A method for controlling the population of *Papaver rhoeas* by using interspecific competition among *Papaver somnifera* mealybugs.

Abstract

The present invention belongs to the technical field of interspecific competition and exclusion of agricultural pests, and discloses a method for controlling the population of Psoralea chinensis using interspecific competition of Psoralea rosae, aiming to solve the problems of drug resistance, pesticide residues, ecological damage, and poor timeliness and stability of biological control in existing prevention and control methods. The method for controlling the population of Psoralea chinensis using interspecific competition includes: screening, breeding, and restarting the physiological functions of Psoralea rosae that have no host adaptability to papaya, and accurately calculating the inoculation dose based on the density of Psoralea chinensis, and accurately inoculating through an electrostatic adsorption synergistic carrier. The method utilizes the interspecific competition between Psoralea rosae and Psoralea chinensis to efficiently and quickly exclude and inhibit Psoralea chinensis, and the Psoralea rosae naturally dies out due to its non-host adaptability, thereby achieving green and risk-limiting pest control.

Description

Technical Field

[0001] This invention belongs to the field of interspecific competitive exclusion technology of agricultural pests, and specifically relates to a method for controlling the population of papaya mealybug by using interspecific competitive exclusion of papaya mealybug by the hibiscus mealybug. Background Technology

[0002] pawpaw( Papaya Carica As a landmark tropical and subtropical economic crop in southern my country, the scale and economic value of the papaya industry are increasingly prominent. However, the stable and sustainable development of this industry is facing challenges due to the invasive pest, the papaya mealybug (L.). Paracoccus marginatus This pest poses a severe challenge. Due to its strong environmental adaptability and reproductive capacity, it has rapidly established itself and spread explosively in major producing areas. Its nymphs and adults gather on the tender tissues of papaya plants, such as young leaves, stems, and fruit surfaces, using their piercing-sucking mouthparts to continuously suck plant sap, directly depriving the plant of nutrients and hindering its growth and development. Even more seriously, the large amounts of honeydew secreted during feeding provide an ideal culture medium for the pathogens of sooty mold, inducing large-scale outbreaks of sooty mold, severely affecting leaf photosynthesis, and causing the fruit surface to be covered with a black mold layer, rendering it unmarketable and causing significant economic losses to the papaya industry.

[0003] To combat the damage caused by the papaya mealybug, current agricultural practices primarily rely on chemical control methods, namely the application of systemic or contact insecticides such as thiamethoxam and spirotetramat. In the early stages of an outbreak, this method, with its rapid action and high killing efficiency, can quickly suppress the pest population in the field, providing a direct and effective solution for controlling the spread of the infestation. Correspondingly, the combination or rotation of chemical agents with different mechanisms of action constituted standard operating procedures for dealing with such sudden outbreaks of pests during specific historical periods. Building upon this foundation, with the deepening of green agriculture and ecological sustainable development concepts, biological control technologies centered on the introduction of natural enemies have also been partially applied, such as the large-scale release of parasitic wasps or predatory natural enemies like the ladybug. This technical approach aims to establish a "predator-prey" relationship, creating a sustained suppressive force against target pest populations within the farmland ecosystem. Its initial goal is to reduce dependence on chemical pesticides and protect farmland biodiversity.

[0004] However, with the increasing intensification of the papaya industry and the more stringent requirements for agricultural product quality and safety as well as the impact on the ecological environment, some inherent characteristics of the two mainstream control technologies mentioned above have gradually revealed deep-seated contradictions and limitations in addressing new challenges. For chemical control, its non-selective and coercive intervention mechanisms have led to a series of chain reactions and negative effects. Long-term, high-frequency application of a single type of pesticide inevitably exerts strong directional selection pressure on the papaya mealybug population, resulting in a significant increase in the frequency of resistance alleles and a gradual decrease in control effectiveness. Farmers are forced to increase dosage or frequency to maintain efficacy, creating a vicious cycle. Simultaneously, as a crop that flowers continuously and is harvested in batches, papaya's short fruit harvesting interval naturally contradicts the necessary safety interval for chemical pesticides, easily leading to food safety risks such as excessive pesticide residues. A deeper problem is that while broad-spectrum insecticides kill mealybugs, they also indiscriminately kill pollinating insects and endogenous natural enemies such as ladybugs and lacewings, disrupting the original self-regulating capacity of the farmland ecosystem and making it easier for pest populations to rampage again after the pesticide's effects wear off.

[0005] On the other hand, while biological control technology is more eco-friendly in concept, its operational logic is fundamentally mismatched with the explosive population dynamics of the papaya mealybug. Biological control relies on the successful establishment and propagation of natural enemy populations and the formation of stable interactions with the pest population—a relatively slow ecological process highly influenced by environmental factors. The reproductive rate, environmental adaptability, and search efficiency of natural enemies in vast fields often lag far behind the exponential growth rate of R-strategy pests like the papaya mealybug. Therefore, in emergency situations where pest population density has reached the damage threshold, releasing natural enemies often fails to achieve immediate suppression effects, exhibiting a significant time lag. Furthermore, the large-scale breeding of natural enemies is costly, and their survival rate after release in the field is easily affected by various uncontrollable factors such as climate and farming practices, resulting in unstable application effects and insufficient coverage in large-scale commercial cultivation. In recent years, the "using insects to control insects" approach, which utilizes interspecific competition between non-target pests and target pests, has opened up new avenues for pest control. However, current practices often remain at the macro-level of concepts, lacking precise assessment and screening of the ecological niche overlap, competitive exclusion efficiency, and host plant adaptability between competing species and target pests. Blindly introducing an external species, if it also possesses strong host adaptability and reproductive potential, could very likely transform from a regulatory factor into a new secondary pest, triggering more complex ecological problems.

[0006] Therefore, how to transcend the strong interference mode of traditional chemical control and the time-limited bottleneck of biological control, and find a new regulatory mechanism that can quickly respond to the explosive growth of papaya mealybugs, while having a clear action path, controllable risks, and high compatibility with farmland ecosystems, namely, developing a new "pest-pest" ecological regulation system based on precise matching of species competition relationships, achieving short paths, quick results, and environmental friendliness, has become a key technical problem that urgently needs to be solved in the field of green control of papaya pests. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of pesticide resistance, pesticide residues, and ecological damage caused by existing chemical control methods, as well as the limitations of biological control technologies in dealing with the explosive population growth of papaya mealybugs, such as delayed effectiveness, high cost, and unstable results. To achieve this objective, this invention provides a method for controlling papaya mealybug populations by utilizing interspecific competition from hibiscus mealybugs. This method, based on in-depth analysis and engineering application of specific interspecific competition mechanisms, establishes a biological regulation technology system that is rapid-response, precise in action, self-limiting in risk, and highly compatible with farmland ecosystems. This system introduces a competitive organism that has undergone special physiological function reactivation treatment and lacks host adaptability to papaya, instantly establishing an overwhelming resource dominance within the local ecological niche of the papaya plant. This rapidly displaces and suppresses the target pest, papaya mealybug, ultimately achieving the goal of efficiently and greenly controlling pest damage without introducing new ecological risks.

[0008] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for controlling the population of *Papaver rhoeas* by using interspecific competition among *Papaver somnifera* mealybugs includes the following steps:

[0010] S1. Preparation of a targeted competitive biocontrol agent: The hibiscus mealybug, which lacks host adaptability to the papaya plant, is selected, and its physiological functions are restarted through a two-stage treatment including starvation stress and refeeding vitality response. The mechanism for selecting this specific species is that it highly overlaps with the target pest, the papaya mealybug, in terms of ecological niche requirements, including feeding preferences for phloem sap of the host plant, aggregation behavior patterns on the plant surface, and similar temperature and humidity adaptation ranges, thus forming the biological basis for intense interspecific competition. At the same time, the hibiscus mealybug lacks host adaptability to the papaya plant (Carica papaya L.) and cannot complete its full life cycle on the papaya plant. This characteristic constitutes the core of the self-limiting risk of the technical solution of this invention.

[0011] S2. Quantitative assessment of the population density of the target pest: In the target field, a systematic sampling survey and quantitative assessment of the population density of the papaya mealybug parasitizing the papaya plants was conducted to determine whether the threshold for initiating intervention was reached.

[0012] S3. Determination and Implementation of Inoculation Program: Based on the population density of *Papaya mealybug* assessed in S2, the inoculation dose of *Papaya mealybug* is accurately calculated using a preset competitive pressure index model. The *Papaya mealybug* is mixed with a micro-powdered synergistic carrier and then positively charged using an electrostatic spraying device. Electrostatic attraction is used to inoculate the carrier onto the papaya plants, thereby establishing a resource dominance against *Papaya mealybug* in the local ecological niche of the papaya plants, achieving rapid competitive exclusion and suppression of the *Papaya mealybug* population.

[0013] Furthermore, the preparation of the targeted competitive biocontrol agent further includes, prior to the physiological function restart treatment, standardized breeding of the hibiscus mealybug, wherein the standardized breeding includes:

[0014] (1) In an insect rearing cage with controlled environmental parameters, potted hibiscus was used as the host plant, and the ancestral population of hibiscus mealybug was inoculated and allowed to reproduce and expand naturally.

[0015] (2) When the population density of the hibiscus mealybug reaches the preset collection threshold of more than 50 individuals per square centimeter of leaf area, collection shall be carried out;

[0016] (3) The collection operation is specifically limited to collecting female adult insects that are pregnant with eggs. The morphological characteristics of the female adult insects are that their bodies are covered with white wax powder, their body length reaches 2.5 mm to 3.5 mm, and their abdomen is obviously bulging. The collection process is carried out by gently sweeping off the eggs with a soft brush or collecting them with a negative pressure insect aspirator to avoid physical damage to the insects.

[0017] Furthermore, the environmental parameters maintained within the insect rearing cage are as follows:

[0018] (1) The temperature is controlled at 27 degrees Celsius by a two-way temperature control system, with a fluctuation range not exceeding ±1 degree Celsius;

[0019] (2) The relative humidity is maintained at 70% by an ultrasonic atomization humidification system, with fluctuations controlled within ±5%.

[0020] (3) The photoperiod is set to a 14-hour light cycle and a 10-hour dark cycle using full-spectrum LED plant growth lights.

[0021] Furthermore, the physiological function restart treatment of the hibiscus mealybug is to ensure that the introduced hibiscus mealybug can instantly exhibit the strongest colonization and feeding competitiveness after being released into the papaya plant, thereby gaining an absolute advantage in the initial competition with the papaya mealybug. This specifically includes two stages executed sequentially:

[0022] (1) The first stage is the starvation stress stage: The collected female adult hibiscus mealybugs were placed in a sealed container without host plants and lined with dry filter paper. Under the environmental conditions of 25 degrees Celsius and 60% relative humidity, they were subjected to continuous starvation treatment for 12 hours to interrupt the nutrient supply and activate their later feeding behavior.

[0023] (2) The second stage is the refeeding vitality response stage: the female adult insects that have been subjected to hunger stress are transferred to a new container with a bottom of absorbent cotton soaked in a specific refeeding vitality response solution. The female adult insects are placed in this environment for 2 hours so that they can eat a small amount to restore their strength and further activate their feeding behavior.

[0024] After undergoing this physiological function restart treatment, the frequency of probing behavior of the hibiscus mealybug when it comes into contact with the surface of a new host plant increases by 30% to 50% compared to untreated individuals, and the time to first successful feeding is shortened by 40% to 60%.

[0025] Furthermore, the refeeding vitality response solution in the refeeding vitality response phase comprises, by weight percentage: 10% sucrose as a high-energy carbon source; 1% yeast extract powder to provide B vitamins, amino acids, and trace elements; and 89% deionized water. After completing the refeeding vitality response phase, the female adults undergo a secondary screening process, with weak or dead individuals removed by physical contact to ensure that the targeted competitive biocontrol agent used for field release possesses high physiological activity and behavioral consistency.

[0026] Furthermore, the quantitative assessment of the population density of the hibiscus mealybug, in order to determine the threshold for initiating intervention and to provide a data basis for subsequently calculating the precise inoculation amount of the hibiscus mealybug, specifically employs a random sampling method, which includes:

[0027] (1) Randomly select 10 papaya leaves in the target field using the diagonal method, prioritizing mature leaves that are fully expanded in the upper part of the canopy, with the back side as the main inspection area;

[0028] (2) For each sample plant, select the third fully unfolded leaf from the top of the canopy downwards;

[0029] (3) Use a 1 cm² grid transparent calibration sheet to cover the pest gathering area on the back of the leaf, count the total number of nymphs and adults of Papaya mealybug in the grid, check 3 random 1 cm² areas on each leaf, take the average value as the pest density (heads / cm²) of the leaf, summarize the density data of 10 leaves, calculate the average number of insects per leaf, and then convert it into the total number of insects per 10 leaves, which is the average population density in the field.

[0030] (4) The action threshold for initiating intervention determined by this method is: when the average population density in the field exceeds 100 heads / 10 leaves, the subsequent inoculation steps are initiated.

[0031] Furthermore, the step of accurately calculating the inoculation dose of the hibiscus mealybug using a preset competitive pressure index model is key to achieving a rapid and efficient competitive exclusion effect in this invention. Its core basis is a "competitive pressure index model" based on interspecific competition dynamics. The goal of this model is to ensure that the comprehensive competitive pressure generated by the introduced hibiscus mealybug population can significantly exceed the defensive capacity of the field papaya mealybug population. The competitive pressure index (CPI) is calculated as follows: CPI = (N_c × V_c × I_f) / (N_t × V_t).

[0032] Where N_c is the number of hibiscus mealybugs planned to be inoculated on every 10 leaves;

[0033] N_t represents the actual number of papaya mealybugs per unit area measured in S2;

[0034] V_c is the colonization vitality coefficient of the hibiscus mealybug after physiological function restart treatment. This coefficient characterizes its ability to seize space and feeding sites. The experimental method for determining the colonization vitality coefficient (V_c) is as follows: In a standardized indoor environment, hibiscus mealybugs that have undergone physiological function restart treatment and untreated individuals are simultaneously inoculated onto papaya seedlings at a ratio of 1:1. After 24 hours, the proportion of individuals that have successfully colonized (established feeding sites) in the two treatments is counted and calculated. This proportion is V_c. According to the experimental results, its value is set to 1.4.

[0035] V_t is the conservation viability coefficient of Papaver rhoeas under natural field conditions, with a baseline value set at 1.0;

[0036] I_f is the interspecific interference coefficient, which characterizes the physical interference effect of the presence of *Hibiscus mealybug* on the reproductive behavior (such as mating and oviposition) of *Papaya mealybug*. The experimental method for determining the interspecific interference coefficient (I_f) is as follows: In a controlled environment of 25±1℃ and 70±5% humidity, equal amounts of *Hibiscus mealybug* and *Papaya mealybug* (10 individuals / plant) were inoculated into papaya seedlings, and the inoculation was repeated 10 times. The interaction between the two mealybug species was continuously recorded for 24 hours using a high-definition camera system. The focus was on observing the frequency and duration of the direct driving behavior of *Hibiscus mealybug* on *Papaya mealybug*, the competition for feeding sites, and the mating interference behavior. After the experiment, video analysis software was used to quantify the degree of decline in feeding efficiency and the reduction in activity range of the papaya mealybug. Combined with the intensity of the interference behavior, the formula I_f = (feeding efficiency of control group - feeding efficiency of treatment group) / feeding efficiency of control group × behavior frequency correction coefficient was used for calculation. After three independent repeated experiments, the final value of I_f was determined to be 1.2.

[0037] Furthermore, to achieve rapid suppression of the papaya mealybug population, the CPI value calculated according to the formula is set to be greater than 1.5. Based on this, the ratio of the inoculation quantity N_c of the hibiscus mealybug to the field-measured quantity N_t of the papaya mealybug needs to be greater than 0.89. To meet this condition and considering the redundancy and operational errors in field application, this invention determines that the preferred ratio of the inoculation quantity N_c of the hibiscus mealybug to the field-measured quantity N_t of the papaya mealybug is 1:1. That is, if the average density of the papaya mealybug is measured to be 10 individuals / 10 leaves, then the inoculation density of the hibiscus mealybug should also be 10 individuals / 10 leaves. The inoculation time is selected within 72 hours after the population density of the papaya mealybug reaches or just exceeds the action threshold to ensure that intervention is applied before the target pest population enters the exponential growth outbreak period.

[0038] Furthermore, the precise inoculation using an enhanced carrier delivery system based on electrostatic adsorption is to solve the technical challenge of uniformly and efficiently placing tiny mealybug individuals onto specific parts of the papaya plant, specifically including:

[0039] (1) The female adult mealybugs of the hibiscus that have undergone physiological function restart treatment are gently mixed with a micro-powdered synergistic carrier at a weight ratio of 1:30 to form a carrier-mealybug complex. The mixing process is carried out in a rolling mixer with a rotation speed of 10 revolutions per minute to ensure that the mealybugs are uniformly attached to the carrier particles while avoiding physical damage. The synergistic carrier is a micro-powder composed of biocompatible materials. Its components, on a dry weight basis, include: 90% potato starch as the main skeleton; 8% sodium alginate as a moisturizing and adhesive agent; and 2% L-serine as a short-term nutritional supplement and feeding attractant. After these components are fully mixed, they are processed by an air jet mill to produce a homogeneous powder with an average particle size of 50 to 100 micrometers.

[0040] (2) A portable electrostatic powder spraying device is used for inoculation. The device is equipped with a high-voltage corona discharge needle at the powder outlet so that the carrier-mealyptus complex is charged with a positive charge when it is sprayed out.

[0041] (3) Taking advantage of the fact that the surface of plant leaves and stems usually carries a negative charge, the positively charged composite is preferentially and firmly adsorbed onto the surface of the papaya plant through electrostatic attraction, especially the back of the leaves, leaf axils and stem crevices, which are places where papaya mealybugs can easily hide.

[0042] This inoculation method not only significantly improves the uniformity and targeting of inoculation, but also greatly increases the initial adhesion rate of mealybugs on the plant surface, reducing losses caused by wind or mechanical vibration. The operator holds an electrostatic powder spraying device about 50 cm away from the papaya plant canopy and sprays evenly from top to bottom until the leaves and stems are covered with a thin layer of carrier powder.

[0043] After inoculation, the field ecosystem enters a phase of intense interspecific competition dominated by this invention, the mechanism of which includes two levels:

[0044] (1) At the level of resource exploitation competition, the hibiscus mealybug, after undergoing physiological function restart treatment, will quickly seize the best feeding sites on the papaya plant, namely the tender tissues with dense distribution of phloem sieve tubes, due to its extremely high colonization vitality. Since these sites are limited, the hibiscus mealybug's priority occupation directly deprives the papaya mealybug of its food source, leading to malnutrition, hindered growth and development, and a significant decrease in reproductive capacity.

[0045] (2) At the level of physical interference competition, the high-density population of hibiscus mealybug forms a biological barrier in space. This physical crowding seriously interferes with the normal behavior of hibiscus mealybug. For example, it hinders male adults from finding and mating with female adults, interferes with female adults from finding suitable oviposition sites, and even the honeydew and wax powder secreted by them cover the egg sacs of hibiscus mealybug, reducing the hatching rate of the eggs.

[0046] On days 7, 14, 21, and 28 post-inoculation, the population densities of *Papaver rhoeas* and *Hibiscus mealybug* in the field were simultaneously monitored again using the same method described in S2. The control effect was judged by a population density reduction rate of over 85% for *Papaver rhoeas* within 21 days post-inoculation. Simultaneously, monitoring data showed that the population of *Hibiscus mealybug* began to decline sharply after day 21 and was essentially undetectable in the field by day 35.

[0047] Furthermore, the method further includes a preferred synergistic step:

[0048] (1) After suppressing the population density of the papaya mealybug to a preset low level of less than 2 heads / 10 leaves by the method described above, a clean environment without chemical pesticide residues is formed in the field. At this time, a small number of obligate parasitic wasps of the papaya mealybug, such as the aphid wasp, or predatory natural enemies, such as the ladybug, are selectively released into the field.

[0049] (2) By utilizing the high clearance efficiency of the natural enemy insects in a low pest population environment, the remaining papaya mealybugs are cleared and a self-sustaining, long-term stable low-density regulated ecological balance is established, thereby achieving an organic combination of short-term rapid suppression and long-term stable control.

[0050] The beneficial effects of this invention are:

[0051] This invention discloses a method for controlling the population of *Hibiscus mealybug* by excluding *Papaya mealybug* through interspecific competition. This method constructs a complete and engineerable technical process through precise screening of competing biological species, physiological function reactivation treatment, model-based quantitative inoculation, and precise delivery using electrostatically enhanced carriers. The method leverages the high degree of niche overlap between *Hibiscus mealybug* and *Papaya mealybug* to trigger intense interspecific competition, while utilizing the non-host adaptability of *Hibiscus mealybug* to papaya to ensure its own risk self-limitation. This invention fundamentally solves the environmental and safety problems caused by chemical control and the problem of poor timeliness in biological control, providing a novel, highly original, and practical technical solution for the green and efficient control of explosive pests in intensive agricultural production. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions of this invention, the present application will be further described in detail below with reference to embodiments. Example 1

[0053] On June 5, 2024, a comprehensive pest survey was conducted in a 2-hectare commercial papaya plantation located in Jiangnan Town, Nanning City, Guangxi Province, using the random sampling method described in this invention. The survey results showed that the average population density of papaya mealybugs in the plantation was 120 individuals / 10 leaves, which significantly exceeded the intervention threshold of 100 individuals / 10 leaves, and some plants had already shown initial signs of damage such as leaf curling and honeydew contamination.

[0054] Accordingly, it was decided to immediately initiate the biocontrol method of this invention. First, in a standardized biological breeding facility, the hibiscus mealybug was propagated on the hibiscus host plant under the aforementioned breeding conditions (temperature 27±1°C, humidity 70±5%, photoperiod 14L:10D). On June 6th, a sufficient number of female adults with a body length between 2.5-3.5 mm and a distinctly swollen abdomen were collected. Subsequently, these female adults underwent physiological function restart treatment: they were subjected to 12 hours of starvation stress at 25°C and 60% RH, followed by 2 hours of refeeding on defatted cotton soaked in a 10% sucrose + 1% yeast extract solution to restore their vitality.

[0055] Based on the measured density of *Papaver rhoeas* mealybug (N_t = 120 mealybugs / 10 leaves) and the determined 1:1 inoculation ratio, the target inoculation density (N_c) for *Hibiscus mealybugs* should also be calculated to be 120 mealybugs / 10 leaves. Activated female adults were gently mixed with a carrier powder with a particle size of 50-100 micrometers, prepared by mixing 90% potato starch, 8% sodium alginate, and 2% L-serine, at a weight ratio of 1:30 in a rolling mixer.

[0056] On the afternoon of June 7, 2024, under clear and windless weather conditions, operators used portable electrostatic powder spraying equipment (set voltage +30kV) to inoculate the entire 2-hectare papaya orchard. The operators maintained a spraying distance of approximately 50 centimeters and evenly sprayed the powder containing hibiscus mealybugs onto the canopy, stems, and young fruit surfaces of the papaya plants.

[0057] Following inoculation, the population density of the two mealybug species in the park was continuously monitored on day 0 (before inoculation), day 7, day 14, day 21, and day 28.

[0058] Comparative Example 1

[0059] Another papaya orchard with similar conditions in the same area (initial papaya mealybug density of 120 insects / 10 leaves) was selected as a control, and conventional chemical pesticides were used for control. A 22.4% spirotetramat suspension, diluted to the recommended concentration of 2000 times, was sprayed throughout the orchard for the first time on June 7th, and a second spray was carried out 10 days later on June 17th. The papaya mealybug population density in this control area was monitored at the same time points (days 0, 7, 14, 21, and 28).

[0060] Comparative Example 2

[0061] Another papaya orchard with similar conditions in the same area (initial papaya mealybug density of 120 insects / 10 leaves) was selected as a control, and the traditional method of releasing predatory natural enemies was adopted. On June 7, adult Monterey ladybugs (Cryptolaemus montrouzieri) were released into the orchard at a density of 10 insects per tree. The papaya mealybug population density in this control area was monitored at the same time points (days 0, 7, 14, 21, and 28).

[0062] The monitoring data of Example 1 and Comparative Examples 1-2 are summarized in the table below:

[0063] Table 1

[0064] The data in the table above clearly shows that, in Example 1 of this invention, the population density of the papaya mealybug decreased by 62.5% on the 7th day after inoculation, demonstrating an extremely rapid suppression rate. By the 14th day, the reduction rate reached 87.5%, exceeding the 85% control success standard, and by the 21st day, it reached an excellent control level of 95.8%. Simultaneously, the population of the hibiscus mealybug, acting as a competitor, began to decline significantly after the 21st day, and by the 35th day, it had essentially disappeared from the field, verifying the safety of its self-extinction.

[0065] In contrast, while chemical control in Comparative Example 1 showed some initial effectiveness, the population density began to rebound after day 21 due to the killing of natural enemies and the development of pest resistance. By day 35, it had rebounded to 71 insects per 10 leaves, reaching over 70% of the intervention threshold. In Comparative Example 2, the traditional natural enemy control method, because natural enemies need time to adapt to the environment and reproduce, had a very slow effect on population control, only showing a noticeable suppressive effect after 21 days, far slower than the method described in this invention.

[0066] In summary, the method disclosed in this invention, which utilizes interspecific competition among *Hibiscus mealybug* species to exclude *Papaver rhamnoides* populations, achieves rapid, efficient, long-lasting, and ecologically safe control of the target pest through in-depth utilization of the competition mechanism and engineering design of the entire process. Its comprehensive effect is significantly better than existing chemical and biological control methods, and it has extremely high practical application value and promotion prospects.

Claims

1. A method for controlling the population of *Papaver rhoeas* by using interspecific competition among *Papaver somnifera* mealybugs, characterized in that, The method includes the following steps: S1. Preparation of targeted competitive biocontrol agents: Select the hibiscus mealybug, which does not have host adaptability to the host plant papaya and cannot complete its life cycle on papaya, and perform physiological function restart treatment on it to enhance its short-term competitive activity. The physiological function restarting treatment for the hibiscus mealybug specifically includes two phases executed sequentially: (1) The first stage is the starvation stress stage: The collected female adult hibiscus mealybugs were placed in a sealed container without host plants and lined with dry filter paper. Under the environmental conditions of 25 degrees Celsius and 60% relative humidity, they were subjected to continuous starvation treatment for 12 hours to interrupt the nutrient supply and activate their later feeding behavior. (2) The second stage is the refeeding vitality response stage: female adults subjected to hunger stress are transferred to a new container with a bottom of absorbent cotton soaked in refeeding vitality response solution. The female adults are placed in this environment for 2 hours so that they can eat a small amount to restore their strength and further enhance their feeding behavior. S2. Quantitative assessment of the population density of the target pest: In the target field, a systematic sampling survey and quantitative assessment of the population density of the papaya mealybug parasitizing the papaya plants was conducted to determine whether the threshold for initiating intervention was reached. The population density of *Papaver somniferum* was quantitatively assessed using a random sampling method, which included: (1) Randomly select 10 papaya leaves in the target field using the diagonal method, selecting mature leaves that are fully unfolded in the upper part of the canopy, with the back side as the inspection area; (2) For each sample plant, select the third fully unfolded leaf from the top of the canopy downwards; (3) Use a 1 cm² grid transparent calibration sheet to cover the pest gathering area on the back of the leaf, count the total number of nymphs and adults of Papaya mealybug in the grid, check 3 random 1 cm² areas on each leaf, take the average value as the pest density head / cm² of the leaf, summarize the density data of 10 leaves, calculate the average number of insects per leaf, and then convert it into the total number of insects per 10 leaves, which is the average population density in the field. (4) The action threshold for initiating intervention determined by this method is: when the average population density in the field exceeds 100 heads / 10 leaves, the subsequent inoculation steps are initiated. S3. Determination and Implementation of Inoculation Program: Based on the population density of Papaya Mealybug assessed in S2, the inoculation dose of Hibiscus Mealybug was accurately calculated using a pre-set competitive pressure index model. After mixing Hibiscus Mealybug with a micro-powdered synergistic carrier, the carrier was positively charged using an electrostatic powdering device and inoculated onto the papaya plants using electrostatic attraction. This created a resource dominance against Papaya Mealybug in the local ecological niche of the papaya plants, achieving rapid competitive exclusion and suppression of the Papaya Mealybug population. The step of accurately calculating the inoculation dose of hibiscus mealybug using a preset competitive pressure index model is defined by the competitive pressure index, namely CPI, as follows: CPI = (N_c × V_c × I_f) / (N_t × V_t). Wherein, N_c is the planned number of hibiscus mealybugs to be inoculated on every 10 leaves; N_t is the actual number of papaya mealybugs per unit area measured in S2; V_c is the colonization vigor coefficient of hibiscus mealybugs after physiological function restart treatment, and its value is set to 1.4; V_t is the conservation vigor coefficient of papaya mealybugs under natural field conditions, and its baseline value is set to 1.0; I_f is the interspecific interference coefficient, and its value is set to 1.2; Furthermore, in order to achieve rapid suppression of the papaya mealybug population, the CPI value calculated according to the formula is set to be greater than 1.5, and based on this, the ratio of the number of hibiscus mealybugs N_c to the number of papaya mealybugs N_t measured on site needs to be greater than 0.

89.

2. The method according to claim 1, characterized in that, The preparation of the targeted competitive biocontrol agent further includes standardized breeding of the hibiscus mealybug prior to physiological function restart treatment. Standardized breeding includes: (1) In an insect rearing cage with controlled environmental parameters, potted hibiscus was used as the host plant, and the ancestral population of hibiscus mealybug was inoculated and allowed to reproduce and expand naturally. (2) When the population density of the hibiscus mealybug reaches the preset collection threshold of more than 50 individuals per square centimeter of leaf area, collection shall be carried out; (3) The collection operation is specifically limited to collecting female adult insects that are pregnant with eggs. The morphological characteristics of female adult insects are that their bodies are covered with white wax powder, their body length reaches 2.5 mm to 3.5 mm, and their abdomen is obviously bulging.

3. The method according to claim 2, characterized in that, The environmental parameters maintained inside the insect rearing cage are: (1) The temperature is controlled at 27 degrees Celsius, with a fluctuation range not exceeding ±1 degree Celsius; (2) The relative humidity is maintained at 70% by an ultrasonic atomization humidification system, with fluctuations controlled within ±5%. (3) The photoperiod is set to a 14-hour light cycle and a 10-hour dark cycle using full-spectrum LED plant growth lights.

4. The method according to claim 1, characterized in that, The refeeding vitality response solution, by weight percentage, comprises: 10% sucrose as a high-energy carbon source; 1% yeast extract powder to provide B vitamins, amino acids, and trace elements; and 89% deionized water. After completing the refeeding vitality response phase, female adults undergo a secondary screening process, with weak or dead individuals being physically removed by touch to ensure that the targeted competitive biocontrol agent used for field release possesses high physiological activity and behavioral consistency.

5. The method according to claim 1, characterized in that, Precise inoculation is achieved using an enhanced carrier delivery system based on the principle of electrostatic adsorption, specifically including: (1) The female adult mealybug of hibiscus that has undergone physiological function restart treatment is gently mixed with a micro powdered synergistic carrier at a weight ratio of 1:30 to form a carrier-mealybug complex. (2) A portable electrostatic powder spraying device is used for inoculation. A high-voltage corona discharge needle is installed at the powder outlet of the device to make the carrier-mealyptus complex carry a positive charge when it is sprayed out. (3) By utilizing the negative charge on the surface of plant leaves and stems, positively charged complexes are firmly adsorbed onto the surface of papaya plants through electrostatic attraction.

6. The method according to claim 5, characterized in that, The synergistic carrier is a homogeneous powder composed of biocompatible materials with an average particle size of 50 to 100 micrometers, and its components, on a dry weight basis, include: (1) 90% potato starch, as the main skeleton; (2) 8% sodium alginate, as a humectant and adhesion enhancer; (3) 2% L-serine, as a short-term nutritional supplement and feeding inducer.

7. The method according to claim 1, characterized in that, The method further includes a synergistic step: (1) After suppressing the population density of Papaya Mealybug to a preset low level of less than 2 heads / 10 leaves, a clean environment without chemical pesticide residues was formed in the field. At this time, a small number of obligate parasitic wasps of Papaya Mealybug were selectively released into the field. (2) By utilizing the high clearance efficiency of natural enemy insects in low pest population environments, the remaining papaya mealybugs can be cleared and a self-sustaining, long-term stable low-density regulation ecological balance can be established, thereby achieving an organic combination of short-term rapid suppression and long-term stable control.