Whitefly is a common agricultural pest, belonging to the hemiptera family Whitefly. They are small, usually only 1-3 mm long, with a white or yellowish body and an oval or round appearance, so named for the white wax powder on their bodies. These seemingly insignificant insects have a unique way of attaching to plants, which can cause serious harm to plants.
The Relationship Between Biological Characteristics And Attachment Of Whitefly
1. Morphological structure and attachment
Body structure:The body structure of the whitefly provides a certain basis for its attachment to the plant. It has slender antennae, and many sensory organs are distributed on the antennae, which can help the whitefly sense changes in the surrounding environment, including smell, temperature, humidity and other information from the plant, so as to guide them to find the right plant to attach.
Its wings are usually translucent and have some flexibility. When whiteflies approach plants during flight, the wings help them adjust their attitude and orientation in order to accurately land on the surface of the plant. In addition, the legs of the whitefly are also a key structure in its attachment process. The legs are slender and flexible, with special structures at the ends that help them stand firm on plants.
Waxy layer:The surface of the whitefly’s body is covered with a waxy powder that serves a variety of functions. On the one hand, it can reduce the water loss of the whitefly body, so that it can maintain a better survival state under different environmental humidity conditions. On the other hand, during the attachment process, when the wax layer is in contact with the plant surface, it can increase the adhesion through physical adsorption and chemical interaction. For example, certain chemicals in the waxy layer may interact with the waxy or other organic components of the plant epidermis, allowing whitefly to attach more firmly to the plant.
2. Living habits and attachment preference
Breeding habit:Whiteflies are extremely fertile, which also affects their attachment behavior. Female whiteflies lay their eggs on suitable plants, choosing young leaves, young stems and other parts of the plant. These sites usually have young, tender tissue with a relatively thin epidermis, which is more conducive for whitefly eggs and nymphs to attach and obtain nutrients. During breeding, whiteflies congregates at these ideal spawning sites, forming large swarms that increase the density of their attachment to the plant.
Phototaxis and tenderness:Whiteflies have significant phototaxis, which makes them tend to attach to the upper leaves and branches of plants that are well-lit. Areas with sufficient light are usually more temperate, which is conducive to the activity and survival of whiteflies. At the same time, whiteflies are also tender, young leaves and young stems are like “food paradise” for them. These areas are rich in nutrients, the juice is more easily absorbed by the whitefly’s stinging mouthparts, and the surface texture and chemistry of young leaves and young stems may be more suitable for whitefly attachment.
The Way Whiteflies Find Plants
1. Passive diffusion
Air propagation:Airflow is one of the important ways of passive diffusion of whitefly. In nature, breezes, wind fields, etc. can carry whiteflies from one place to another. When whiteflies are in the adult stage, they may be blown up by air currents, moving in the direction of the currents. In the process, if they come across a suitable plant, they will try to attach to it. For example, in farmland, when there is air flow between adjacent fields, whiteflies can spread from an infected field to a nearby uninfected field via airflow, thus expanding their range and attachment.
Artificial transmission:Human activity has also helped whitefly spread to some extent. In agricultural production, the transportation and trading of seedlings, flowers, etc., may inadvertently carry whiteflies. For example, when transporting flowers from an area with whitefly infestation to another area, if not subjected to strict quarantine and treatment, whitefly will be brought along with the flowers to the new environment and attach to the plants in the new area. In addition, the use of agricultural tools and people moving between fields can also contribute to the spread and attachment of whiteflies.
2. Actively searching
Chemical signal recognition:Plants give off a variety of volatile chemicals that can be sensed by whiteflies as a signal. Whiteflies have specialized olfactory receptors on their antennae that recognize specific odors given off by plants. For example, certain plants release volatile organic compounds that attract whiteflies when they are damaged or at certain stages of growth. By sensing these chemical signals, whiteflies can actively fly in the direction of the plant, eventually finding and attaching to the plant.
Visual guidance:Although whitefly’s visual system is relatively simple, it can also help them find plants to some extent. They can recognize visual features such as shape and color of plants. In general, green plants are more prominent in the natural environment, and whiteflies can locate the general location of the plant through vision. In the process of approaching the plant, they combine other sensory information, such as chemical signals and air currents, to more accurately land on the surface of the plant to attach.
The Specific Process Of Whitefly Attachment To The Plant
1. Landing
Approach and deceleration:When the whitefly finds the target plant through various routes, it will begin to approach the plant. During the approach, the whitefly uses the vibrations of its wings to adjust its flight speed and attitude. It will gradually reduce its speed and prepare for landing. The wing’s special structure and flexible vibration mode allow the whitefly to achieve precise control when approaching the plant, avoiding missing the target due to excessive speed or injury due to collisions.
Select the landing site:Whiteflies conduct an initial assessment of plant surfaces before landing. It will choose the right landing site based on factors such as light, texture and humidity on the plant surface. In general, they prefer to choose places such as the upper surface of the leaves of the plant, near the veins of the leaves, or young stems. These sites may have more suitable physical and chemical conditions, such as structures near the veins of the leaves that provide better grasping points for whiteflies, while the upper surface of the leaves is usually well lit and at a suitable temperature.
2. Fixation and stability
Physical gripping:Once the whitefly lands, its legs kick in. The claws and bristles at the end of the legs of whiteflies are in close contact with the surface of the plant. Claws can hook tiny bumps or gaps in the plant surface, while bristles increase friction by increasing the area of contact with the plant surface. This physical grip allows the whitefly to remain stable on the plant, even when disturbed by slight external forces, such as the breeze or the swaying of the plant itself.
Chemical adhesion:In addition to physical adhesion, chemical adhesion is also an important mechanism by which whiteflies attach to plants. The waxy layer and secretions on the surface of the whitefly’s body contain a number of chemicals that have adhesive properties. These chemicals can chemically react or physically adsorb with the waxy, cuticle and other components of the plant epidermis. For example, proteins or polysaccharides in certain secretions may form hydrogen bonds or other weak interactions with the chemical components of the plant epidermis, further cementing whitefly attachment to the plant.
3. Long-term attachment and adaptation
Adjust attitude:For a period of time after successful attachment, whiteflies adjust their posture according to the actual situation on the plant surface and the surrounding environmental conditions. It may change the degree of bending of the legs, the Angle of tilt of the body, etc., to achieve the best attachment and survival state. For example, in a windy environment, whiteflies will try to lower their body height to bring themselves closer to the plant surface and reduce wind resistance.
Coping with environmental change:Plants undergo various environmental changes during growth, such as changes in temperature, humidity, and light, and whiteflies need to adapt to these changes in order to maintain long-term attachment. In high-temperature environments, whiteflies may reduce water loss by adjusting their physiological activities and utilizing the waxy layer of the body. When humidity changes, it can adapt by changing the nature of the secretion or adjusting the tightness of the attachment. In addition, as the plant grows and develops, the whitefly will also move to more suitable locations on the plant to continue to obtain nutrients and survive.
Prevention And Control Measures
1. Agricultural prevention and control
Reasonable close planting and pruning: When planting crops, maintain reasonable plant spacing, ensure good ventilation and light, reduce humidity, and create an environment that is not conducive to whitefly breeding. Trim the plant regularly, remove the branches and leaves with whitefly eggs or nymphs in time, and centrally destroy them to prevent their spread. For example, in orchards, pruning branches and improving ventilation in the tree canopy can effectively reduce the habitat and breeding sites of whiteflies.
Rotation and intercropping: Implement rotation system to avoid accumulation of whitefly caused by continuous cropping. Plant some plants that can repel whitefly or attract its natural enemies. For example, intercropping plants with special odors such as mint can repel whitefly to a certain extent; Or interplant some honey source, attract parasitic wasps and other whitefly natural enemies, use the mutual restriction between organisms to control the number of whitefly.
Clean the garden: Remove weeds, residues and fallen leaves from the garden in a timely manner, as these areas may become wintering grounds or breeding grounds for whiteflies. After harvest, the remaining plant tissue in the field should be completely removed to reduce the survival base of whitefly in the field.
2. Physical prevention and control
Yellow board trapping: Use the yellowish nature of whiteflies to hang yellow armyworm boards in the field. The height of the yellow board should be slightly higher than the top of the plant, generally hanging 30-40 pieces per mu. Check and replace the yellow board regularly, and when the yellow board is full of whiteflies, clean up or replace the new board in time to ensure the trapping effect.
Insect-proof net isolation: When growing seedlings or planting some crops with high economic value, insect-proof nets can be built. The aperture of the insect net should be smaller than the size of the whitefly, and the insect net of 40-60 mesh is generally selected. This effectively discourages the adult whitefly from flying into the field and reduces its chance of harming the crop.
High temperature stifling shed: In the greenhouse planting, you can choose to carry out high temperature stifling shed during the summer leisure period. First, the soil in the shed is turned deep, poured with water, and then closed the greenhouse, so that the temperature in the shed is raised to 60-70 ° C for 7-10 days. This high temperature environment can kill the remaining whiteflies and their eggs and nymphs in the soil and shed, reducing the risk of damage to the next season’s crop.
3. Biological control
Protection and release of natural enemies: there are many kinds of natural enemies of whiteflies, such as Formosa bees, lacewings, predator mites, etc. In the field, natural enemies can be protected by planting nectar plants and setting up habitats for natural enemies. It is also possible to breed and release natural enemies artificially, releasing them into the field at a certain proportion and at a certain interval. For example, the release of 15,000-20,000 Formosa bees per mu, every 7-10 days, and 3-4 consecutive releases can effectively control the number of whiteflies.
Use of biological agents: Some biological agents such as Bacillus thuringiensis, Beauveria bassiana, etc., have a certain control effect on whitefly. Biological agents can be diluted and sprayed according to the product instructions. These biological agents can cause disease and death by infecting whiteflies, and are environmentally friendly and not easy to develop resistance.
4. Chemical control
Chemical selection: Select chemical agents with high efficiency, low toxicity, low residue and safety to natural enemies. Such as 25% thiamethoxam water dispersible granule, 10% imidacloprid wettable powder, 2.5% cyfluthrin emulsion, etc. Different agents can be used alternately to prevent whitefly from developing resistance.
Timing and method of application: The effect of application is better in the peak period of whitefly nymphs. Spray evenly, focusing on the back of the leaves, where whiteflies tend to gather. At the same time, it is necessary to pay attention to the concentration and safety interval of the agent, and operate in strict accordance with the instructions for pesticide use to ensure the quality and environmental safety of agricultural products.
Prevention And Treatment Significance
1. Ensuring agricultural production
Whiteflies cause serious damage to many crops, such as cucumbers and tomatoes in vegetables, and citrus in fruits. Whiteflies suck a lot of plant juice, resulting in yellow leaves and wilt, affecting photosynthesis, weakening plant growth and reducing yield. In severe cases, it can even lead to plant death, resulting in no harvest. Controlling the quantity of whitefly through effective control measures can ensure the normal growth and development of crops, improve the yield and quality, and ensure the stable and sustainable development of agricultural production. For example, in vegetable growing areas, the successful control of whiteflies can increase the yield of vegetables by 20% to 30%, and the appearance and taste of fruits will also be significantly improved.
2. Maintaining ecological balance
Whiteflies are primary consumers in the ecosystem, and if their numbers get out of control, it can have a ripple effect on the entire ecological chain. On the one hand, a large number of whiteflies will consume a lot of plant resources, affecting plant diversity and community structure. On the other hand, excessive use of chemical pesticides to control whitefly will kill a large number of beneficial organisms, such as natural enemies insects, soil microorganisms, etc., and destroy the balance of the ecosystem. The use of comprehensive control measures, such as biological control, can not only control the number of whiteflies, but also protect other organisms in the ecosystem, maintain ecological balance, and promote the healthy and stable development of the ecosystem.
Conclusion
The attachment of whiteflies to plants is a complex and delicate process, which involves many aspects such as the biological characteristics of whiteflies themselves, the way of finding plants and the specific mechanism of attaching to plants. A deeper understanding of these elements is important for us to develop effective whitefly control strategies. Only by mastering the mystery of the interaction between whiteflies and plants can we better protect plants from whiteflies and ensure the healthy development of agricultural production and ecological environment.
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