Method for preventing and controlling peanut soil pests

Abstract

This invention belongs to the field of green pest control technology in agriculture, and provides a method for controlling underground pests in peanuts: before crop sowing, previously planted Cnidium monnieri is pressed into the soil as green foliage; the sowing rate of Cnidium monnieri is 1-6.5 kg per mu, and the amount of green foliage returned to the soil is 7000-37500 kg / ha fresh weight, with the green foliage pressing occurring 5-10 days before crop sowing. The preferred underground pests are grubs, wireworms, and cutworms. This invention regulates the soil ecological environment through agronomic measures, which can increase the enrichment level of Metarhizium anisopliae in the soil and repel grubs, thereby reducing the occurrence of underground pests and mitigating yield losses caused by them. This method does not require the application of additional chemical agents specifically for underground pests and has good ecological and application value.

Description

Technical Field

[0001] This invention belongs to the field of green control technology for agricultural pests, specifically involving a method for controlling pests by using Cnidium monnieri as a green mulch to regulate Metarhizium anisopliae in the soil and repel underground pests, and particularly a method for controlling underground pests of peanuts. Background Technology

[0002] The information disclosed in this background section is intended to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Underground pests are a significant group of pests affecting underground-fruiting or underground-forming economic crops such as peanuts. They mainly include grubs, wireworms, and cutworms. These pests live in the soil for extended periods, exhibiting strong concealment, making monitoring difficult, and resulting in delayed detection of damage. They primarily feed on roots, pegs, and pods, causing missing seedlings, damaged pods, and reduced yields, potentially leading to substantial economic losses. Current control methods mainly rely on seed treatment, furrow or hole application of granular pesticides, soil treatment, and agronomical measures such as tillage and crop rotation. However, these methods generally suffer from difficulties in determining the optimal timing for control, the efficacy of pesticides being greatly affected by soil conditions, unstable residual effects, and increased pesticide residues and ecological risks.

[0004] Metarhizium anisopliae is a common entomopathogenic fungus in soil, possessing good potential for biological control of underground pests such as grubs and wireworms, and is one of the important biocontrol resources for green control of underground pests. However, current technologies for utilizing Metarhizium anisopliae mainly rely on direct application of inoculants. Its colonization, propagation, and sustained pest control effects in farmland are easily affected by factors such as soil organic matter, microbial community structure, temperature and humidity conditions, and cultivation management methods, resulting in poor stability of application effects. Currently, there is a lack of a method to regulate the soil ecological environment through agronomic measures, promote the enrichment of Metarhizium anisopliae in the soil, and simultaneously control underground pests. Summary of the Invention

[0005] To address the shortcomings of existing technologies in controlling underground pests, which primarily rely on chemical agents and lack sufficient ecological regulation methods, as well as the absence of methods to promote the accumulation of Metarhizium anisopliae in the soil and simultaneously control underground pests through agronomic measures, this invention provides a method for controlling underground pests by using Cnidium monnieri as green manure to regulate Metarhizium anisopliae in the soil and repel grubs. This method involves returning Cnidium monnieri to the field as green manure before crop sowing, which not only increases the accumulation level of Metarhizium anisopliae in the soil but also repels grubs, thereby achieving integrated control of underground pests.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for regulating soil metamorphic bacteria and repelling underground pests by using Cnidium monnieri as a green cover includes the following steps: before crop sowing, Cnidium monnieri planted in the previous period is returned to the field as a green cover to regulate the enrichment level of metamorphic bacteria in the soil and to repel underground pests.

[0008] Preferably, the sowing rate of Cnidium monnieri is 1 to 6.5 kg per mu.

[0009] Preferably, the amount of *Cnidium monnieri* used for green composting and returning to the field is 7,000–37,500 kg / ha of fresh weight.

[0010] Preferably, the greening period is 5 to 10 days before crop sowing.

[0011] Preferably, the green manure application is carried out by rotary tillage, with the soil depth reaching 15-20 cm. Multiple rotary tillage operations can be performed to ensure thorough mixing of the Cnidium monnieri with the soil. If necessary, irrigation can be carried out after green manure application, depending on soil moisture conditions, to promote the decomposition of the Cnidium monnieri.

[0012] Preferably, the crop is peanut.

[0013] Preferably, the underground pests are selected from grubs, wireworms, and cutworms.

[0014] Preferably, peanuts are sown when the soil temperature at a depth of 5 cm has remained stable above 18℃ for 5 consecutive days, with a sowing density of approximately 130,000 holes / hm², and 1 to 2 seeds sown per hole.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention can regulate the composition of soil microbial community and promote the enrichment of Metarhizium anisopliae by returning Cnidium monnieri to the field; (2) This invention can reduce the population density of underground pests, especially grubs, in peanut fields; (3) In this invention, the soil treated with green manure has a repellent effect on grubs of different ages; (4) This invention can reduce yield loss caused by underground pests and increase peanut yield; (5) This invention belongs to the green control technology that combines agronomic measures with soil biological regulation, which can reduce the dependence on chemical agents for underground pests.

[0016] Furthermore, by improving the soil ecological environment, this invention not only facilitates the enrichment of existing Metarhizium anisopliae in the soil but also provides a favorable soil environment for the colonization and reproduction of exogenous Metarhizium anisopliae. This statement is used to illustrate the applicability potential of the method of this invention but does not constitute a necessary condition for the implementation of this invention through exogenous inoculation with Metarhizium anisopliae. This point is a reasonable extension based on the technical principle of improving the soil ecological environment using the method of this invention. Attached Figure Description

[0017] Figure 1 Figure showing the changes in the relative abundance of Metarhizium anisopliae in the soil at different growth stages of peanut under different treatments of Cnidium monnieri greening amount; Figure 2 A graph showing the density of grubs and their relative abundance with Metarhizium anisopliae under different treatments; Figure 3 A graph showing the linear relationship between peanut yield and grub density under different treatments; Figure 4 Graphs showing the behavioral effects of grubs under different indoor treatments; Figure 5 This graph shows the changes in Metarhizium anisopliae content in soil under different treatments at different sampling periods during an indoor experiment. Figure 6 A graph showing the trend of Metarhizium anisopliae content in soil under different treatments at different sampling periods in an indoor experiment; Figure 7 A graph showing the dynamic changes in the number of first-instar larvae under different treatments at different sampling periods; Figure 8 A graph showing the dynamic changes in the number of second-instar larvae under different treatments at different sampling periods; Figure 9 A graph showing the dynamic changes in the number of third-instar larvae under different treatments at different sampling periods. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments and accompanying drawings, but the present invention is not limited to the following embodiments.

[0019] Example 1: Effects of Cnidium monnieri as green mulch on underground pests and the abundance of Metarhizium anisopliae in peanut fields. Field trials were conducted in late September to early October 2024 at the Shandong Peanut Research Institute Experimental Station in Laixi City, Qingdao, Shandong Province. Cnidium monnieri seeds were mixed with fine sand at a 1:1 mass ratio before sowing. The mixed seeds were evenly broadcast onto the prepared land, with seed rates of 2.3 jin (low), 7.5 jin (medium), and 12.5 jin (high) per mu (approximately 0.067 hectares). After sowing, the soil was lightly rake and covered, and irrigation was immediately carried out. Watering was repeated twice within 14 days to maintain soil moisture and promote germination.

[0020] Cnidium monnieri was allowed to grow naturally, and then applied as green mulch to the field one week before peanut planting the following year. Three treatments with varying green mulch amounts were established, corresponding to the planting rate: low, medium, and high, with green mulch amounts of 7000 kg / ha fresh weight, 22500 kg / ha fresh weight, and 37500 kg / ha fresh weight, respectively. A control group (CK) was also included without green mulch application. A rotary tiller was used to incorporate the Cnidium monnieri into the soil to a depth of 20 cm, with multiple tillages to ensure thorough mixing. Base fertilizer was applied after green mulch and before peanut planting. Peanuts were planted from late April to early May, with 85 cm wide rows, two rows per row, 16 cm spacing between plants, and two seeds per plant. Mulch was used for covering with plastic film and drip irrigation under the film. All other agricultural operations were the same for all treatments.

[0021] Soil samples were collected before greening, during the seedling stage, pegging stage, and pod-filling stage. An "S"-shaped sampling method was used to collect samples from each plot, and the samples were mixed and brought back to the laboratory at low temperature for preservation and soil microbiological analysis. ITS1-5F region amplification was performed on the soil samples, and the relative abundance of *Metarhizium anisopliae* was calculated. The results showed that the relative abundance of *Metarhizium anisopliae* in the soil of each treatment exhibited dynamic changes with the peanut growth process, with the high-green ...

[0022] The population density of underground pests was investigated at peanut harvest. The results showed that the underground pest densities under the Max, Med, and Min treatments were all lower than those under the control (CK) treatment, at 0.45 pests / m², 1.10 pests / m², 0.78 pests / m², and 2.13 pests / m², respectively. Specifically, the Max treatment showed a highly significant difference from the CK; the Min treatment showed a significant difference from the CK; and the Med treatment did not show a significant difference from the CK, but was lower than the CK.

[0023] Regression analysis of the relative abundance of *Metarhizium anisopliae* during the pegging and maturity stages with the density of grubs at harvest showed a negative correlation between the two, suggesting that *Metarhizium anisopliae* may be involved in the inhibitory effect of the method of this invention on underground pests. Since not all correlations reached a significant level, this embodiment positions *Metarhizium anisopliae* as a soil biological response related to pest control, rather than describing it as the sole mechanism of action.

[0024] Peanut yields were measured across different treatments, revealing variations. The high-pressure green layer treatment resulted in significantly higher peanut yields than the control. Insect population density showed a negative correlation with peanut yield, indicating that reducing underground pest infestations helps mitigate peanut yield losses.

[0025] This demonstrates that applying Cnidium monnieri as green mulch can regulate the enrichment level of Metarhizium anisopliae in the soil and reduce the occurrence of underground pests, thereby controlling peanut underground pests and ultimately mitigating yield losses caused by them.

[0026] Example 2: Effects of Cnidium monnieri on soil covering with green soil on grub behavior After weighing the snake bed seedlings according to different green compressing amounts, they were mechanically crushed into 0.5-1 cm pieces, and then mixed evenly with sieved soil and allowed to decompose for 10 days. Three green compressing amounts (low, medium, and high) were set up, as in Example 1, and a control soil was also set up.

[0027] A dual-zone selection device was constructed using a transparent acrylic box, dividing the box into a soil zone for the greening treatment and a control soil zone. Equal amounts of sieved soil corresponding to the treatment were filled into each zone, and an equal number of similarly sized potato granules were placed in the center as a food source. Ten larvae of the same age of the dark-browed scarab beetle were placed in each treatment, with three replicates for each age group. Observations were conducted for 3–4 days to record the distribution and changes of the grubs in different zones.

[0028] The results showed that, under the same living conditions such as soil temperature and humidity and sufficient food sources, first-instar, second-instar, and third-instar larvae of the dark-brown scarab beetle under different greening treatments were all more likely to move toward the control soil. This indicates that the greening treatment soil has a significant repellent effect on grubs, and the high greening amount treatment has a more significant repellent effect on grubs of different instars.

[0029] Meanwhile, the content of *Metarhizium anisopliae* in the soil at different sampling periods during the indoor experimental treatment was measured. The results showed that the content of *Metarhizium anisopliae* changed with treatment and time. This result indicates that the *Cnidium monnieri* greening treatment can alter the soil biological environment. Combined with the results of grub behavior, it can be seen that the method of this invention can exert a comprehensive inhibitory effect on underground pests through changes in the soil ecological environment. The repellency effect is the effect directly demonstrated in this embodiment, and the change in *Metarhizium anisopliae* is a related soil biological response.

[0030] Those skilled in the art will understand that any modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the spirit and essence of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for controlling soil metamorphic bacteria and repelling underground pests by using Cnidium monnieri as a green sap suppressant, characterized in that, Includes the following steps: Before sowing crops, the previously planted Cnidium monnieri is pressed back into the field to regulate the enrichment level of Metarhizium anisopliae in the soil and to repel underground pests.

2. The prevention and control method according to claim 1, characterized in that, The sowing rate of Cnidium monnieri is 1-6.5 kg per mu.

3. The prevention and control method according to claim 1, characterized in that, The amount of *Cnidium monnieri* that is returned to the field as green foliage is 7,000–37,500 kg / ha of fresh weight.

4. The prevention and control method according to claim 1, characterized in that, The greening period is 5 to 10 days before crop sowing.

5. The prevention and control method according to claim 1, characterized in that, The green manure is returned to the field by rotary tillage, with the soil being turned in to a depth of 15–20 cm.

6. The prevention and control method according to claim 1, characterized in that, The crop in question is peanut.

7. The prevention and control method according to claim 1 or 6, characterized in that, The underground pests were selected from grubs, wireworms, and cutworms.

8. The prevention and control method according to claim 6, characterized in that, Peanuts should be sown when the soil temperature at a depth of 5 cm has remained stable above 18℃ for 5 consecutive days. The sowing density is approximately 130,000 holes / hm², with 1 to 2 seeds sown per hole.

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