Application of aescin in preparation of fruit fly insect antifeedant

Abstract

The invention discloses an application of aescin in preparation of a fruit fly insect antifeedant. The invention proposes that the natural plant medicine aescin can be used as the insect antifeedant for the first time, and verification shows that the aescin has a remarkable antifeedant effect on adult and larva of bactrocera dorsalis, can be used as the antifeedant for the fruit fly pests, is further developed into a natural medicine for preventing and controlling the fruit fly pests, and has a wide application prospect. The composition is nontoxic and nuisanceless to various crops, vegetables, melons and fruits and other commercial crops, does not generate drug resistance of chemical drugs, does not pollute the environment or harm human health, and has a very good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of natural medicines and pesticides, and particularly relates to application of aescin in preparing a fruit fly insect antifeedant. Background Art

[0002] Fruit flies are a type of insect belonging to the family Tephritidae in the order Diptera. There are many species of fruit flies. Their larvae are all lurking predators, harming all parts of plants, from roots, stems, leaves, flowers to fruits. Many species are crop pests, among which the fruit flies of the genus Bactrocera are particularly important. Fruit flies have a tail needle at the end of their tails, which is the ovipositor. The adult fruit flies lay eggs and pierce into fruits and melons. The hatched larvae eat the flesh of fruits and melons, causing the fruits and melons to turn yellow in some parts, and then the whole fruit and melon (fruit) rots and becomes smelly, causing a large number of fruits and melons to fall off. Even if they do not rot, the wounds are condensed with gum, and the fruit and melon (fruit) are deformed and sunken. The skin of the fruit and melon (fruit) is hard and firm, and the fruit and melon (fruit) taste bitter, which seriously affects the quality and yield of the fruit and melon (fruit). Several fruit fly species that have been discovered in China include important pests that harm citrus, pears, melons and other fruits and vegetables, such as the citrus fruit fly, the citrus fruit fly, the melon fruit fly and the wolfberry fruit fly. Fruit flies have a very strong reproductive capacity and are migratory, so chemical control is difficult to achieve the desired effect.

[0003] Bactroceradorsalis Hendel is an important pest of citrus crops, widely distributed in tropical and subtropical regions around the world, and poses a serious threat to the production of citrus and other fruit trees. The control technology of Bactroceradorsalis Hendel has made certain progress in different regions, mainly using a variety of integrated control methods such as chemical control and biological control.

[0004] Chemical control is a traditional method for the control of orange fruit fly, mainly through spraying insecticides to control its number. Commonly used insecticides include organophosphates, pyrethroids and systemic pesticides. However, due to the increasing resistance of orange fruit fly to certain pesticides, the effectiveness of single chemical control methods is decreasing, and chemical pesticides may have a negative impact on the environment and ecosystem. Therefore, over-reliance on chemical control is not recommended.

[0005] Biological control is a control method that has gradually gained attention in recent years. It mainly involves using natural enemies of the fruit fly to control its number. Natural enemies of the fruit fly include parasitic wasps, predatory insects and pathogenic microorganisms. Parasitic wasps can parasitize the eggs or larvae of the fruit fly to achieve the effect of biological control. In addition, certain insect pathogens, such as fungi and viruses, are also used for biological control. Biological control is environmentally friendly and sustainable, and has gradually become a powerful supplement to chemical control.

[0006] In recent years, studying the regulatory effects of functional plants on insect behavior and developing insect behavior regulators have become important research directions in the field of green control of agricultural pests. Using plant-derived active ingredients to repel or inhibit the behavior of pests has gradually become an effective way to replace traditional chemical control, and has received more and more attention and application. For the prevention and control of the orange fruit fly, researchers have begun to explore the potential of plant-derived substances, using their natural repellent and inhibitory effects to reduce the damage of the orange fruit fly. Specifically, plant extracts or their active ingredients, such as volatile essential oils, phenolic compounds, etc., have been proven to effectively interfere with the phototaxis, chemotaxis and oviposition behavior of the orange fruit fly. These plant-derived substances can not only repel the adult orange fruit fly, but also inhibit its egg production and larval survival rate to a certain extent, thereby reducing the risk of pests.

[0007] By screening plant-derived substances with high activity and low toxicity, researchers have developed a series of green control products, such as plant extracts and plant essential oil sprays, for the control of Bactrocera dorsalis. These products not only have good control effects, but are also environmentally friendly and will not have a negative impact on other beneficial insects or ecosystems. Therefore, the application prospects of plant-derived substances in the control of Bactrocera dorsalis are broad, and they will become an important part of the future green agricultural control strategy.

[0008] The taste system is one of the key chemosensory systems in insects. It plays a key role in sensing the chemical composition of food through direct contact and regulating behaviors such as mating, feeding and oviposition. Among them, insect Grs involved in the recognition of sweet and bitter substances (such as plant toxic metabolites) are important for feeding decisions.

[0009] Insect repellents are specific agents that interfere with or inhibit the function of insect taste receptors, preventing them from feeding. This type of chemical generally prevents insects from feeding without directly killing them. Insect repellents can not only protect plants from being eaten by insects, but also help protect the ecological balance. Therefore, in plant protection work, insect repellents are an ideal potential insect repellent. Using them to control pests can avoid and reduce the harm of chemical pesticides to the environment and humans.

[0010] Escin is a sodium saponin extracted from the dried mature seeds of the Aesculus plant. It is a freeze-dried sterile preparation and is a natural botanical medicine with anti-inflammatory, anti-swelling, analgesic and blood circulation improving effects. It is currently mainly used as a medicine. There is no report on the use of escin to avoid and repel insects (Bactrocera dorsalis) in the prior art. Summary of the invention

[0011] The purpose of the present invention is to provide a use of aescin in the preparation of a fruit fly insect antifeedant in view of the above problems.

[0012] In order to achieve its purpose, the present invention adopts the following technical solution:

[0013] The first aspect of the present invention provides the use of aescin in insect repellent.

[0014] The second aspect of the present invention provides the use of aescin in the preparation of an insect antifeedant.

[0015] In the above-mentioned application technology solution, the insects are fruit fly insects.

[0016] Preferably, the insect is Bactrocera.

[0017] The fruit flies include the oriental fruit fly, the orange fruit fly (Tetradacus citri (Chen)), the melon fruit fly (Bactroceracucuribitae (Coquillett)), the south Asian fruit fly (Bactroceratau Walker), and the Mediterranean fruit fly (Ceratitis capitata).

[0018] In the above-mentioned application technology scheme, the working concentration of aescin is 0.1 μM and above, preferably 0.1-1000 μM or 0.1-500 μM or 0.1-200 μM or 1.0-500 μM or 1.0-100 μM.

[0019] The third aspect of the present invention provides an insect repellent, the active ingredient of which includes aescin.

[0020] The insect repellent is a fruit fly, preferably a fruit fly.

[0021] The insect antifeedant further comprises a solvent, and the solvent is selected from methanol and DMSO.

[0022] In the insect antifeedant, the concentration of aescin is 0.1 μM or above, preferably 0.1 to 1000 μM.

[0023] The beneficial effects of the present invention are as follows: it is proposed for the first time that a natural plant medicine aescin can be used as an insect antifeedant, and it has been verified that it has a significant antifeedant effect on both adults and larvae of the citrus fruit fly, can be used as an antifeedant for fruit fly pests, and can be further developed into a natural medicine for preventing and controlling fruit fly pests. It is non-toxic and pollution-free to various crops, vegetables, fruits and other economic crops, will not produce resistance to chemical drugs, will not pollute the environment and harm human health, and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the experimental setup and method for feeding selection of adult Bactrocera dorsalis.

[0025] Figure 2 This is a schematic diagram of the experimental setup and method for feeding selection of Bactrocera dorsalis larvae.

[0026] Figure 3 These are the results of the bidirectional choice behavior experiment on feeding of Bactrocera dorsalis adults.

[0027] Figure 4 These are the results of the bidirectional choice behavior experiment on feeding of Bactrocera dorsalis larvae. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereto.

[0029] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0030] Example 1, feeding selection test

[0031] 1 Materials and methods

[0032] The experimental test insects were the oriental fruit fly that had been cultured for a long time in the laboratory of this research team. The culture temperature was 27±1℃, the relative humidity was 70%±5%, and the photoperiod was 14:10 (light:dark).

[0033] The aescin (CAS No.: 6805-41-0) used in this experiment was purchased from Shanghai Yuanye Biotechnology Co., Ltd. and dissolved in methanol as a solvent to prepare solutions with concentrations of 1 μM, 10 μM, 100 μM, and 1000 μM for the experiment.

[0034] 1.1 Adult feeding selection

[0035] The adult feeding selection experiment was conducted in a transparent acrylic cage (size 25 cm × 25 cm × 25 cm). Two culture dishes with a diameter of 3 cm were placed diagonally in each cage. Each culture dish contained 10 ml of a sucrose solution with a concentration of 100 mM, and a escin solution was added to the culture dish located on the lower side (multiple treatment groups of escin solutions with different concentrations were set up, and 1 acrylic cage was 1 treatment). That is, the feed in the culture dish on the upper side was 100 mM sucrose solution, and the feed in the culture dish on the lower side was 100 mM sucrose solution + escin. Multiple treatment groups of escin solutions with different concentrations were set up, and the final concentrations of escin in the feed solution were 0.1 μM, 1 μM, 10 μM, and 100 μM, respectively.

[0036] The experimental design included 30 B. dorsalis in each treatment group, and 3 replicates were set for each treatment to ensure statistical validity. The B. dorsalis was starved for 18 hours before the experiment, and then the B. dorsalis was placed in an acrylic cage and allowed to eat for 30 minutes, and then the number of B. dorsalis in each culture dish was counted. The feeding preference index (PI) was calculated as shown in Formula I:

[0037] PI=(N 上侧 -N 下侧 ) / (N 上侧 +N 下侧 )Formula I

[0038] In formula I, N 上侧 Represents the number of Bactrocera dorsalis in the upper culture dish, N 下侧 Represents the number of Bactrocera dorsalis in the lower petri dish.

[0039] 1.2 Larvae feeding selection

[0040] The larval feeding selection experiment was conducted using a two-part dish with a diameter of 9 cm. Feed was added on both sides of the dish. The feed on the left side of the dish was artificial feed for larvae + sucrose (the final concentration in the feed was 100mM), and the feed on the right side of the dish was artificial feed for larvae + sucrose (the final concentration in the feed was 100mM) + aescin (different final concentrations were set: 0.1μM, 1μM, 10μM, 100μM respectively). The formula of artificial feed for larvae is as follows: 18g agar, 30g filter paper, 60g white sugar, 60g yeast, 75g wheat germ powder, 180g corn flour, 4.2g methyl paraben, 2.1g sorbic acid, 3g vitamin C, 1ml linoleic acid, add water to make up to 1L, and the feed is a paste.

[0041] 30 third-instar larvae were placed in the middle of each plate and placed in a dark incubator at 25°C for 30 minutes to allow them to feed. The number of larvae on each side of the plate was then counted. Three replicates were set for each treatment. The feeding preference index (PI) was calculated as shown in Formula II:

[0042] PI=(N 左侧 -N 右侧 ) / (N 左侧 +N 右侧 )Formula II

[0043] In Formula II, N 左侧 Represents the number of Bactrocera dorsalis on the left side of the plate, N 右侧 Represents the number of Bactrocera dorsalis on the right side of the plate.

[0044] 2 Results and analysis

[0045] 2.1 Adult feeding selection

[0046] In the behavior selection experiment, if aescin was not added, the fruit fly did not show obvious preference or avoidance behavior towards feeding ( Figure 3 ). However, after adding aescin to the double-choice experiment of adult feeding, when the initial concentration of aescin was 0.1 μM, the fruit fly quickly showed a clear preference for feeding on the upper culture dish without aescin, and as the concentration of aescin in the lower culture dish increased, the aversion of the fruit fly to aescin gradually increased ( Figure 3 ), and the peak preference index reached 0.596 when the aescin concentration level was 100 μM. The preference index (PI) results are shown in Table 1:

[0047] Table 1 Preference index (PI) of adult double-choice experiment

[0048]

[0049] 2.2 Larvae feeding selection

[0050] Unlike adults, larvae of Bactrocera dorsalis did not show significant preference at a escin concentration of 0.1 μM. When the escin concentration increased to about 1 μM, the larvae also began to avoid feeding, reaching a peak preference index of 0.755 (0.900 μM) at a escin concentration of 100 μM. Figure 4 ). The preference index (PI) results are shown in Table 2:

[0051] Table 2 Preference index (PI) of larvae in the double-choice experiment

[0052]

[0053] The above results show that aescin has a significant antifeedant effect on both adults and larvae of Bactrocera dorsalis in a dose-dependent manner.

Claims

1. Application of aescin in insect repellent.

2. Application of aescin in the preparation of insect antifeedants.

3. The use according to claim 1 or 2, characterized in that: The insects are fruit flies.

4. The use according to claim 3, characterized in that: The insect is fruit fly.

5. The use according to claim 4, characterized in that: The fruit flies include the oriental fruit fly, the citrus fruit fly, the melon fruit fly, the south Asian fruit fly, and the Mediterranean fruit fly.

6. The use according to claim 1 or 2, characterized in that: The working concentration of aescin is 0.1 μM and above, preferably 0.1-1000 μM or 0.1-500 μM or 0.1-200 μM or 1.0-500 μM or 1.0-100 μM.

7. An insect antifeedant, characterized in that: Its active ingredients include aescin.

8. The insect antifeedant according to claim 7, characterized in that: The insects are fruit flies, preferably fruit flies.

9. The insect antifeedant according to claim 7, characterized in that: The invention also comprises a solvent, and the solvent is selected from methanol and DMSO.

10. The insect antifeedant according to claim 8, characterized in that: In the insect repellent, the concentration of aescin is 0.1 μM or above, preferably 0.1 to 1000 μM.

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