Shrub combination for storing and conserving natural enemies for farmland ecosystem and application of shrub combination

Abstract

The invention discloses a shrub combination for saving and conserving natural enemies for a farmland ecosystem and application thereof, and the shrub combination is used for providing a habitat and an overwintering and oversummering place for the natural enemies of the farmland system by planting shrubs such as rhododendron, pittosporum tobira and crape myrtle in the farmland system, so as to conserve the natural enemies and improve the ecological prevention and control effect of the natural enemies. Therefore, the natural pest control effect of a farmland ecosystem is further improved. The shrub combination provided by the invention can improve the colonization rate of natural enemies of pests in a farmland and regulate and control the predation, oviposition and other capacities of the natural enemies of the pests on crops, so that the number of the natural enemies is increased, the natural pest control effect of the natural enemies is enhanced, the population occurrence number of pests such as aphids and stem borers is reduced, and the grain yield loss caused by outbreak of pest populations is reduced; meanwhile, the shrub combination provided by the invention can also improve the biodiversity of a farmland system, reduce the use of chemical pesticides, protect the ecological environment and promote the construction of beautiful villages.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological pest control, and in particular relates to a shrub combination for storing and conserving natural enemies for a farmland ecosystem and an application thereof. Background Art

[0002] Rice, wheat, corn, and sorghum are the main grain crops, which are harmed by pests such as stem borers and aphids. Among them, rice stem borers mainly include Chilo suppressalis and Sesamia inferens, which mainly bore into rice stems with their larvae, causing rice sheaths, heart and ears to wither. Wheat aphids mainly include Sitobion avenae, Rhopalosiphum padi and Schizaphis graminum. Corn and sorghum are also harmed by Rhopalosiphum maidis, Ostriniafurnacalis and Melanaphis sacchari, respectively. Wheat aphids mainly suck the sap of wheat leaves, stems, and ears, causing yellow-white spots to appear on them. In severe cases, the entire plant can wither. Corn aphids and sorghum aphids suck plant sap as adults or nymphs, causing the leaves to turn yellow or red, affecting photosynthesis. In severe cases, they can cause baldness or even the death of the entire plant. Soybeans and rapeseed are both important oil crops in my country and occupy an important position in agricultural production. They are also harmed by pests such as aphids, resulting in reduced production.

[0003] As pests continue to cause more and more damage to crops, chemical pesticides have to be used frequently and in large quantities to increase crop yields and keep pest damage below the economic threshold. Although chemical pesticides have played a good role in controlling crop pests, the large-scale use of pesticides has caused pests to develop resistance, killed natural enemies, and destroyed ecosystem diversity, thus threatening agricultural production safety and sustainable development. Therefore, a production system that relies entirely on pesticides is unsustainable.

[0004] There are many studies on the storage and conservation of natural enemies for farmland ecosystems by functional plants. For example, there are patent documents that attract grass stink bugs by planting rapeseed in cotton fields; sesame and zinnia, nectar plants with a long flowering period, are planted around rice fields, combined with pheromones of the stem borer and biological pesticides to achieve the purpose of ecological prevention and control, and increase the biodiversity of the rice field system and reduce the use of chemical pesticides. Veronica has a significant luring effect on natural enemies such as aphid flies, and also has a certain control effect on the dominant thrips in peanut fields. However, there are few patent documents on the use of shrub combinations to store and conserve natural enemies for farmland ecosystems.

[0005] Therefore, there is an urgent need to find a shrub combination that can conserve natural enemies in the farmland ecosystem to enhance the natural pest control function of the farmland ecosystem and promote the construction of beautiful rural areas. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention provides a shrub combination for conserving natural enemies in the farmland ecosystem and its application. By planting a combination of shrubs, namely Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica in the farmland system, it provides habitats and overwintering and summering sites for natural enemies in the farmland system, conserves natural enemies, and improves the ecological control effect of natural enemies, thereby further enhancing the natural pest control function of the farmland ecosystem. At the same time, Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica used in the present invention have good ornamental properties and are the main shrub tree species for urban and rural greening, which significantly promotes the construction of beautiful rural areas.

[0007] To achieve the above objectives, the present invention is implemented by the following solutions:

[0008] On the one hand, the present invention provides a shrub combination for conserving natural enemies in the farmland ecosystem, and the shrub combination includes Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica; the shrub combination can attract and conserve natural enemies of pests.

[0009] In the prior art, there are more and more methods of using functional plants to conserve natural enemies in the farmland ecosystem. In order not to affect the normal growth of crops such as wheat, corn, and rice, the present invention uses Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica in garden applications as street trees, and plants them at intervals around the farmland and on both sides of the roads. The same species of shrubs are not adjacent to each other, forming a shrub combination composed of different tree species. By utilizing the ecological habits and characteristics of different tree species, a shrub group with a rich structure is formed, providing diverse habitats and food sources for natural enemies of pests, conserving natural enemies, and providing an efficient and environmentally friendly pest control method for the farmland ecosystem. At the same time, Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica as street trees have excellent ornamental effects, so the shrub combination not only plays a role in pest control but also beautifies the farmland environment.

[0010] Further, the pests include aphids and borers, and the natural enemies of pests include syrphid flies, ladybugs, minute pirate bugs, spiders, aphid mummies, and trichogramma wasps.

[0011] In some ways, plant shrubs Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica in the farmland crop (such as wheat, corn, sorghum, rice, soybeans, rapeseed, etc.) system to attract natural enemies of pests (syrphid flies, ladybugs, minute pirate bugs, spiders, aphid mummies, and trichogramma wasps) to prey on or parasitize pests (such as aphids, borers, spider mites, thrips, etc.).

[0012] In some ways, Photinia×fraseri is a deciduous shrub of the genus Photinia in the family Ericaceae. It blooms from April to June, with rich flower colors and a wide variety of cultivars. At maturity, the plant height is about 2 - 3 meters, mainly providing habitats and overwintering and summering sites for natural enemies such as syrphid flies, ladybugs, spiders, and parasitic wasps.

[0013] In some ways, Pittosporum tobira is an evergreen shrub of the genus Pittosporum in the family Pittosporaceae. Its flowering period is from March to May, with an umbel inflorescence at the top, and the flowers are white and fragrant. At maturity, the plant height is about 2 meters, mainly providing habitats and overwintering and summering sites for natural enemies such as syrphid flies, ladybugs, minute pirate bugs, and parasitic wasps.

[0014] In some ways, Lagerstroemia indica is a deciduous shrub plant of the genus Lagerstroemia in the family Lythraceae. The flowers are light red, purple, or white, with a panicle inflorescence at the top, and the flowering period is from June to September. At maturity, the plant height is 3 - 5 meters, mainly providing habitats and overwintering and summering sites for spiders, syrphid flies, minute pirate bugs, etc.

[0015] In some ways, the flowering periods of the three shrubs, Photinia×fraseri, Pittosporum tobira, and Lagerstroemia indica, are different, and the entire flowering period can last from March to September, ensuring that at least one shrub is in bloom during the occurrence and damage period of the main pests of crops to attract pest natural enemies. The attracted natural enemies include ladybugs, syrphid flies, minute pirate bugs, spiders, aphid mummies, trichogramma, etc. The three shrubs can all provide sustainable nectar sources, habitats, shelters, or overwintering and summering sites for pest natural enemies, promoting the growth of the natural enemy population and improving the natural pest control ability of natural enemies.

[0016] In some ways, the three shrubs, Photinia×fraseri, Pittosporum tobira, and Lagerstroemia indica, have different plant heights at maturity, and they can occupy different ecological niches in the ecosystem, facilitating the transfer and diffusion of pest natural enemies. When the crop plant height is relatively high, Lagerstroemia indica plays a major role, and when the crop plant height is relatively low or moderate, all three can play a role.

[0017] In some ways, when planting or transplanting the shrubs, ensure that the root ball is intact, dig holes at the designated points; pile fine soil around the roots, make the roots spread out, gently compact, and water thoroughly with fixed-root water in time after planting. And carry out appropriate management such as regularly thinning leaves, topping, and irrigating before flowering to ensure the good growth of the shrub plants.

[0018] In some ways, the shrubs are perennial and do not need to be planted every year, and the growth cycle of the crops coincides with the flowering period of the shrubs, which can play a better pest control role during the occurrence period of crop pests.

[0019] Furthermore, the shrubs Photinia×fraseri, Pittosporum tobira, and Lagerstroemia indica are planted at intervals along the roads on both sides of the farmland, and the same species of shrubs are not adjacent to each other.

[0020] Further, the planting spacing of the shrubs is 3 - 5 meters.

[0021] Further, the planting area of the shrubs accounts for 5 - 10% of the total crop area.

[0022] Further, the crops include any one or a combination of multiple ones among wheat, corn, sorghum, rice, soybeans, and rapeseed.

[0023] Further, regular farming operations are carried out on the shrubs, including any one of drip irrigation, watering, and pruning of the shrubs.

[0024] On the other hand, the present invention provides a farmland ecosystem, including a shrub combination, farmland crops, and natural enemies of pests. The shrub combination is as described in the above technical solution. The farmland crops include any one or a combination of multiple ones among wheat, corn, sorghum, rice, soybeans, and rapeseed. The natural enemies of pests include hoverflies, ladybugs, minute pirate bugs, spiders, aphid mummies, and trichogramma wasps.

[0025] On yet another aspect, the present invention provides a method for controlling farmland pests. The method includes planting the shrub combination as described in the above technical solution on both sides of the roads, boundary strips, or wider field ridges in the farmland crop system to provide a habitat for the natural enemies in the farmland system, so as to improve the natural pest control effect of the natural enemies.

[0026] In some ways, the shrub combination for conserving and cultivating natural enemies in the farmland ecosystem includes operations such as drip irrigation, watering, and pruning of the shrubs to achieve a more effective ecological prevention and control effect.

[0027] On yet another aspect, the present invention provides an application of a shrub combination in increasing the number of natural enemies of pests or enhancing the pest control effect of natural enemies. The shrub combination is as described in the above technical solution.

[0028] On yet another aspect, the present invention provides an application of a shrub combination in reducing the population occurrence numbers of aphids and borers. The shrub combination is as described in the above technical solution.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. By adopting the combination of the present invention, while achieving the purpose of ecological pest control, the application of chemical pesticides in the agricultural production process can be reduced, the pollution of chemical pesticides to the environment can be lowered, which is beneficial to the protection of the ecosystem.

[0031] 2. By adopting a shrub combination (rhododendron + pittosporum tobira + lagerstroemia indica) in farmlands such as wheat, corn, sorghum, rice, soybean, and rapeseed fields, the present invention realizes the pest control effect, without competing with crops for water and fertilizers, and without affecting lighting and ventilation conditions. Planting the three shrubs of rhododendron, pittosporum tobira, and lagerstroemia indica improves the biodiversity of the farmland ecosystem, plays the role of attracting natural enemies, provides nectar sources and habitats for natural enemy insects, creates an ecological environment conducive to the proliferation of natural enemy insects, and promotes the pest control effect of natural enemies on pests in the target farmland.

[0032] 3. By adopting different shrub combinations and utilizing their different flowering periods and plant height differences, the present invention ensures the maximization of the ecological prevention and control effect. The three different shrubs can all provide habitats and overwintering and summering places for pest natural enemies. In addition, the three shrubs adopted in the present invention have different plant heights, can occupy different ecological niches in the farmland to meet the needs of different farmland ecosystems, and facilitate the transfer and diffusion of pest natural enemies.

[0033] 4. By adopting the combination mode of rhododendron + pittosporum tobira + lagerstroemia indica and combining management measures such as leaf thinning, topping, and drip irrigation, the shrub plants can provide suitable hosts, prey, pollen, nectar, and over-summering or over-wintering places for pest natural enemies. During the flowering periods of the three shrubs, the types and quantities of natural enemies on them are relatively large, and the natural enemies can transfer and diffuse between the shrubs and the crop fields, improving the control effect of natural enemies on crop pests and reducing the probability of pest outbreaks.

[0034] 5. By planting the combination of shrubs rhododendron, pittosporum tobira, and lagerstroemia indica in various farmlands (such as wheat, corn, sorghum, rice, soybean, rapeseed, etc.), the growth characteristics (rhododendron and pittosporum tobira are evergreen throughout the year) and growth and development periods (different flowering periods) of the shrubs can be utilized. Especially, the characteristics that different flowering periods can attract different types of natural enemy insects and provide them with a good habitat can not only ensure that at least one shrub is in the flowering period during the period of crop pest damage, but also occupy different ecological niches in the farmland to meet the needs of different farmland ecosystems and facilitate the transfer and diffusion of natural enemies.

[0035] 6. The method of the present invention can improve the colonization rate of natural enemy insects (such as syrphid flies, ladybugs, minute pirate bugs, spiders, aphid mummies, trichogramma) in the farmland, increase the number of natural enemies, enhance the pest control effect of natural enemies, reduce the occurrence of pest populations (such as aphids, borers, spider mites, thrips, etc.), and reduce the food yield loss caused by pest population outbreaks. And the method of the present invention can also reduce the use of chemical pesticides, protect the ecological environment, and realize the safe production of crops. Detailed implementation manners

[0036] The following further describes the present invention in detail with reference to the embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention and do not limit it in any way.

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0038] Example 1: A shrub combination for storing and conserving natural enemies in farmland ecosystems

[0039] 1. Plant shrub strips along wheat fields and rice roads and borders where pest ecological control is required.

[0040] 2. Setting a planting pattern of wheat fields, rice fields and shrubs (this example uses Deqing County and Jiashan County of Zhejiang Province as test sites)

[0041] (1) Wheat planting method: dig narrow furrows (20 cm wide) every 2 meters, and sow wheat in a 2-meter-wide strip between each two furrows;

[0042] (2) Rice planting methods: There are four main methods: hand transplanting, machine transplanting, mechanical direct seeding and broadcasting.

[0043] (3) The shrubs are planted in a single row at a spacing of 3-5 meters on both sides of the road and the boundary line around the wheat field and the rice field. In this embodiment, a planting spacing of 4 meters is preferred, and the shrubs are planted in the order of azalea, pittosporum, and crape myrtle. The planting distance between the shrub combination and the wheat field and the rice field is about 3 meters.

[0044] (4) Shrub planting area accounts for 10% of the wheat and rice planting area.

[0045] 3. Planting time and specific planting methods

[0046] (1) The planting time of wheat is mid-to-late November; in double-season rice areas: early rice is generally planted in March-April, and late rice is planted in June-July; in single-season rice areas: the planting period of rice is May-June. During the growing period, normal field management, such as fertilizer and water, is carried out, but the use of chemical pesticides for pest control is minimized;

[0047] (2) The planting or transplanting time of shrubs is mid-to-late April. Water them (drip irrigation) at regular intervals to ensure their normal growth and development. Do not apply any chemical fertilizers or pesticides. Regularly thin the leaves and remove the tops of the shrubs before flowering to ensure their good growth.

[0048] 4. Experimental results investigation

[0049] The survey method used was to place a Malvern net in the field and take samples 7 days after placement. Five Malvern nets were placed in each treatment, and each Malvern net was used as a biological replicate, for a total of 5 biological replicates. The data in the table are the average values ​​of 5 biological replicates.

[0050] (1) Verification of the attracting effect of the shrub combination on natural enemies of pests

[0051] In April and May 2024 (before and after shrub planting), the occurrence of natural enemies of pests in the wheat fields at the test site in Deqing County, Zhejiang Province was investigated, as shown in Table 1.

[0052] Table 1 Statistics of natural enemies of pests in wheat fields

[0053]

[0054]

[0055] According to the survey data, it can be seen that before shrub planting, there were basically no or only a small number of natural enemies of pests (such as hoverflies and ladybugs) in the wheat fields; after shrub planting, the types and quantities of natural enemies of pests in the wheat fields increased significantly.

[0056] (2) Verification of the good role of the shrub combination in conserving and nourishing natural enemies of pests

[0057] After that, in March and April of the following year, the occurrence of natural enemies on shrubs and wheat during the wheat growth season was investigated, and the statistical results are shown in Table 2 and Table 3.

[0058] Table 2 Statistics of natural enemies of pests on shrubs and wheat in March

[0059]

[0060] Table 3 Statistics of natural enemies of pests on shrubs and wheat in April

[0061]

[0062] Combining the results of Table 2 and Table 3, it can be seen that by March, the occurrence of wheat aphids was relatively low, and the number of natural enemies on shrubs increased significantly; by April, the number of aphids on wheat increased significantly, and the natural enemies on shrubs transferred, so the number of natural enemies transferred to wheat also increased significantly.

[0063] In summary, the shrub combination of this invention: Rhododendron simsii, Pittosporum tobira, Lagerstroemia indica, has an excellent effect of attracting natural enemies of pests, can provide good nectar sources, habitats and shelters for natural enemy insects, significantly promote the increase in the number of natural enemies of pests in wheat fields; at the same time, it also has a good role in conserving and nourishing natural enemies of pests (such as hoverflies and ladybugs), which is beneficial to the rapid growth of the population of natural enemies of pests; at the same time, the shrub combination of this invention is also conducive to the transfer and diffusion of natural enemies of pests to wheat fields.

[0064] Example 2: Control effect of the shrub combination on field pests

[0065] The present invention further investigated the pest control effects in wheat fields and paddy fields at two experimental sites in Deqing County and Jiashan County, Zhejiang Province in Example 1. The number of pests in areas planted with shrub combinations and areas without shrubs was respectively counted, and the statistical data was calculated and analyzed to obtain the control effect results. Control effect % = (1 - number of pests in the area with shrubs / number of pests in the control area) × 100%. The survey results are shown in Tables 4 and 5.

[0066] Table 4 Pest control effects at the experimental site in Deqing County

[0067]

[0068] Table 5 Pest control effects at the experimental site in Jiashan County

[0069]

[0070] As can be seen from the data in Tables 4 and 5, after planting shrubs at two different experimental sites, effective control of field pests can be achieved. Compared with the areas without shrubs planted, the number of pests in the farmland after planting shrubs has decreased significantly. The control effect on rice stem borers is between 55% and 66%, and the control effect on wheat aphids is above 57%. The above results show that planting the shrub combination provided by the present invention around farmland can effectively reduce the number of field pests and achieve efficient control of field pests.

[0071] Example 3: Influence of shrub planting distance on natural enemies controlling pests

[0072] In order not to affect the normal growth of crops, the shrub combination that conserves natural enemies for the farmland ecosystem is generally planted on both sides of roads or around farmland. The distance between the shrubs and the farmland will affect the control effect of the natural enemies on the field pests by the shrubs. Therefore, the present invention also tested the control distance of the natural enemies on the shrubs on the field pests. The planting distances between the shrub combination in Example 1 and the wheat fields were set to 0 m, 5 m, 15 m, and 30 m respectively, and the other planting methods and planting times were the same as those in Example 1. Then, the number of natural enemies on the shrubs under different planting distance conditions was respectively counted and the control effect on wheat aphids was calculated. Control effect % = (1 - number of pests in the area with shrubs / number of pests in the control area) × 100%. The statistical results and pest control effects are shown in Table 5.

[0073] Table 6 Influence of different planting distances of the shrub combination on the number of natural enemies and control effects

[0074]

[0075] As shown in the data in Table 6, as the planting distance increases, the number of natural enemies on the shrubs decreases, and the pest control effect declines. Within the planting range of 0 - 5m, the number of natural enemies such as syrphid flies, ladybugs, aphid mummies, and spiders remains at a relatively high level, and the pest control effect can reach over 60%; within the planting range of 15 - 30m, the number of natural enemies such as syrphid flies, aphid mummies, and ichneumon wasps decreases, but the shrubs within this distance can still achieve a pest control effect of over 50%. At the same time, the present invention adopts the same planting setting for paddy fields and counts the control effect of rice stem borers. The results show that it is similar to the control effect of wheat aphids, indicating that when the planting distance between the shrub combination provided by the present invention and the wheat field is within the range of 0 - 30m, a pest control effect of over 50% on field pests can be achieved, and within the planting distance of 0 - 5m, the control effect can reach over 60%.

[0076] Example 4: Evaluation of the attraction of pest natural enemies by single or two - tree - species shrub combinations

[0077] In order to further explore whether the use of single - tree - species shrubs or two - tree - species shrub combinations can achieve the same effect as the three - tree - species shrub combination in attracting pest natural enemies, the present invention also compared the planting methods of using only one type of shrub or a combination of two types of shrubs. Other planting patterns and time are basically the same as those in Example 1. Then, the occurrence of pest natural enemies on the shrubs after different combinations of shrubs were planted was investigated. The control effect%=(1 - the number of pests in the area with shrubs / the number of pests in the control area)×100%. Table 7 shows the data on the number of pest natural enemies and the control effect of wheat aphids. The control effect results of rice stem borers are consistent with the trend of wheat aphids.

[0078] Table 7 Statistics of the number of natural enemies and control effect of different shrub combinations

[0079]

[0080] According to the experimental data, it is found that the control effect of planting one tree species on stem borers and aphids can reach 20% - 25%, and the control effect of planting two tree species on aphids and stem borers can reach 38%. The shrub combination of three tree species can achieve a pest control effect of more than 66%. As shown in the data in Table 7, by comparing the seven planting methods, it can be seen that when planting shrubs with one, two, or three tree species, there is no obvious difference in the attraction of the three pest natural enemies, ladybugs, spiders, and Orius sauteri. However, the number of the three natural enemies attracted by the shrub combination of Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica is slightly higher than that of other combinations. It is speculated that the reason may be that ladybugs, spiders, and Orius sauteri have a wide adaptability to the habitat environment and can inhabit and reproduce under various tree species conditions. However, the habitat environment composed of the three shrubs is more complex and can meet the needs of different natural enemies. This speculation can be further verified from the statistical data of Sphaerophoria scripta, Aphidius gifuensis, and Ichneumonidae. The number of natural enemies attracted by the shrub combination of three tree species is significantly higher than that of a single tree species or a combination of two tree species. The reason is that the three different tree species, Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica, are planted at intervals and the same tree species are not adjacent to each other. Moreover, the three shrubs are different in terms of tree height, flowering period, etc. Therefore, the interaction between the three shrubs forms a more complex and stable structure, providing diverse habitats and food sources for different types of pest natural enemies. Therefore, compared with other combinations, the number of attracted natural enemies increases significantly, and the pest control effect is also significantly improved.

[0081] By comparing groups ① - ③ and ⑦, it can be found that when choosing a single tree species as a shrub for planting, the number of attracted natural enemies is extremely small or almost none, and the highest control effect on wheat aphids can reach about 25%. The reason is that a single tree species can create a limited living environment and food source for natural enemies. Therefore, only some types of natural enemies can be attracted. At the same time, the living space formed by one shrub is limited, which also causes it to be unable to meet the growth and reproduction of a large number of natural enemies, so the number is low. By comparing groups ④ - ⑦, it can also be seen that the shrub combination of two tree species can increase the number of attracted natural enemies, and the pest control effect can reach 30% - 38%. However, the effect is still not as good as that of the combination of three shrubs, indicating that the ecological structure composed of two shrubs can meet the living needs of different natural enemies to a certain extent, but the growth space or food source it provides is still limited. Therefore, the shrub combination of Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica (combination ⑦) can significantly improve this defect and enhance the attraction ability of the shrub combination to natural enemies. The number of attracted natural enemies is significantly higher than that of combinations ① - ⑥, achieving a control effect of more than 66% on field pests, indicating that Rhododendron simsii, Pittosporum tobira, and Lagerstroemia indica have a significant synergistic effect in attracting pest natural enemies.

[0082] Example 5: Evaluation of the attraction of shrub combinations of different tree species to pest natural enemies

[0083] Shrub species that can conserve natural enemies in farmland ecosystems need to have a long flowering period on the one hand, so as to provide continuous nectar and pollen for attracting natural enemies of pests. On the other hand, the branch and leaf structure of the tree species should be convenient for insects to reproduce and inhabit. There are many shrubs that meet the above conditions, such as Lagerstroemia indica, Ligustrum lucidum, Ilex chinensis, etc. In order to explore the differences in the effects of different combinations of shrub tree species in attracting natural enemies of pests, the present invention selects six shrubs, namely Lagerstroemia indica, Ligustrum vicaryi, Hibiscus syriacus, Rhododendron simsii, and Pittosporum tobira, for arbitrary combination. Combination 1: Lagerstroemia indica, Rhododendron simsii, Pittosporum tobira; Combination 2: Lagerstroemia indica, Ligustrum vicaryi, Hibiscus syriacus; Combination 3: Ligustrum vicaryi, Rhododendron simsii, Pittosporum tobira; Combination 4: Lagerstroemia indica, Hibiscus syriacus, Rhododendron simsii, Pittosporum tobira.

[0084] The planting pattern, time, method, etc. are basically the same as in Example 1. The occurrence of natural enemies of pests on shrubs after different combinations of shrubs were planted was investigated respectively. Control effect % = (1 - number of pests in the area with shrubs / number of pests in the control area) × 100%. The statistical results and pest control effects are shown in Table 8.

[0085] Table 8 Situation of different combinations of shrubs attracting natural enemies of pests and pest control effects

[0086]

[0087]

[0088] According to the statistical data in Table 8, it can be seen that the number of natural enemies that can be attracted by the shrub combinations of Combination 2 or Combination 3 is significantly lower than that of Combination 1. Among them, the differences in the numbers of spiders, aphid mummies, and ichneumon wasps are the most obvious. At the same time, the control effect on field pests can only reach 35.6% - 46.8%. The reason may be that in the shrubs composed of Lagerstroemia indica, Ligustrum vicaryi, and Hibiscus syriacus (Combination 2), although all three plants can provide nectar and food sources for natural enemies of pests, the plant heights of Lagerstroemia indica and Hibiscus syriacus are relatively high, which is easy to attract parasitic wasps such as aphid mummies and ichneumon wasps that prefer tall shrubs to inhabit. However, the number of hoverflies, ladybugs, and spiders attracted by Ligustrum vicaryi is limited. After the combination of the three plants, there is no synergistic effect on different types of natural enemies, so the number of natural enemies attracted is limited. For the shrub combination composed of Ligustrum vicaryi, Rhododendron simsii, and Pittosporum tobira (Combination 3), the number of aphid mummies and ichneumon wasps that can be attracted is even less than that of Combinations 1 and 2. There is also a certain gap in the numbers of hoverflies, ladybugs, and spiders between it and Combination 1. The reason is that Ligustrum vicaryi, Rhododendron simsii, and Pittosporum tobira all belong to low shrubs, which do not meet the inhabiting conditions of aphid mummies and ichneumon wasps. At the same time, the food sources that the three shrubs can provide for hoverflies, ladybugs, and spiders are also limited. Therefore, the overall number of natural enemies attracted decreases, and the control effect on pests is relatively low.

[0089] By comparing Combination 1 and Combination 4, it can be found that the shrub combination of Lagerstroemia indica, Hibiscus syriacus, Rhododendron simsii and Pittosporum tobira (Combination 4) can also attract a large number of natural enemies of pests. However, the overall quantity is still lower than that of the shrub combination of Lagerstroemia indica, Rhododendron simsii and Pittosporum tobira. Moreover, the control effects on stem borers and aphids can only reach about 50% - 56%. This may be because the four tree species compete for light, water and nutrients with each other, resulting in restricted growth of each tree species, thus reducing the food and habitats available for natural enemies. At the same time, the shrub combination composed of two medium and high shrubs (Lagerstroemia indica, Hibiscus syriacus) and two low shrubs (Rhododendron simsii, Pittosporum tobira) increases the management difficulty, and improper pruning or maintenance may damage the habitat environment of natural enemies. In summary, only the shrub combination of Rhododendron simsii, Pittosporum tobira and Lagerstroemia indica can effectively attract natural enemies of pests, achieve a control effect of over 60% on different types of pests, and is beneficial to plant growth and field management.

[0090] Although the present invention has been disclosed above in its preferred embodiments, it is not intended to limit the present invention. Any person familiar with this technology can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A shrub combination for storing and conserving natural enemies in a farmland ecosystem, characterized in that, The shrub combination includes the following shrubs: Rhododendron, Pittosporum tobira, Lagerstroemia indica; the shrub combination can attract and conserve natural enemies of pests.

2. The shrub combination according to claim 1, wherein, The shrubs Rhododendron, Pittosporum tobira, and Lagerstroemia indica are planted at intervals in turn on both sides of the roads around the farmland, and the same kind of shrubs are not adjacent to each other.

3. The shrub combination according to claim 2, characterized in that, The planting spacing of the shrubs is 3 - 5 meters.

4. The shrub combination according to claim 3, wherein The planting area of the shrubs accounts for 5 - 10% of the total area of the crops.

5. The shrub combination according to claim 4, characterized in that, The crops include any one or a combination of multiple ones among wheat, corn, sorghum, rice, soybeans, and rapeseed.

6. The shrub combination according to claim 5, characterized in that, Regular agricultural operations are carried out on the shrubs, including any one of drip irrigation, watering, and pruning of the shrubs.

7. An agricultural ecosystem, characterized in that, It includes a shrub combination, farmland crops, and natural enemies of pests. The shrub combination is as described in any one of claims 1 to 6. The farmland crops include any one or a combination of multiple ones among wheat, corn, sorghum, rice, soybeans, and rapeseed. The natural enemies of pests include Syrphidae, ladybugs, Orius minutus, spiders, Aphidiidae, and Trichogramma.

8. A method for controlling pests in farmland, characterized in that, The method includes planting the shrub combination as described in any one of claims 1 to 6 on both sides of the roads, boundary strips, or ridges in the farmland crop system to provide a habitat for natural enemies in the farmland system.

9. Use of a shrub combination in increasing the number of natural enemies of pests or enhancing the pest control effect of natural enemies, characterized in that, The shrub combination is as described in any one of claims 1 to 6.

10. Use of a shrub combination in reducing the population occurrence numbers of aphids and borers, characterized in that, The shrub combination is as described in any one of claims 1 to 6.

Images