control can damage the soil ecosystem and threaten biodiversity.

[0003] Chemical herbicides have developed rapidly in the 20th century due to their advantages such as affordability, quick effect, ease of use, and labor-saving. They have also brought about tremendous changes in agricultural production and human life. However, even so, the harm they bring is also enormous. Due to the unscientific use of a large number of highly toxic and high-residue chemical herbicides, irreparable damage has been caused to the environment on which humans depend for survival. Even glyphosate, a herbicide that has always been considered safe and environmentally friendly, has gradually shown problems with its impact on human health and its effectiveness. Other adverse effects include: (1) Chemical herbicide residues in the soil are difficult to degrade, affecting the growth of the next crop and the quality of agricultural products; (2) Residues in the soil are easily absorbed by crops, causing toxins to accumulate in the human body through the enrichment of the food chain from plants to humans, increasing the probability of zoonotic diseases; (3) Soil clods become compacted, water quality deteriorates, and soil fertility is reduced; (4) Adverse effects are caused on local biological communities, affecting biodiversity; (5) Increased pesticide resistance in weeds; (6) Impacts on crop photosynthesis and metabolism. Therefore, the key to solving these problems lies in the search for broad-spectrum, highly effective, low-toxic, and environmentally friendly green herbicides that are sustainable and sustainable. New, environmentally friendly bioherbicides offer an important approach. However, bioherbicide R&D faces numerous limitations, such as climate and environmental factors, particularly humidity, and production and application technology. Therefore, developing new application technologies is a crucial step in promoting the development and industrialization of bioherbicides.

[0004] Developing biocontrol agents from naturally occurring pathogenic microorganisms of invasive weeds to reduce the adverse effects of agricultural production is considered an important alternative to reducing the use of chemicals. Due to the rich diversity and complexity of pathogenic fungal microorganisms and the diversity of their metabolic pathways, microorganisms provide a rich and colorful biological resource for the development of modern agriculture and green production. Bioherbicides have the advantages of being harmless to natural enemy insects, highly selective for target weeds, not prone to developing resistance, safe for humans and animals, and having a minimal impact on the ecosystem. Field trials using a bacterial agent developed using the Sclerotium delphinium sclerotium (SD1) strain, combined with mechanical mowing, have shown that it can cause necrosis of the entire root of Canada goldenrod, achieving the goal of highly effective control. In addition, it has been reported that Junkekuo, developed using the strain Sclerotium rolfsii SC64, can effectively control Canada goldenrod when applied in combination with tillage. The limitation of this method is that the above-ground straw needs to be cut first and the root soil needs to be mechanically tilled, which has higher labor costs. In addition, most of the habitats invaded by Canada goldenrod do not have the conditions for tillage. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a method for biological control of Canada goldenrod.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for biologically controlling Canada goldenrod includes preparing a biological agent using Sclerotium delphinium SD1, and spraying the biological agent onto the stem section of Canada goldenrod straw.

[0008] As a preferred embodiment of the present invention, the application amount of the biological agent is 6000-8000 ml / mu.

[0009] As a preferred embodiment of the present invention, the Sclerotium delphinii SD1 is classified and named Sclerotium delphinii, and was deposited in the General Microbiology Center of the China Culture Collection Administration on December 28, 2023, with the deposit number: CGMCC No.41076.

[0010] As a preferred embodiment of the present invention, the gene sequence of the Delphinium sclerotium SD1 is shown as SEQ ID NO.1.

[0011] As a preferred embodiment of the present invention, the preparation method of the biological agent is as follows:

[0012] S1: Inoculate Sclerotium delphinium SD1 onto PDA medium and culture in an incubator for 4-6 days. Obtain a cake from the edge of a vigorously growing colony. Place the cake in PDB liquid medium and culture on a shaker at 30-32°C and 200-210 rpm for 3-5 days. Once a pellet is formed, grind the pellet to prepare a uniform mycelial suspension.

[0013] S2: Add 10-15 ml of Tween 80 to every 1 L of mycelial suspension to prepare a stable Delphinium microsclerotium inoculum.

[0014] As a preferred embodiment of the present invention, the PDA culture medium comprises the following raw materials in parts by weight: 200-220 parts of potatoes, 20-25 parts of glucose, 15-20 parts of agar, and 1000 parts of distilled water. The medium is sterilized at 115-120° C. for 20-25 minutes and then cooled.

[0015] As a preferred embodiment of the present invention, the PDB culture medium comprises the following raw materials in parts by weight: 300-315 parts of potato and 20-25 parts of glucose per liter of culture medium, dissolved in water to 1000 parts, sterilized under high pressure at 121°C for 20-25 minutes, and cooled to 50-55°C.

[0016] As a preferred embodiment of the present invention, the spraying is carried out during or before the flowering period of Solidago canadensis.

[0017] As a preferred embodiment of the present invention, the spraying is carried out using a high-pressure sprayer.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention uses Sclerotium delphinium as a biological agent, which makes the efficiency of controlling root rot and necrosis of Canada goldenrod higher than that of using Sclerotium truncatum, and the effect is stable.

[0020] (2) The liquid form of the Sclerotium delphinium herbicide formulated in the present invention can be efficiently sprayed in the field using a high-pressure sprayer, effectively causing root rot and necrosis of Canada goldenrod. This overcomes the limitation of the traditional method of using Sclerotium SC64 solid herbicide granules, which requires the soil to be plowed before application. The present method has a wider range of applicability and is applicable to almost all terrain and habitat types.

[0021] (3) The present invention realizes the preparation of Delphinium sclerotium SD1 mycelial suspension using PDB liquid culture medium and the addition of adjuvant Tween 80 to prepare the biological herbicide Delphinium sclerotium agent, which significantly improves the control effect, greatly shortens the production time, improves the production efficiency, and lays the foundation for mass production.

[0022] (4) The bacterial agent prepared with the highly effective Delphinium microsclerotium as the main component adopted in the present invention can be directly sprayed on the wound of the stem section after mowing the Canada goldenrod stalks to achieve excellent control effect, eliminating the need to plow the habitat soil, reducing cost investment and greatly increasing the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The growth performance of Canada goldenrod under different treatments;

[0024] Figure 2 The manifestations of root necrosis of Canadawort with different treatments;

[0025] Figure 3 is the number of regenerated seedlings of Solidago canadensis under different treatments, where A, B, and C represent the significant differences between treatments at the P < 0.01 level;

[0026] Figure 4 The regeneration of Canada goldenrod with different treatments at different times;

[0027] Figure 5 Root characteristics of Canada solidago under different control treatments. DETAILED DESCRIPTION

[0028] The following embodiments of the present invention are described in detail. The embodiments described below are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this field or the product specifications are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be obtained commercially.

[0029] Sclerotium delphinii (SD1) is a pathogenic fungus strain discovered and isolated from diseased plants of Canada goldenrod found in nature. It is currently deposited at the General Microbiology Center of the China Culture Collection Administration of Microorganisms (CGMCC, address: No. 3, Yard 1, Beichen Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code 100101), with a deposit date of December 28, 2023, and a deposit number of CGMCC No. 41076. The gene sequence is shown in SEQ ID NO. 1.

[0030] A method for biologically controlling Canada goldenrod is disclosed, comprising mowing Canada goldenrod stalks with a lightweight lawn mower, and then spraying a bacterial agent containing Sclerotium delphinium as a main component onto the stalk sections. The preparation process of the bacterial agent used in the following examples is as follows:

[0031] S1: Preparation of mycelial suspension: Inoculate Sclerotium delphinium SD1 onto PDA medium and incubate in an incubator at 30°C for 4 days. Use a 5 mm diameter borer to punch out a cake from the edge of a vigorously growing colony. Place this cake in PDB liquid medium and incubate in a shaker at 30°C, 200 rpm, for 3 days. Once pellets form, grind them to create a uniform mycelial suspension.

[0032] S2: Preparation of inoculum: Add 10 ml of Tween 80 to every 1 L of mycelial suspension to prepare a stable inoculum of Sclerotium delphinium.

[0033] S3: The weight components of the above-mentioned PDA culture medium are: 200 grams of potatoes, 20 grams of glucose, 15 grams of agar, and 1000 milliliters of distilled water. After sterilization at 115°C for 20-25 minutes, cool and set aside.

[0034] S4: The weight composition of the above-mentioned PDB culture medium is as follows: 300 g of potato and 20 g of glucose per liter of culture medium, dissolved in water to 1 L, sterilized by high pressure at 121°C for 20 min, and cooled to about 50°C for use.

[0035] S5: The spray device is a new type of electric sprayer for pesticide spraying, including an electric pressure pump, a double-hole nozzle, a spray control switch, and a connecting rod.

[0036] The control work is carried out during the flowering period of Canada goldenrod and before the flowering period. The application amount of the biological herbicide is 6000-8000 ml / mu, and obvious effects can be seen after 10-15 days.

[0037] Example 1

[0038] Comparison of the control effects of Sclerotium delphinium and Sclerotium truncatum on Canada goldenrod;

[0039] In order to compare the control effect of Sclerotium delphinium and Sclerotium sclerotium on the roots of Canada goldenrod, a pot experiment was used (two roots were placed in each pot). Roots under normal growth conditions were collected from the wild (the aboveground straw was cut off), brought back to the laboratory, and planted in nutrient pots. Three treatments were set up, namely, spraying Sclerotium delphinium on the stem section (SD1), spraying Sclerotium sclerotium sclerotium (SR1), and a control treatment (CK) of spraying PDB liquid culture medium. Each pot was sprayed with 2 ml of the agent. Each treatment had 10 replicates (pots) and was treated for 20 days. The control effect was observed after 20 days. The results are as follows: Figure 1 、 2 shown.

[0040] from Figure 1 and 2 It can be seen that the mortality rate of the Delphinium sclerotium agent SD1 on the roots of Canada thistle reached 90%, which was significantly higher than that of the Sclerotium truncatum agent SR1 (mortality rate 65%).

[0041] The roots of the four treatments were dug out, and the results showed that the rot and necrosis rate of the Canada thistle roots treated with the Delphinium sclerotium agent SD1 was significantly higher than that treated with the Sclerotium sclerotium agent SR1.

[0042] In summary, the control effect of Delphinium sclerotium SD1 is significantly better than that of Sclerotium uniformis.

[0043] Example 2 Field control demonstration effect of Delphinium microsclerotium SD1 bacterial agent

[0044] In June before flowering, a field control demonstration test of the Delphinium SD1 bacterial agent formulated by the present invention was carried out in a typical Canada goldenrod invasion area in Honggutan District, Nanchang City (invasion for more than 3 years, invasion density of more than 80 plants / square meter). The demonstration test set up four treatments, namely, spraying Delphinium SD1 bacterial agent after mowing the aboveground straw (8000ml / mu), spraying 20% amiloride (2000ml / mu) (the chemical control method with the best control effect, used as a positive control here), mowing the aboveground straw only, and control treatment. Each treatment had 3 replicate plots, each plot was 67 square meters, and observations were made every 15 days after treatment. After 60 days, the roots were dug up to observe the control effect. The anti-imitation, number of regenerated new seedlings and photo observation effects of each treatment were examined. The results are shown in Table 1 and Figure 3-Figure 5 shown.

[0045] Table 1 Control effect of each treatment on the corrected plants of Solidago canadensis

[0046]

[0047] Figure 3 The results showed that the growth of Delphinium microspores was severely inhibited after treatment with the microbial agent, and the control efficiency of the corrected strain was significantly higher than that of the mowing treatment, but did not reach a significant level with the chemical treatment (i.e., the control efficiency was very close to that of the chemical treatment) (as shown in Table 1). The number of rhizome regeneration seedlings was significantly lower than that of the mowing treatment, and there was a trend of decrease over time ( Figure 4 After 60 days of treatment, the root necrosis and regeneration of seedlings were observed. The roots of SD1 and chemical treatments were completely necrotic. The root activity of the mowing treatment was stronger than that of the CK control, and a large number of buds / seedlings were germinated ( Figure 5 In summary, the Sclerotium delphinium fungicide is highly effective in controlling Canada thistle in the field, completely killing the stubborn roots and causing a very low level of regenerated seedlings.

[0048] The above-described embodiments merely represent preferred implementations of the present invention. While the descriptions thereof are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for biological control of Solidago canadensis L., characterized in that: A biological agent was prepared using Sclerotium delphinii SD1, and the biological agent was sprayed on the stem section of Canada goldenrod straw; the Sclerotium delphinium SD1 was classified and named Sclerotium delphinii, and was deposited in the General Microbiology Center of the China Culture Collection Administration on December 28, 2023, with the deposit number: CGMCC No.41076.

2. The method for biological control of Solidago canadensis according to claim 1, characterized in that: The application amount of the biological agent is 6000-8000 ml / mu.

3. The method for biological control of Solidago canadensis according to claim 1, characterized in that: The gene sequence of the Delphinium microspore SD1 is shown in SEQ ID NO.

1.

4. The method for biological control of Solidago canadensis according to claim 1, characterized in that: The preparation method of the biological agent is as follows: S1: Inoculate Sclerotium delphinium SD1 onto PDA medium and culture in an incubator for 4-6 days. Obtain a cake from the edge of a vigorously growing colony. Place the cake in PDB liquid medium and culture on a shaker at 30-32°C and 200-210 rpm for 3-5 days. Once a pellet is formed, grind the pellet to prepare a uniform mycelial suspension. S2: Add 10-15 ml of Tween 80 to every 1 L of mycelial suspension to prepare a stable Delphinium microsclerotium inoculum.

5. The biological control method for Solidago canadensis according to claim 4, characterized in that: The PDA culture medium comprises the following raw materials in parts by weight: 200-220 parts of potatoes, 20-25 parts of glucose, 15-20 parts of agar, and 1000 parts of distilled water. The medium is sterilized at 115-120° C. for 20-25 minutes and then cooled.

6. The biological control method for Solidago canadensis according to claim 4, characterized in that: The PDB culture medium comprises the following raw materials in parts by weight: 300-315 parts of potato and 20-25 parts of glucose per liter of culture medium, which are dissolved in water to 1000 parts, sterilized under high pressure at 121° C. for 20-25 minutes, and cooled to 50-55° C.

7. The biological control method for Solidago canadensis according to claim 1, characterized in that: The spraying is specifically carried out during and before the flowering period of Solidago canadensis.

8. The biological control method for Solidago canadensis according to claim 1, characterized in that: The spraying is carried out using a high-pressure sprayer.

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