Bemisia tabaci luring method and application thereof

Abstract

The invention belongs to the field of plant protection, and discloses a method for inducing bemisia tabaci by a persicaria orientalis volatile matter and a related application of the persicaria orientalis volatile matter to the bemisia tabaci. A Y-type olfactometer behavior experiment shows that the bemisia tabaci has a remarkable chemotactic reaction on the red-knees herb, and the preference of the bemisia tabaci is obviously higher than that of a common host tomato. Furthermore, solid phase microextraction (SPME) is combined with gas chromatography-mass spectrometry (GC-MS) to analyze the smell components of the polygonum hydropiper, and various volatile substances possibly participating in chemotaxis are screened out. The method can be used for developing a plant source smell attractant and improving the pest monitoring and green prevention and control efficiency.

Description

Technical Field

[0001] This invention belongs to the field of plant protection, specifically relating to methods for attracting whiteflies and their applications, and more specifically to the application of volatile substances from Polygonum tinctorium in the field of attracting agricultural pests. Background Technology

[0002] The tobacco whitefly (Bemisiatabaci), belonging to the order Hemiptera and family Aleyrodidae, is a global agricultural pest that seriously damages various crops. Conventional chemical control methods easily lead to the accumulation of resistance and environmental pollution. In recent years, the "ecological attraction-monitoring" strategy based on pest behavior regulation has received widespread attention, especially the method of using plant volatiles as natural attractants. However, known plant-derived attractants are mostly concentrated in crops such as tomatoes and cotton, and their attraction effects are significantly affected by the environment and variety. Finding new high-quality attractant plants and analyzing their volatile substances is one of the important directions of current green pest control technologies.

[0003] Yellow sticky traps are currently the main technology for controlling whiteflies, based on their attraction to yellow. Whiteflies rely on sight and smell to find host plants, which is why yellow sticky traps are effective at killing them. However, in practical applications, whether in open fields or greenhouses, plants often grow densely, severely hindering the whiteflies' visual perception, resulting in a limited attraction range for the yellow sticky traps and making it difficult to achieve the desired control effect. Therefore, the effectiveness of existing technologies in practical applications is limited.

[0004] Li Shu et al.'s study on "Behavioral Responses of MED Whitefly to Volatile Substances from 13 Plants" (Chinese Journal of Plant Protection, 2016, 43(1): 105-110) showed that linalool, trans-2-hexenal, and eucalyptol were significantly attractive to both male and female adults of the MED whitefly species, while cymene, myrcene, 3-picrine, α-pinene, and cis-3-hexen-1-ol exhibited varying degrees of repulsive effects. However, the release concentrations of these volatile substances are significantly variable, influenced by factors such as plant variety, health status, and damage state, leading to insufficient stability of the research results in practical applications. Therefore, there is an urgent need to develop a stable whitefly pheromone control method that performs well in the field. Summary of the Invention

[0005] This invention marks the first discovery that *Polygonum hydropiper* possesses a strong chemotactic attraction to whiteflies. Behavioral assays revealed that, compared to tomatoes, whiteflies exhibited a significantly higher selectivity for *Polygonum hydropiper* odor in a Y-type olfactory spectrometer, demonstrating a high degree of preference. Further SPME-GC-MS analysis of the volatile odor components of *Polygonum hydropiper* detected various terpenoids and alcohols, including β-caryophyllene, α-pinene, and (E)-β-caryophyllene. These results provide theoretical support and a chemical basis for developing plant-derived attractants based on the odor of *Polygonum hydropiper*.

[0006] The volatile substances emitted by Polygonum chinense are the attractant components of the whitefly pheromone. This substance is composed of multiple components, including a complex of isosorbide dimethyl ether, isooctane, and decyl acrylate carbonate. This mixture was screened based on the biological characteristics of the whitefly pest and the types and characteristics of its tactic stimuli. It has a specific attraction effect on the whitefly pest and can attract adult whiteflies to gather.

[0007] Therefore, the present invention provides a whitefly control product comprising an attractant prepared from Polygonum hydropiper or its volatile extract, and an attractant carrier; specifically, the carrier is selected from at least one of: sticky traps (such as yellow sticky traps), funnel traps or insect suction devices.

[0008] The attractant is impregnated in a slow-release carrier, preferably a lure made of porous sponge or fiberboard; more specifically, the attractant is in liquid form and loaded onto a blank lure.

[0009] Preferably, the attractant is an ethanol extract of Polygonum hydropiper, comprising a combination of two active ingredients: irisone and decyl acrylate carbonate.

[0010] The attractant is prepared by dissolving the active ingredient in a solvent and mixing them by shaking; the preferred solvents include dichloromethane, dimethyl sulfoxide, and isopropyl ketone.

[0011] Meanwhile, the present invention also provides a method for attracting or controlling whiteflies, wherein the whitefly control product is used to attract whiteflies.

[0012] The method described therein is further used to attract whiteflies in fields, greenhouses, or hothouses.

[0013] The method is further used to attract whiteflies in areas where the following crops are grown: Solanaceae crops, such as tomato (Solanum lycopersicum), eggplant (S. melongena), pepper (Capsicum annuum), and tobacco (Nicotiana tabacum); Fabaceae, Brassicaceae, Poaceae, Cucurbitaceae, Asteraceae, and Malvaceae crops such as cotton (Gossypium spp.).

[0014] The method described herein can be further used in conjunction with a yellow board.

[0015] The present invention also provides a method for planting crops, wherein red knotweed is planted around, in the middle of or interspersed with crops damaged by whiteflies.

[0016] The present invention also provides the use of Polygonum hydropiper or its volatile extracts in attracting whiteflies.

[0017] The application is preferably used in field monitoring of whiteflies, identification of migration trends, or in the development of green trapping devices.

[0018] In the aforementioned application, preferably, the volatile extract is an ethanol extract of Polygonum tinctorium, which includes a combination of two active ingredients: senna ketone and decyl acrylate carbonate.

[0019] The volatile extract is prepared by dissolving the active ingredient in a solvent and mixing by shaking; preferred solvents include dichloromethane, dimethyl sulfoxide, and isopropyl ketone.

[0020] This invention provides a method for attracting whiteflies using red knotweed as the attractant plant, which is applicable to field monitoring of whiteflies, identification of migration trends, and development of green trapping and control devices.

[0021] The attractant described in this invention can also be called a pheromone attractant.

[0022] In some embodiments, the pheromone attractant consists of senna ketone and a solvent.

[0023] In some embodiments, the pheromone attractant consists of isooctane and a solvent.

[0024] In some embodiments, the pheromone attractant consists of decyl acrylate carbonate and a solvent.

[0025] In some embodiments, the pheromone attractant of the present invention does not contain other active ingredients, yet it can effectively attract whiteflies.

[0026] This invention relates to the application of a composition of isoshyobunone, decyl prop-1-en-2-yl ester, and octane as a pheromone attractant for whiteflies (Bemisiatabaci).

[0027] Experiments show that the attractant activity of acetamiprid, decyl acrylate carbonate, and isooctane against whiteflies decreases sequentially when used alone. However, when acetamiprid, decyl acrylate carbonate, and isooctane are combined, the trapping efficiency is significantly and synergistically enhanced. In some implementation schemes, the combination of only two active ingredients, acetamiprid and decyl acrylate carbonate, can effectively reverse the repulsive behavior of whiteflies, achieving a substantial enhancement in trapping efficacy.

[0028] According to the present invention, the pheromone attractant is applicable to a variety of crops damaged by whiteflies, including but not limited to:

[0029] • Solanaceae crops: Tomato (Solanum lycopersicum), Eggplant (S. melongena), Chili pepper (Capsicum annuum), Tobacco (Nicotiana tabacum)

[0030] · Fabaceae, Brassicaceae, Poaceae

[0031] • Crops belonging to the Cucurbitaceae, Asteraceae, and Malvaceae families, such as cotton (Gossypium spp.).

[0032] In practice, the pheromone attractant works by impregnating a slow-release carrier, preferably a decoy core made of porous sponge or fiberboard.

[0033] The liquid pheromone attractant of this invention can be loaded onto blank lures to achieve highly efficient attraction of adult male and female whiteflies. This technical solution can be used in conjunction with yellow sticky traps, significantly improving the integrated control efficiency of whiteflies through a dual mechanism of "pheromone-guided targeting + physical adhesion and killing".

[0034] In some embodiments, the pheromone attractant is prepared by dissolving the active ingredients (acorine and decyl acrylate carbonate) in a solvent and then mixing them by shaking. Preferred solvents include dichloromethane, dimethyl sulfoxide, and isopropanone, which have high solubility for acorine and can ensure uniform loading of the active ingredients in the carrier, thereby significantly improving the volatilization and release efficiency of the attractant.

[0035] Specifically, the solvent system excludes paraffin and acetone to avoid crystallization of active ingredients or degradation of bioactivity.

[0036] The present invention also relates to a method for controlling whiteflies in fields / greenhouses, comprising: deploying the control product in the target area, and dynamically adjusting the product application amount according to crop density, insect population, and facility space.

[0037] The beneficial effects of the invention are as follows:

[0038] This invention represents a breakthrough discovery: the compound of acetamiprid and decyl acrylate carbonate exhibits a strong attraction effect on whiteflies, and a supporting technical formula has been established. Precise formulation: By optimizing the solvent system (excluding paraffin / acetone), the active ingredients are stably dissolved, ensuring effective concentrations in the field. Convenient application: Solvent-impregnated slow-release attractants (sponge / fiberboard) simplify the operation process. Dual-mechanism synergy: When used in conjunction with physical trapping devices (yellow sticky traps, etc.), a highly efficient control system of "chemical information guidance + physical adhesion and extermination" is formed. Broad-spectrum adaptability: It has a strong attraction to both male and female adults, with a residual effect of ≥30 days (controlled release by the slow-release carrier), unaffected by temperature and humidity fluctuations. Zero pesticide residue, meeting green control standards. Attached Figure Description

[0039] Figure 1 A schematic diagram of a selective experiment on plants such as red knotweed and tomato by whiteflies.

[0040] Figure 2 Y-tube diagram illustrating the selective effect of whiteflies on plant volatiles.

[0041] Figure 3 The selection rate of whiteflies on plants such as red knotweed and tomatoes.

[0042] Figure 4 A selective study of the volatile substances of the main red knotweed by whiteflies.

[0043] Figure 5 Yellow sticky traps in the field increase the attraction rate of volatile substances to whiteflies. Detailed Implementation

[0044] The present invention will be described below through specific embodiments in order to better understand the present invention, but this does not constitute a limitation on the present invention.

[0045] [Example 1] Test of Red Polygonum multiflorum attracting whiteflies

[0046] Preliminary experiment: Plants of uniform growth and free from pests and diseases, including *Persicaria orientalis*, tomato (*Solanum lycopersicum*), or cotton (*Gossypium spp.*), were placed diagonally opposite sides of a nylon cage (80cm x 60cm x 50cm). One hundred randomly selected male and female adult whiteflies (*Bemisia tabaci*, type Q) were placed in the cage, and their chemotactic selection behavior was observed over 24 hours. The results showed that most of them chose *Persicaria orientalis* as their host plant. Figure 1 ).

[0047] Y-shaped olfactometer experiment: Odor source chambers on both sides of the Y-shaped olfactometer ( Figure 2 An equal number of plants (one plant, approximately 25 cm tall) were placed on each side. Twenty-five adult whiteflies (male and female) were injected into the central tube, and their chemotactic behavior was observed over 5 minutes. The experiment was conducted at 25 ± 1°C, 60% RH, and a light intensity of 2000 lux. Each treatment was repeated three times, with the insect source changed each time.

[0048] Experimental results showed that, on average, 76% of whiteflies chose the direction of the scent of red knotweed over tomatoes and red knotweed, which was higher than the 22% that chose tomatoes (t-test, P < 0.001); and 95% of whiteflies chose the direction of the scent of red knotweed over cotton, which was much higher than the 5% that chose cotton (t-test, P < 0.001), indicating that the scent of red knotweed has a significant attraction effect on whiteflies. Figure 3 ).

[0049]

Example 2

[0050] Six-week-old Polygonum hydropiper plants were selected, and volatile matter was collected from them between 9:00 and 11:00 AM. The entire plant, excluding the roots (approximately 300 g), was placed in a sealed 5000 mL glass container, and a solid-phase microextraction fiber (SPME, 50 / 30 μm DVB / CAR / PDMS) was inserted. Extraction was performed at room temperature for 30 minutes. Immediately after collection, the sample was inserted into the GC-MS inlet (250°C) for analysis.

[0051] Gas chromatography-mass spectrometry (GC-MS) conditions: Agilent 7890B / 5977A system, DB-5MS capillary column (30 m × 0.25 mm × 0.25 μm), temperature program: 40°C for 2 min, ramp to 250°C at a rate of 5°C / min, total run time 45 min. Mass spectrometry range: m / z 35–500. Component identification was performed using the NIST spectral library.

[0052] The main volatile components detected included isoshyobunone, decyl prop-1-en-2-yl ester (Carbonic acid), and octane (2,4,6-trimethyl-). Characteristic odors of tomatoes and cotton were excluded from the database. Trimethylcyclohexanol acetate had the largest area (approximately 65%) and was considered one of the main behavioral active ingredients (Table 1).

[0053] Table 1: Major volatile components detected

[0054]

[0055] [Example 3] Experiment with Free Choice of Different Volatile Compounds

[0056] Based on the analysis results of odor compounds from TYLCV-infected and healthy tomato plants using solid-phase microextraction, a free-selection apparatus was used to conduct a tropism experiment on different odor compounds in whiteflies. For example... Figure 2 As shown, among the 11 odor substances, three whitefly-attracting odor substances were found: succinate, decyl acrylate carbonate, and isooctane. Figure 4 The results showed that these three odor substances have good application value in attracting whiteflies.

[0057] [Example 4] Application Test of Field Trapping Device

[0058] 30g of fresh Polygonum multiflorum leaves were frozen in liquid nitrogen, ground, and then extracted with 20mL of cooled ethanol. The extract was dispensed into 2.0mL centrifuge tubes and centrifuged at 4℃ and 12000rpm using a refrigerated centrifuge to extract key volatile substances. Odor lures (using activated carbon as a carrier to adsorb the concentrated solution) were then prepared and installed on yellow sticky traps. One set of these traps (treatment group) was placed every 10 meters in the tomato field. Blank lures and yellow sticky traps served as the control group. The trapping period was 3 days, with the lures replaced daily and the number of whiteflies attracted counted.

[0059] The results showed that the treatment group attracted an average of 75-82 whiteflies, while the control group attracted only 28-35. The attraction rate of whiteflies in the treatment group was 2.6 times that of the control group (P < 0.01). The attraction effect was stable and not significantly affected by wind direction or temperature. This device has the advantages of simple construction, low cost, significant attraction effect, and easy use.

Claims

1. A product for controlling whiteflies, characterized in that, An attractant comprising a plant of Polygonum tinctorium or its volatile extract, and an attractant carrier; specifically, the carrier is selected from at least one of a sticky trap (such as a yellow sticky trap), a funnel trap, or a suction device.

2. The whitefly control product as described in claim 1, characterized in that, The attractant is impregnated in a slow-release carrier, preferably a lure made of porous sponge or fiberboard; more specifically, the attractant is in liquid form and loaded onto a blank lure.

3. The whitefly control product as described in claim 1, characterized in that, The attractant is an ethanol extract of Polygonum hydropiper, which includes a combination of two active ingredients: senna ketone and decyl acrylate carbonate. The attractant is prepared by dissolving the active ingredient in a solvent and mixing them by shaking; the preferred solvents include dichloromethane, dimethyl sulfoxide, and isopropyl ketone.

4. A method for attracting or controlling whiteflies, characterized in that: The tobacco whitefly control product as described in any one of claims 1 to 3 is used to attract tobacco whiteflies; Preferably, it is used to attract whiteflies in fields, greenhouses, or hothouses.

5. The method as described in claim 4, characterized in that: It is used to attract whiteflies in the following crop growing areas: Solanaceae crops, such as tomatoes ( Solanum lycopersicum ),eggplant( S. melongena ),chili( Capsicum annuum ),tobacco( Nicotiana tabacum Crops belonging to the Fabaceae, Brassicaceae, Poaceae, Cucurbitaceae, Asteraceae, and Malvaceae families, such as cotton, Gossypium spp. ).

6. The method as described in any one of claims 4 or 5, characterized in that: Further use in conjunction with yellow board.

7. A method for planting crops, characterized in that, Plant red knotweed around, in the middle of, or in a cross pattern with crops that are infested by whiteflies.

8. Application of Polygonum hydropiper or its volatile extracts in attracting whiteflies.

9. The application as described in claim 8, characterized in that, Its applications include field monitoring of whiteflies, identification of migration trends, and development of green trapping devices.

10. The application as described in claim 8, characterized in that, The volatile extract is an ethanol extract of Polygonum tinctorium, which includes a combination of two active ingredients: senna ketone and decyl acrylate carbonate. The volatile extract is prepared by dissolving the active ingredient in a solvent and mixing by shaking; preferred solvents include dichloromethane, dimethyl sulfoxide, and isopropyl ketone.

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