Plant-derived biocontrol composition as insecticide alternative and use thereof

Abstract

The application discloses a plant source biological control composition as a pesticide substitute and application thereof; the application utilizes the induction effect of volatile oil and sex pheromone to promote a large number of plutella xylostella larvae to swallow the composition, effectively overcomes the insufficient intake dose problem caused by the taste defense of pests of a traditional antifeedant, under the synergistic effect of the alkaline environment in the intestinal tract of the pests and light, the composition is activated and active oxygen is released in the body, not only the harm of the pests to crops is rapidly terminated through physiological antifeeding, but also the proteins and chitins of the pests are degraded into free amino acids and chitooligosaccharides through biochemical reaction, while the biting of the plutella xylostella larvae to crops is avoided, the plutella xylostella larvae are induced to die and are transformed into natural fertilizer sources which can be directly absorbed by crop root systems, under the premise of ensuring low toxicity, no residue and environmental friendliness, directional material transformation from harmful organisms to crop nutrients is realized.

Description

Technical Field

[0001] This invention relates to insecticide substitute technology, and more particularly to a plant-derived biocontrol composition as an insecticide substitute and its application. Background Technology

[0002] The diamondback moth is a major global pest of cruciferous vegetables, with over 40 host species, primarily including cabbage, bok choy, cauliflower, Chinese cabbage, and rapeseed, causing particularly severe damage to cabbage and cauliflower. Early-instar larvae mainly feed on the leaf mesophyll, leaving the epidermis intact, creating "open windows" in the leaves. Third and fourth-instar larvae increase their appetite, gnawing holes and notches into the leaves; in severe cases, they can eat the entire leaf, creating a web-like pattern, significantly impacting photosynthesis and growth. They can also transmit various diseases such as soft rot during feeding, leading to reduced yield and quality. Due to its high reproductive rate, short life cycle, multiple generations, and long-distance migratory habits, the diamondback moth is extremely difficult to control.

[0003] For a long time, chemical pesticides have been the main means of controlling the diamondback moth. However, due to the long-term and large-scale use of chemical pesticides, the diamondback moth has developed varying degrees of resistance to more than 50 insecticides, including organochlorines, organophosphates, carbamates, pyrethroids, and insect growth regulators. Resistance to some pesticides has reached as high as 8000 times. The overuse of chemical pesticides has also led to a series of problems, such as killing natural enemies, polluting the environment, and exceeding pesticide residue limits, seriously threatening the quality and safety of agricultural products and the safety of the ecological environment.

[0004] Therefore, it is necessary to design a plant-derived biocontrol composition and its application as an insecticide alternative to solve the above problems. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a plant-derived biological control composition as an insecticide substitute and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a plant-derived biocontrol composition as an insecticide substitute, comprising, by weight 1000 parts:

[0007] Petroleum ether extract of *Bryum brevicornu*, 20-200 parts.

[0008] 10-100 parts of ethyl acetate extract of *Bryum brevicornu*

[0009] 5-50 parts of volatile oil extract from cruciferous plants.

[0010] 0.1-5 parts of crude extract of diamondback moth sex pheromone.

[0011] 10-100 parts of co-solvent, and the remainder water.

[0012] In a preferred embodiment of the present invention, the preparation of the petroleum ether phase extract of *Bryophytum brevicornu* comprises:

[0013] The dried whole herb of *Bryum shortribum* was pulverized to 20-80 mesh, and 95% ethanol at a mass-to-volume ratio of 1:5-15 was added. The mixture was refluxed at 60-80℃ for 2-4 times, each time for 1-3 hours. The extracts were combined and concentrated under reduced pressure at 40-50℃ until no alcohol odor was detected, thus obtaining the extract.

[0014] Dissolve the extract in 10-50 times its weight of water, extract with an equal volume of petroleum ether 2-4 times, combine the petroleum ether phases, and evaporate to dryness under reduced pressure at 40-50℃ to obtain the final product.

[0015] In a preferred embodiment of the present invention, the preparation of the ethyl acetate phase extract of *Bryophytum brevicornu* comprises:

[0016] The aqueous phase after petroleum ether extraction is extracted 2-4 times with an equal volume of ethyl acetate. The ethyl acetate phases are combined and evaporated to dryness under reduced pressure at 40-50℃ to obtain the final product.

[0017] In a preferred embodiment of the present invention, the photosensitivity of the extract of *Bryum brevicornu* is enhanced under pH conditions of 8.5-10.0.

[0018] In a preferred embodiment of the present invention, the cruciferous plant volatile oil extract comprises: volatile substances from cruciferous plants;

[0019] The volatile oil extract from the cruciferous plants is horseradish volatile oil extract or mustard seed volatile oil extract, which is extracted by steam distillation: the plant tissue is crushed, 2-5 times the mass of water is added, and steam distillation is carried out for 2-6 hours. The distillate is collected, and after salting out, ether extraction, drying with anhydrous sodium sulfate, the ether is evaporated to obtain the extract.

[0020] In a preferred embodiment of the present invention, the crude extract of diamondback moth sex pheromone comprises: diamondback moth sex pheromone;

[0021] The extraction of sex pheromones from the diamondback moth includes: collecting the abdominal end of female diamondback moths, soaking them in hexane for 12-24 hours, filtering, and concentrating the filtrate to dryness under a nitrogen stream to obtain a crude extract of sex pheromones.

[0022] In a preferred embodiment of the present invention, the composition further comprises a natural photosensitizing synergist selected from crude chlorophyll extract, and the amount used is 1-30 parts by weight.

[0023] In a preferred embodiment of the present invention, the composition preparation includes: mixing the petroleum ether phase extract of *Bryum brevicornu*, the ethyl acetate phase extract, the volatile oil extract of cruciferous plants, the crude extract of sex pheromones from *Plutella xylostella*, a solubilizer, a natural photosensitizing synergist, and water in a specified ratio, and stirring at 20-40°C for 10-30 minutes until uniformly dispersed.

[0024] In a preferred embodiment of the present invention, the co-solvent is one or more of propylene glycol, glycerin, Tween 80, and Span 80.

[0025] Application of a plant-derived biocontrol composition as an insecticide alternative in biocontrol agents.

[0026] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0027] (1) This invention utilizes the inducing effect of volatile oils and sex pheromones to induce diamondback moth larvae to swallow large amounts of the composition, effectively overcoming the problem of insufficient intake due to the taste defense of pests caused by traditional antifeedants. Under the synergistic effect of the alkaline environment in the insect's intestine and light, the composition is activated in the body and releases reactive oxygen species. It not only quickly terminates the harm to crops through physiological antifeeding, but also degrades the insect's proteins and chitin into free amino acids and chitosan oligosaccharides through biochemical reactions. While preventing diamondback moth larvae from eating crops, it induces the diamondback moth larvae to die and transforms them into natural fertilizer sources that can be directly absorbed by the crop roots. Under the premise of ensuring low toxicity, no residue, and environmental friendliness, it realizes the directional transformation of harmful organisms into crop nutrients.

[0028] (2) This invention utilizes the glucosinolate degradation products rich in horseradish volatile oil or mustard seed volatile oil, in conjunction with the mating chemical signals released by the sex pheromone of diamondback moth, to construct a chemical concentration gradient with olfactory deception in the microenvironment of crop canopy. This gradient can shield and cover the natural odor of the extract of short-ribbed moss, inducing the target pests to produce strong directional attraction and feeding impulse. This allows the pests to ingest a high dose of the composition before they realize the antifeedant activity, thus completely solving the concentration limitation of conventional plant-derived antifeedants, which cause pests to stop feeding after only a small amount of contact when applied to the plant surface, thus preventing the accumulation of lethal doses. This ensures that the subsequent oxidative degradation reaction has sufficient substrate and material basis.

[0029] (3) This invention utilizes the strong alkaline midgut environment unique to lepidopteran pests to perform molecular allosteric transformation and combines it with specific wavelength light for physical excitation. The macromolecules in the extract of *Bryum brevicornu* remain physically inert in the weakly acidic to neutral environment of nature. When ingested by diamondback moths and in contact with their strong alkaline intestinal fluid, the acidic functional groups undergo deprotonation allosteric transformation and are converted into photosensitive precursors. By applying specific light, photon energy penetrates the body wall to excite the allosteric molecules and transfers the energy obtained to oxygen molecules dissolved in the midgut of the insect. This results in the instantaneous generation of high concentrations of singlet oxygen and hydroxyl radicals inside the insect, achieving highly precise control over the release time and space of active ingredients and their target. Compared with the limitations of conventional plant-derived insecticides in the prior art, which are easily degraded and rendered ineffective by the natural environment after spraying and are prone to accidentally killing non-target beneficial insects, this method avoids the premature decay of efficacy caused by light interference and greatly improves the environmental safety and target specificity of the formulation in complex field ecosystems. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a line graph comparing the experimental results of Examples 1 to 7 of the present invention;

[0032] Figure 2 This is a line graph comparing the experimental results of Examples 8 to 12 of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0035] Application Overview:

[0036] Existing insecticides or plant-derived antifeedants typically employ surface contact poisoning or simple repulsion mechanisms. A physical drawback of these mechanisms is that once the pesticide adheres to the crop surface and pests initially contact and recognize the toxic or antifeedant components, they immediately cease feeding. This behavioral feedback means that the total absolute amount of active compounds ingested by the pests in their digestive tract cannot reach the lethal concentration threshold required to completely block their physiological metabolism. To address this technical problem, the present invention constructs a complex reaction chain involving targeted attraction, physical accumulation, in-situ allosteric transformation, and photocatalytic lysis.

[0037] Specifically, the volatile oil extracts from cruciferous plants and the crude extract of diamondback moth sex pheromones in the composition serve as targeted attraction modules. The antennal sensilla and mouthpart taste receptors of lepidopteran pests such as the diamondback moth exhibit extremely low recognition thresholds and extremely high binding affinity for volatile substances specific to cruciferous plants (such as degradation products of glucosinolates) and homologous sex pheromones. This technical solution utilizes the chemical signals released by these two types of substances to form a high-concentration attractant odor gradient around the composition. This odor gradient, spatially distributed, can completely cover and shield the inherent odor molecular signals of the *Bryum brevicornu* extract, thereby deceiving the chemoreceptor neurons of the target pest and inducing strong directional attraction and continuous feeding behavior. This technique directly overcomes the physical barrier preventing antifeedant agents from penetrating the pest's body, enabling the *Bryum brevicornu* extract to achieve high-concentration physical accumulation in the midgut of the pest at unconventional dosages.

[0038] A plant-derived biocontrol composition as an insecticide alternative, the composition comprising:

[0039] Petroleum ether phase extract and ethyl acetate phase extract of *Bryophytum brevicornu*;

[0040] Volatile oil extracts from cruciferous plants;

[0041] Crude extract of sex pheromones from the diamondback moth;

[0042] After the composition is ingested by pests, the photosensitive active ingredients in the extract of *Bryum brevicornu* are activated in the alkaline environment of the pest's intestines, generating reactive oxygen species under light conditions. These reactive oxygen species simultaneously induce the pests to exhibit antifeeding behavior and decompose the macromolecules in the pest's body. The decomposition products can be absorbed by crops as plant nutrients.

[0043] In this invention, the preparation of the petroleum ether phase extract of *Bryophytum brevicornu* includes:

[0044] The dried whole herb of *Bryum shortribum* was pulverized to 20-80 mesh, and 95% ethanol at a mass-to-volume ratio of 1:5-15 was added. The mixture was refluxed at 60-80℃ for 2-4 times, each time for 1-3 hours. The extracts were combined and concentrated under reduced pressure at 40-50℃ until no alcohol odor was detected, thus obtaining the extract.

[0045] Dissolve the extract in 10-50 times its weight of water, extract with an equal volume of petroleum ether 2-4 times, combine the petroleum ether phases, and evaporate to dryness under reduced pressure at 40-50℃ to obtain the final product.

[0046] Specifically, the extraction process involves pulverizing the dried whole plant of *Brucea shortribensis* to 20-80 mesh. The particle size parameter aims to disrupt the cross-linking structure of cellulose and pectin in the cell walls of bryophytes, maximizing the specific surface area of ​​the solid material. This shortens the mass transfer distance for the extraction solvent to penetrate into the cells and for the active ingredients to diffuse outward.

[0047] After pulverizing, add 95% ethanol at a mass-to-volume ratio of 1:5-15, and reflux extract at 60-80℃ 2-4 times, each time for 1-3 hours.

[0048] Choosing 95% ethanol as the primary extraction solvent utilizes its dual properties of hydroxyl and hydrocarbon groups, which enable it to broadly dissolve nonpolar, weakly polar to moderately polar secondary metabolites within the cells of *Bryum brevicornu*, such as flavonoids, polyphenols, terpenes, and large-molecule fat-soluble pigments.

[0049] Reflux at a temperature range of 60-80℃, because 60-80℃ is close to the boiling point of ethanol, can increase the kinetic energy of solvent molecules, reduce the kinetic viscosity of the extract, and accelerate the thermal motion and dissolution rate of intracellular macromolecules.

[0050] After combining the extracts, the solution was concentrated under reduced pressure at 40-50℃ until no alcohol odor remained. This vacuum distillation technique allows for rapid removal of the solvent at a lower boiling point, preventing oxidative degradation or isomerization of the thermosensitive and photosensitive active substances under prolonged high temperatures, ultimately yielding a petroleum ether extract.

[0051] The aqueous phase after petroleum ether extraction is extracted 2-4 times with an equal volume of ethyl acetate. The ethyl acetate phases are combined and evaporated to dryness under reduced pressure at 40-50℃ to obtain the final product.

[0052] Ethyl acetate has a moderate dipole moment and hydrogen bond acceptor ability, enabling it to form intermolecular interactions with moderately polar polyphenols, flavonoid aglycones, and certain alkaloids in the aqueous phase, thereby stripping them from the highly polar aqueous environment.

[0053] The ethyl acetate phases were combined and evaporated to dryness under reduced pressure at 40-50℃ to obtain the ethyl acetate extract of *Bryum brevicornu*. In the final control composition, the ethyl acetate extract and the petroleum ether extract form a chemical synergy. The polyphenols in the ethyl acetate phase can act as electron donors or reaction intermediate carriers in the subsequent photodynamic reaction, producing a synergistic effect with the photosensitizing agent in the petroleum ether phase, expanding the absorption spectrum and prolonging the excited state lifetime.

[0054] In this invention, the cruciferous plant volatile oil extract includes: volatile substances from cruciferous plants; the diamondback moth sex pheromone crude extract includes: diamondback moth sex pheromones;

[0055] The cruciferous plant volatile oil extract is horseradish volatile oil extract or mustard seed volatile oil extract, which is extracted by steam distillation: the plant tissue is crushed, 2-5 times the weight of water is added, steam distillation is carried out for 2-6 hours, the distillate is collected, and after salting out, ether extraction, drying with anhydrous sodium sulfate, the ether is evaporated to obtain the extract.

[0056] The diamondback moth, an oligophagous insect, relies heavily on finding volatile odors specific to cruciferous plants. Steam distillation was employed, utilizing steam as both a heat transfer medium and a carrier.

[0057] When the system boils, the volatile oil components inside the plant tissue vaporize along with the water vapor and enter the condenser, where they are converted into a liquid.

[0058] Adding 2-5 times the volume of water ensures that physical dry burning does not occur during distillation, while also preventing excessive water from causing the distillate concentration to be too low. A distillation time of 2-6 hours ensures the release of volatile components.

[0059] In the distillate, some of the volatile oils are suspended in the water as tiny droplets.

[0060] The technique of adding inorganic salts for salting out involves increasing the density of the aqueous phase, disrupting the binding state between water and oil droplets, and forcing the volatile oil droplets to aggregate and precipitate.

[0061] Extraction is performed using diethyl ether, which has extremely low polarity and a very low boiling point, to completely transfer the residual volatile oil from the aqueous phase. Anhydrous sodium sulfate, as a physical drying agent, absorbs any trace moisture entrained in the ether phase, ensuring the purity of the final volatile oil. The direct effect of this method is to obtain a high concentration of horseradish or mustard seed-specific odor substances, serving as the first olfactory signal to induce pests to feed.

[0062] The extraction of diamondback moth sex pheromones includes: collecting a large number of female diamondback moths through artificial rearing or field trapping.

[0063] The abdominal terminal tissue of female diamondback moths was collected by physical shearing. The collected abdominal terminal tissue was then immersed in hexane solvent and extracted at room temperature for 12-24 hours. After extraction, the tissue was physically filtered using filter paper or a microporous membrane to remove insect tissue residue. The filtrate was then purged under a nitrogen stream until the solvent was completely evaporated and the solution was concentrated to dryness, yielding the crude extract of diamondback moth sex pheromones.

[0064] The abdomen of the female diamondback moth is the organ for the secretion and physical storage of sex pheromones.

[0065] Sex pheromones are lipid-soluble compounds, and n-hexane is a commonly used nonpolar solvent that can effectively dissolve these lipid-soluble pheromones.

[0066] Soaking at room temperature for 12-24 hours ensures that the physical diffusion process of sex pheromones from biological tissues to the solvent phase reaches saturation.

[0067] In the solvent removal step, this scheme excludes conventional heating and vacuum evaporation methods, and instead limits the use of nitrogen gas purging and concentration. Diamondback moth sex pheromones are mostly unsaturated long-chain lipids, which are highly susceptible to oxidative breakage upon contact with oxygen in the air or under heating conditions.

[0068] Nitrogen is an inert gas with stable physical and chemical properties. Using a nitrogen flow to purge the gas can, on the one hand, carry away the n-hexane that has volatilized on the surface, thus accelerating the concentration process.

[0069] On the other hand, the nitrogen gas flow covering the liquid surface physically isolates it from oxygen in the air, effectively preventing the oxidative damage to the sex pheromone structure during the concentration process. This, in turn, preserves the chemical spatial configuration of the sex pheromone in its natural state, serving as a second, high-intensity olfactory signal to induce diamondback moth aggregation.

[0070] In this invention, the photosensitivity of the extract of *Bryum brevicornu* is enhanced under pH conditions of 8.5-10.0.

[0071] In a weakly acidic to neutral environment, the phenolic hydroxyl groups in the extract of *Brachys punctata* remain electrically neutral, the molecular structure is stable, and it is not sensitive to visible light.

[0072] When the composition is ingested by pests and enters the midgut, the strongly alkaline liquid in the midgut causes the hydrogen ions on the phenolic hydroxyl groups to detach, and the molecule is transformed into a negatively charged ionic form.

[0073] This structural change significantly enhances the molecule's efficiency in capturing photons of specific wavelengths. At this point, if the larva is irradiated with ultraviolet or blue light, the activated molecules absorb the light energy and transfer it to the surrounding dissolved oxygen. The oxygen is then activated into highly reactive singlet oxygen and hydroxyl radicals.

[0074] Reactive oxygen species then attack intestinal cell membranes, proteins, and chitin, causing cell rupture, protein degradation, and chitin breakage, thereby rapidly stopping pests from feeding and ultimately breaking them down into nutrients that can be absorbed by crops.

[0075] In this invention, the composition comprises, based on 1000 parts by weight:

[0076] Petroleum ether extract of *Bryum brevicornu*, 20-200 parts.

[0077] 10-100 parts of ethyl acetate extract of *Bryum brevicornu*

[0078] 5-50 parts of volatile oil extract from cruciferous plants.

[0079] 0.1-5 parts of crude extract of diamondback moth sex pheromone.

[0080] 10-100 parts of co-solvent, and the remainder water.

[0081] It should be noted that the petroleum ether phase extract is selected in quantities of 20-200 parts as the substrate for the subsequent photo-oxidation reaction. If the mass fraction is less than 20 parts, the total amount of substrate ingested by the pest in a single ingestion is insufficient to form a destructive oxidation reaction in the intestine; if the mass fraction is greater than 200 parts, the total amount of lipid-soluble substances is too large, exceeding the dispersion limit of the cosolvent, resulting in physical aggregation in water and uneven concentration of the pesticide solution.

[0082] The ethyl acetate phase extract, at a concentration of 0-100 parts, serves as a reaction rate regulator. This component primarily absorbs excess oxidative energy, preventing the insect's body from being excessively oxidized into volatile gases within a short period. Its dosage is adjusted according to the size of the target insect to ensure the final reaction product remains in a soluble fragment physical state.

[0083] The extracts consist of 5-50 parts of volatile oil from cruciferous plants and 0.1-5 parts of crude extract of diamondback moth sex pheromones.

[0084] The total amount of these two types of substances is controlled at a low level in order to utilize the physical diffusion properties of gaseous molecules. Low doses of volatile substances can create a physical concentration gradient covering several square meters in the air. If the amount used is too large, it will not only increase the manufacturing cost, but also cause high concentrations of odor molecules to keep the olfactory nerve receptors of pests in a continuous binding state, leading to olfactory fatigue and disorientation, making it impossible for them to accurately locate and feed on the composition.

[0085] In this invention, considering that the absorption efficiency of the extract of *Bryum brevicornu* in specific wavelengths of natural light is physically limited after activation in the intestines of pests, the composition also contains a natural photosensitizing synergist selected from crude chlorophyll extract, in an amount of 1-30 parts by weight.

[0086] The extraction of crude chlorophyll extract includes: taking fresh spinach, washing it, removing the coarse stems, pulverizing it with a tissue homogenizer, adding 2-5 times its volume of 95% ethanol, soaking and extracting at room temperature in the dark for 12-24 hours, filtering, and concentrating the filtrate under reduced pressure at 40-50℃ to one-fifth to one-tenth of its original volume to obtain crude chlorophyll extract. This extract is a dark green viscous liquid.

[0087] The technique of adding crude chlorophyll extract utilizes the high physical absorption rate of this substance across a wide range of visible light wavelengths.

[0088] In the composition, the crude chlorophyll extract acts as an energy-trapping antenna. After absorbing photon energy, it transfers the energy to the short-ribbed bud extract through physical collision and energy transfer pathways. The addition amount of 1-30 parts ensures that the physical distance between the crude chlorophyll extract molecules and the short-ribbed bud extract molecules in the dispersion system is short enough to facilitate energy transfer, thereby increasing the utilization rate of the composition to the ambient solar spectrum.

[0089] In this invention, the preparation of the composition includes: mixing the petroleum ether phase extract of *Bryum brevicornu*, the ethyl acetate phase extract, the volatile oil extract of cruciferous plants, the crude extract of diamondback moth sex pheromone, a solubilizer, a natural photosensitizing synergist, and water in a certain proportion, and stirring at 20-40°C for 10-30 minutes until uniformly dispersed.

[0090] The cosolvent is one or more of propylene glycol, glycerin, Tween 80, and Span 80, preferably a mixture of Tween 80 and Span 80 in equal proportions.

[0091] Add 10-100 parts of a co-solvent, selected from one or more of propylene glycol, glycerol, Tween 80, and Span 80, followed by the remaining water. Place the reactor containing the mixture under a stirrer, and at an ambient temperature of 20-40°C, set the stirring speed and continue stirring for 10-30 minutes until a physically uniform dispersion is formed.

[0092] It should be noted that the reason for adding a cosolvent is that there is a huge physical interfacial tension between petroleum ether phase, volatile oil and other fat-soluble substances and water, and the two will quickly separate into layers if mixed directly.

[0093] The combination of Tween 80 and Span 80 utilizes the amphiphilic nature of these surfactant molecules. Their lipophilic ends insert into the interior of the lipophilic droplets, while their hydrophilic ends extend into the aqueous phase, thereby forming a physical barrier film on the droplet surface. This barrier film reduces the tension at the oil-water interface.

[0094] It should be noted that the reason why the composition can achieve precise targeted destruction is that it utilizes the unique physiological parameters of the target pest as a special switch for the biochemical reaction.

[0095] In neutral or weakly acidic environments in nature, the polyphenols and anthraquinone macromolecules in the extract of *Bryum brevicornu* are in a closed and stable electrically neutral state, exhibiting reactive inertness. However, when this composition enters the bodies of lepidopteran larvae such as the diamondback moth during ingestion, it encounters their uniquely alkaline midgut environment.

[0096] Among them, the main active ingredients that exert photosensitizing and activating effects in the petroleum ether phase extract belong to anthraquinone compounds, including but not limited to: emodin, chrysophanol, emodin methyl ether, and polyphenolic compounds with ortho-phenolic hydroxyl structures, such as luteolin.

[0097] The above compounds exist in a weakly acidic to neutral environment in an electroneutrally neutral state with stable intramolecular hydrogen bonds, and the main UV-Vis absorption peak is located at 330-350 nm. When the pH is increased to 8.5-10.0, the phenolic hydroxyl groups on the anthraquinone and flavonoid molecules undergo deprotonation, the conjugated system expands, the absorption peak red-shifts to 370-390 nm, and the molar extinction coefficient increases, thereby obtaining photosensitizing activity.

[0098] Specifically, the extremely alkaline liquid forcibly strips hydrogen ions from the acidic groups on the surface of the extract molecules, triggering a deprotonation conformation. This structural change causes the electron cloud inside the molecule to delocalize and rearrange, significantly narrowing the energy level spacing, thus instantly transforming the originally light-insensitive molecule into a highly active photosensitive receptor.

[0099] After alkaline unlocking is completed, the insect's translucent body wall provides a physical channel for the intervention of special light. Specific wavelength photons that penetrate the insect's body wall directly irradiate the midgut and are captured in large quantities by these activated photoreceptors.

[0100] When a molecule absorbs light energy, its internal electrons are excited and jump to a high-energy state. Because the high-energy state is extremely unstable, the molecule will quickly transfer the excess energy or electrons directly to the oxygen molecules dissolved in the midgut fluid. This energy transfer disrupts the original stable state of the oxygen molecules, causing an instantaneous explosion inside the insect's gut and generating extremely high concentrations of singlet oxygen and reactive oxygen species such as hydroxyl radicals.

[0101] The explosive generation of reactive oxygen species is the direct cause of pests' absolute refusal to feed. These highly destructive free radicals wreak havoc in the gut, directly attacking the phospholipid bilayer of midgut epithelial cells and triggering a violent chain reaction of lipid peroxidation.

[0102] This not only leaves the intestinal cell membrane riddled with holes, completely losing its physical barrier function for digestion and absorption, but also causes the transmembrane potential to collapse instantaneously. The damage to the internal tissues of pests translates into extreme physiological stress and severe pain signals, directly impacting the pest's central nervous system.

[0103] Upon receiving a fatal crisis signal indicating intestinal collapse, the nervous system forcibly cuts off all feeding commands to the mouthpart muscles. Therefore, the moment pests suffer an internal oxidative attack, their chewing action is forced to completely and physically cease, exhibiting an irreversible and absolute refusal to eat, fundamentally ending further damage to crops.

[0104] During natural decomposition, insect biomass is often degraded by heterotrophic bacteria into ammonia gas that is volatilized and lost, or cross-linked with other soil minerals to form large molecular humic complexes that are difficult for plant roots to absorb directly.

[0105] Therefore, the embodiments of the present invention employ reactive oxygen species to induce pests to exhibit feeding refusal behavior and decompose the macromolecules of the pests to generate plant nutrients as a technical means.

[0106] The reason for using this reactive degradation technology is that the body surface of naturally dead insects is covered with a highly cross-linked chitinous exoskeleton, and the internal muscle tissue is composed of complex macromolecular proteins.

[0107] Macromolecular polymers in soil require enzymatic hydrolysis by exogenous saprophytic microorganisms for weeks to months to mineralize. During the microbial degradation process, ammonia volatilization and humic fixation are likely to occur, resulting in nutrient loss and biological fixation.

[0108] By instantly generating a high concentration of reactive oxygen species inside the midgut of pests, it directly attacks the phospholipid bilayer of midgut epithelial cells, triggering lipid peroxidation, damaging cell membrane structure and blocking nerve potential transmission, thus forcibly interrupting the pests' feeding actions.

[0109] At the same time, the extreme intracellular oxidative stress environment disrupts the metabolic homeostasis in insects, forcibly activating the insects' endogenous proteolytic enzymes and chitinases.

[0110] Reactive oxygen species, acting as oxidative destructive agents, work synergistically with endogenous enzymatic cleavage to physically cleave peptide and glycosidic bonds from the inside out, using the insect's own fat body, muscle protein, and chitinous exoskeleton as reaction substrates.

[0111] This technology solves the problems of long natural decay cycles of insect biomass and mismatch between nutrient release and crop nutrient requirements. It achieves the technical effect of simultaneously degrading the macromolecules of insect bodies into small, water-soluble free amino acids and chitosan oligosaccharide fragments as the pests die, so that the insect remains can be directly absorbed and utilized by the crop roots as fast-acting organic fertilizer.

[0112] The specific methods of applying the composition include:

[0113] During the growth period of cruciferous vegetables, including cabbage, Chinese cabbage, cauliflower, and rapeseed, when the population density of diamondback moth larvae in the field reaches the control threshold, usually 1-2 larvae per plant, pesticides are applied.

[0114] Dilute the above-prepared composition with water to a volume fraction of 0.1%-5%, that is, add 0.1-5L of the composition to every 100L of water and stir until homogeneous.

[0115] Using a conventional backpack sprayer or motorized sprayer, apply 30-50L of diluted solution per acre evenly to both sides of the vegetable leaves and the ground around the plants. Spraying should be done in the evening, 1-2 hours before sunset, or on a cloudy day to avoid premature decomposition of the solution on the leaves due to strong sunlight.

[0116] After spraying, the cruciferous plant volatile oil extract in the composition releases volatile substances such as allyl isothiocyanate. At the same time, the crude extract of diamondback moth sex pheromone attracts diamondback moth larvae from the surrounding area to gather in the sprayed area within 0.5-2 hours after spraying and they actively feed on the composition on the leaves.

[0117] When the larvae ingest the composition, the composition enters the midgut along with the food. The pH of the diamondback moth intestinal fluid is 8.5-10.0. In this strongly alkaline environment, the phenolic hydroxyl groups of the phenolic compounds in the extract of *Bryophytum brevicornu* undergo deprotonation, the molecular conjugated system expands, and its ultraviolet-visible absorption peak red-shifts from about 330 nm to about 380 nm.

[0118] At this point, with artificial lighting, the photosensitive component activated by the alkali absorbs light energy at a wavelength of 300-400nm, and the molecules enter a high-energy state. Subsequently, the obtained energy is directly transferred to the surrounding oxygen molecules, causing the oxygen molecules to transform into highly active singlet oxygen and hydroxyl radicals.

[0119] The generation of reactive oxygen species triggers the following chain reaction:

[0120] First, reactive oxygen species (ROS) attack the cell membranes of midgut epithelial cells, causing lipid peroxidation, disrupting membrane permeability and integrity, and leading to leakage of cell contents. Simultaneously, ROS inhibit the activity of superoxide dismutase, catalase, and peroxidase in the midgut, rendering the pest's own antioxidant defense system ineffective. The damage to midgut epithelial cells and oxidative stress from the mouthpart chemoreceptors cause larvae to exhibit strong anorexia 2-6 hours after light exposure, ceasing to feed on crop leaves.

[0121] Second, reactive oxygen species (ROS) continuously diffuse throughout the insect's body, attacking amino acid residues in protein molecules, leading to peptide bond breakage and side chain oxidation, thus decomposing proteins into free amino acids. Simultaneously, ROS act on the β-1,4 glycosidic bonds in chitin molecules, causing them to oxidize and break, degrading chitin into low-polymerization-degree chitosan oligosaccharides. This decomposition process occurs concurrently with larval death, typically completed within 6-24 hours after light exposure.

[0122] Insect carcasses containing high concentrations of free amino acids and chitosan oligosaccharides fall into the soil after death. The decomposition products do not require additional fermentation treatment and can be absorbed by the roots of cruciferous vegetables within 24-72 hours with the help of soil moisture and microorganisms.

[0123] Free amino acids, as readily available organic nitrogen sources, can directly participate in plant nitrogen metabolism; in addition to serving as a dual source of carbon and nitrogen nutrition, chitosan oligosaccharides can also be recognized by receptors on plant cell membranes, activating jasmonic acid and ethylene signaling pathways, inducing plants to produce defensive enzymes and phytoprotective agents, and enhancing crop resistance to subsequent diseases and pests.

[0124] Illumination is achieved using an array of ultraviolet LED lamps with a wavelength of 365±10nm and a light intensity of 5-8mW / cm². 2 Irradiate the area 1-2 hours after spraying for 10-20 minutes.

[0125] To verify the technical effect of the plant-derived biological control composition of the present invention, and to further explain the critical significance and synergistic mechanism of the component ratio ranges in the claims, the following experiment was designed for verification.

[0126] I. Experimental Sample Preparation and Group Design of Examples

[0127] The antifeeding activity of different concentrations of extracts of *Bryum brevicornu* on third-instar larvae of the diamondback moth was determined to identify the optimal concentration range.

[0128] II. Experimental Materials

[0129] The insect source used in the test was the third instar larvae of the diamondback moth, which were obtained through artificial rearing indoors. The rearing conditions were a temperature of 25±1℃, a relative humidity of 70%±5%, a photoperiod of L:D=16:8, and the host plant was cabbage.

[0130] Test plant: Cabbage leaves. Select plants that have grown for 30-40 days and have not been exposed to any pesticides, and collect the top 3-5 unfolded leaves.

[0131] Example 1: Based on 1000 parts by weight, take 20 parts of petroleum ether extract of *Bryum brevicornu*, 10 parts of ethyl acetate extract of *Bryum brevicornu*, 20 parts of volatile oil extract of cruciferous plants, 2 parts of crude extract of sex pheromones of *Plutella xylostella*, 40 parts of solubilizer, 20 parts of crude chlorophyll extract, and the remainder water.

[0132] The co-solvent was added to deionized water and stirred to dissolve. Then, the petroleum ether phase extract, ethyl acetate phase extract, volatile oil extract, crude extract of diamondback moth sex pheromone, and crude extract of chlorophyll were added sequentially. The mixture was stirred at 30°C for 15 minutes until uniformly dispersed to obtain the composition. The entire compounding process was carried out under light-protected conditions. After preparation, the mixture was transferred to a light-protected container and stored at 4-10°C under light protection. The composition was diluted with water to a volume fraction of 5%.

[0133] Use a 1.5 cm diameter punch to create leaf discs on cabbage leaves. 30 leaf discs are needed. Set up 3 replicates, using 10 third-instar larvae of the diamondback moth in each replicate. Total number of insects used = 7 groups × 3 replicates × 10 larvae = 210 larvae.

[0134] The diluted composition was sprayed onto the leaf discs for 30 seconds. One hour after spraying, a light intensity of 8 mW / cm² was applied at a wavelength of 365±10 nm. 2 Irradiate with ultraviolet light for 20 minutes.

[0135] Example 2: Similar to Example 1, except that 50 parts of the petroleum ether extract of *Bryum brevicornu* were used.

[0136] Example 3: It is largely the same as Example 1, except that 80 parts of the petroleum ether phase extract of *Bryum brevicornu* were used.

[0137] Example 4: Similar to Example 1, except that 110 parts of the petroleum ether extract of *Bryum brevicornu* were used.

[0138] Example 5: Similar to Example 1, except that 140 parts of the petroleum ether extract of *Bryum brevicornu* were used.

[0139] Example 6: Generally the same as Example 1, except that 170 parts of the petroleum ether phase extract of *Bryum brevicornu* were used.

[0140] Example 7: Generally the same as Example 1, except that 200 parts of the petroleum ether phase extract of *Bryum brevicornu* were used.

[0141] Detection method:

[0142] Midgut necrosis rate: Larvae were randomly collected 24 hours after drug administration, with 10 larvae per group. The midgut was dissected, and the percentage of necrotic area was calculated under a microscope.

[0143] Malondialdehyde content: determined by the thiobarbituric acid method, reflecting the degree of lipid peroxidation, unit nmol / mg protein.

[0144] Superoxide dismutase inhibition rate: The WST-1 method was used to determine the percentage of SOD activity inhibition in the treatment group relative to the control group.

[0145] Calculation of food refusal rate:

[0146] A control group was set up, and the leaf discs were collected in the same manner as in Example 1. Thirty third-instar larvae of diamondback moth were used for three replicates, but the composition was not sprayed.

[0147] Refusal to eat rate = (Food consumption area of ​​control group - Food consumption area of ​​treatment group) / Food consumption area of ​​control group × 100%.

[0148] Performance tests were performed on Examples 1-7, and the obtained data are compiled into Table 1, as follows: Figure 1 As shown.

[0149] Table 1:

[0150] Midgut tissue necrosis rate (%) Malondialdehyde content (nmol / mg protein) Superoxide dismutase inhibition rate (%) 24-hour food refusal rate (%) Example 1 0.85±0.12 3.42±0.21 18.5±3.2 20±3 Example 2 1.62±0.15 5.68±0.32 35.2±4.1 50±6 Example 3 2.48±0.18 8.95±0.45 58.7±5.3 70±7 Example 4 3.56±0.12 12.28±0.52 86.4±4.8 85±9 Example 5 3.12±0.14 11.15±0.48 78.3±5.1 80±8 Example 6 2.65±0.16 9.86±0.41 65.2±4.5 70±7 Example 7 2.08±0.13 7.24±0.35 48.6±3.9 60±6

[0151] Comparative examples 1-7 show that as the concentration of the petroleum ether extract of *Phyllostachys brevis* gradually increases, the various properties improve. This is mainly because the petroleum ether extract of *Phyllostachys brevis* is the core substrate material for the photooxidative degradation reaction. As its concentration increases, the total amount of photosensitive precursor substances ingested by the diamondback moth into the digestive tract increases significantly.

[0152] In the highly alkaline midgut environment unique to the diamondback moth, more precursor molecules undergo deprotonation and conformational changes. Upon excitation by light, these molecules can instantly generate extremely high concentrations of reactive oxygen species (ROS). These high concentrations of ROS launch a strong lipid peroxidation attack on the midgut cell membranes of the pest, completely overwhelming the pest's antioxidant defense system and causing irreversible midgut tissue necrosis. This generates intense physiological pain signals, forcibly interrupting the pest's feeding behavior, causing various indicators of food rejection and damage to reach their peak in Example 4.

[0153] However, after Example 4, as the petroleum ether phase extract of *Bryum brevicornu* continued to increase, the performance decreased. This was mainly because the petroleum ether phase extract is a highly lipophilic nonpolar substance. When its addition amount was too large, the total amount of the huge lipophilic material exceeded the physical dispersion and emulsification limit of the fixed cosolvent.

[0154] Excessive nonpolar oil phase cannot be completely encapsulated by surfactants, resulting in physical aggregation and droplet fusion within the system. This leads to a significant decrease in the effective specific surface area of ​​the dispersion and uneven distribution of pesticide concentration. This deterioration in the physiorheological state hinders the uniform contact and receptor binding of the active ingredient within the insect's gut, reduces the physical mass transfer efficiency during photoexcitation, and consequently decreases the effective reaction scale capable of generating reactive oxygen species, thus diminishing the macroscopic control performance.

[0155] Example 8: Similar to Example 4, except that 20 parts of the ethyl acetate phase extract of *Bryophytum brevicornu* were used.

[0156] Example 9: Similar to Example 4, except that 40 parts of the ethyl acetate phase extract of *Bryophytum brevicornu* were used.

[0157] Example 10: Similar to Example 4, except that 60 parts of the ethyl acetate phase extract of *Bryophytum brevicornu* were used.

[0158] Example 11: Similar to Example 4, except that 80 parts of the ethyl acetate phase extract of *Bryophytum brevicornu* were used.

[0159] Example 12: Similar to Example 4, except that 100 parts of the ethyl acetate phase extract of *Bryophytum brevicornu* were used.

[0160] The data obtained from Examples 8-12 are integrated as shown in Table 2, and as follows: Figure 2 As shown.

[0161] Table 2:

[0162] Midgut tissue necrosis rate (%) Malondialdehyde content (nmol / mg protein) Superoxide dismutase inhibition rate (%) 24-hour food refusal rate (%) Example 8 3.86±0.11 12.88±0.12 85.4±4.2 86±5 Example 9 3.98±0.16 13.81±0.11 86.1±2.7 87±2 Example 10 4.26±0.11 15.23±0.21 88.6±3.1 91±2 Example 11 3.96±0.18 14.28±0.52 87.4±1.2 88±3 Example 12 3.52±0.13 12.07±0.24 85.3±2.7 87±1

[0163] Comparative examples 8-12 show that as the ethyl acetate phase extract of *Bryum brevicornu* is gradually increased, various properties improve. This is mainly because the ethyl acetate phase extract of *Bryum brevicornu* is rich in moderately polar polyphenols and flavonoids. These substances can act as electron donors and reaction intermediate carriers in the photodynamic destruction reaction, producing a significant synergistic physical effect with the petroleum ether phase extract. Appropriate addition expands the overall absorption spectrum of the composition to environmental photon energy, prolongs the physical survival time of excited-state molecules, thereby further increasing the total amount of instantaneous reactive oxygen species in the midgut of the pest, intensifying the lipid peroxidation chain reaction of intestinal cell membranes, resulting in a significant increase in malondialdehyde content, leading to tissue necrosis and the peak of the antifeeding effect in Example 10.

[0164] However, after Example 10, as the ethyl acetate extract of *Bryum brevicornu* continued to increase, the performance decreased, mainly because the ethyl acetate extract also acts as a reaction energy buffer in the system. When its addition ratio is too high, the excess polyphenols exhibit strong free radical scavenging properties, excessively absorbing and quenching reactive oxygen free radicals generated in the system through sacrificial oxidation of their own structure. This overload of physical buffering effect leads to the self-cancellation of internal destructive energy, prematurely blocking the continuous physical cutting and destruction pathway of the pest's midgut tissue, ultimately resulting in a comprehensive decline in macroscopic properties such as destruction rate, enzyme inhibition rate, and feeding refusal rate.

[0165] Comparative Example 1: It is largely the same as Example 10, except that it is not subjected to light treatment, but is covered with a light-blocking net to keep it in darkness for 24 hours.

[0166] Comparative Example 2: largely the same as Example 10, except that the cruciferous plant volatile oil extract and the diamondback moth sex pheromone crude extract were removed.

[0167] Comparative Example 3: Largely the same as Example 10, except that the crude chlorophyll extract was removed.

[0168] Comparative Example 4: A chemical pesticide comparison was made using 2.5% cyhalothrin emulsifiable concentrate diluted 2000 times.

[0169] Detection method:

[0170] Protein decomposition rate of insect bodies: The total protein content of dead insect bodies was determined by BCA method and compared with the protein content of the blank control group to calculate the decomposition rate.

[0171] Increase in available nitrogen in soil: The dead insect bodies were buried in a pot containing 100g of soil. After 7 days, the alkaline available nitrogen content was measured and the background value of the soil without buried insect bodies was subtracted.

[0172] The data obtained from Comparative Examples 1-4 are integrated as shown in Table 3.

[0173] Table 3:

[0174] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Midgut tissue necrosis rate (%) 0.85±0.10 2.48±0.18 3.56±0.15 5.62±0.35 Malondialdehyde content (nmol / mg protein) 2.65±0.18 8.56±0.35 12.28±0.45 18.52±0.65 Superoxide dismutase inhibition rate (%) 18.5±2.5 58.7±4.0 86.4±4.0 92.5±3.5 24-hour food refusal rate (%) 22±3 65±5 85±5 95±3 Protein breakdown rate (%) 8.5±1.2 38.5±3.0 72.5±3.8 12.5±1.5 Increase in available nitrogen in soil (mg / kg) 5.2±0.8 22.5±2.0 38.5±3.0 6.5±0.9

[0175] As can be seen from the data in Comparative Example 1, when a shading net is used to maintain darkness, all destructive indicators drop drastically. This is mainly because the core killing mechanism of this composition relies on the physical input of external photon energy. In a dark environment lacking light, even if the pests have ingested a large amount of the pesticide and completed initial activation in their alkaline intestines, the activated material cannot capture energy and transfer it to oxygen due to the lack of external light, and the in-situ oxidation and destruction reaction cannot be initiated at all.

[0176] The data from Comparative Example 2 show that removing cruciferous volatile oils and sex pheromones significantly reduced the control effect. This is mainly because the physical induction and olfactory deception of specific odor molecules were lost, and the composition revealed the inherent physical odor of the plant extracts. Pests instinctively developed a taste rejection, degenerating from active gorging to passive, minimal contact. The total amount of effective material swallowed into the digestive tract was drastically reduced, far from reaching the physical scale needed to cause large-scale tissue damage in the intestines, resulting in a significant reduction in both the final lethality and degradation output.

[0177] The data from Comparative Example 3 show that, although the chlorophyll crude extract still exhibits good insecticidal effects after removal, the upper limit of oxidative damage and the protein decomposition rate both decline to some extent compared to the optimal Example 8. This is mainly because the pure *Brucea brevis* extract has a relatively narrow physical absorption band for natural visible light. The absence of the chlorophyll crude extract reduces the composition's efficiency in intercepting and absorbing overall transmitted photons from the environment. The reduced total energy delivered to the pest's body slows down the intensity of physical cutting of the pest's macromolecular tissues, preventing the fertilizer conversion rate from reaching its peak.

[0178] The data from Comparative Example 4 shows that while conventional chemical pesticides cause extremely high rates of midgut necrosis and feeding refusal due to their direct neurotoxicity, their protein decomposition rate is only 12.5%, and their increase in available nitrogen in the soil is the lowest. This is mainly because chemical poisons only physiologically kill insects. After being poisoned, the insects remain in a solid, limp state with their bodies intact, unable to release internal nutrients. This objectively and strongly demonstrates that the unique photo-induced in vivo destruction reaction of the composition of this invention, while achieving equivalent or even better control effects, breaks down the insect body into liquid, fast-acting fertilizer in situ, solving the inherent defect of traditional chemical pesticides that can only kill insects but cannot be converted into fertilizer.

[0179] Application of a plant-derived biocontrol composition as an insecticide alternative in biocontrol agents.

[0180] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A plant-derived biocontrol composition as an insecticide substitute, characterized in that, The composition comprises, based on 1000 parts by weight: Petroleum ether extract of *Bryum brevicornu*, 20-200 parts. 10-100 parts of ethyl acetate extract of *Bryum brevicornu* 5-50 parts of volatile oil extract from cruciferous plants. 0.1-5 parts of crude extract of diamondback moth sex pheromone. 10-100 parts of co-solvent, and the remainder water.

2. The plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The preparation of the petroleum ether phase extract of the short-ribbed feather moss includes: The dried whole herb of *Bryum shortribum* was pulverized to 20-80 mesh, and 95% ethanol at a mass-to-volume ratio of 1:5-15 was added. The mixture was refluxed at 60-80℃ for 2-4 times, each time for 1-3 hours. The extracts were combined and concentrated under reduced pressure at 40-50℃ until no alcohol odor was detected, thus obtaining the extract. Dissolve the extract in 10-50 times its weight of water, extract with an equal volume of petroleum ether 2-4 times, combine the petroleum ether phases, and evaporate to dryness under reduced pressure at 40-50℃ to obtain the final product.

3. The plant-derived biocontrol composition as an insecticide substitute according to claim 2, characterized in that: The preparation of the ethyl acetate phase extract of the short-ribbed feather moss includes: The aqueous phase after petroleum ether extraction is extracted 2-4 times with an equal volume of ethyl acetate. The ethyl acetate phases are combined and evaporated to dryness under reduced pressure at 40-50℃ to obtain the final product.

4. The plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The photosensitivity of the extract of *Bryum brevicornu* is enhanced under pH conditions of 8.5-10.

0.

5. The plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The cruciferous plant volatile oil extract includes: volatile substances from cruciferous plants; The volatile oil extract from the cruciferous plants is horseradish volatile oil extract or mustard seed volatile oil extract, which is extracted by steam distillation: the plant tissue is crushed, 2-5 times the mass of water is added, and steam distillation is carried out for 2-6 hours. The distillate is collected, and after salting out, ether extraction, drying with anhydrous sodium sulfate, the ether is evaporated to obtain the extract.

6. The plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The crude extract of diamondback moth sex pheromone includes: diamondback moth sex pheromone; The extraction of sex pheromones from the diamondback moth includes: collecting the abdominal end of female diamondback moths, soaking them in hexane for 12-24 hours, filtering, and concentrating the filtrate to dryness under a nitrogen stream to obtain a crude extract of sex pheromones.

7. A plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The composition further comprises a natural photosensitizing synergist selected from crude chlorophyll extract, used in an amount of 1-30 parts by weight.

8. The plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The composition preparation includes: mixing the petroleum ether phase extract, ethyl acetate phase extract, cruciferous plant volatile oil extract, diamondback moth sex pheromone crude extract, solubilizer, natural photosensitizing synergist, and water in a certain proportion, and stirring at 20-40℃ for 10-30 min until uniformly dispersed.

9. A plant-derived biocontrol composition as an insecticide substitute according to claim 1, characterized in that: The cosolvent is one or more of propylene glycol, glycerin, Tween 80, and Span 80.

10. The use of a plant-derived biocontrol composition as an insecticide substitute according to any one of claims 1-9 in a biocontrol agent.

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