Oxadiazines

Oxadiazines are a class of synthetic insecticides characterized by a structure containing an oxadiazine ring. These compounds are widely used in agriculture and horticulture to control various insect pests. Oxadiazines have a broad spectrum of activity and are effective against a wide range of pests, including aphids, whiteflies, mites, and other pests of vegetables, fruits, and ornamental crops.

Goals and importance of use in agriculture and horticulture

The main goal of using oxadiazines is to protect agricultural crops from insect pests, which helps increase yields and reduce product losses. In horticulture, oxadiazines are used to protect ornamental plants, fruit trees, and shrubs from insect attacks, maintaining their health and aesthetic appeal. Due to their high efficiency and systemic action, oxadiazines are an important tool in integrated pest management (ipm), providing sustainable and productive agriculture.

Relevance of the topic

In the context of the growing global population and increasing food demands, effective pest management has become critically important. Proper study and use of oxadiazines help minimize damage from pests, increasing agricultural productivity and reducing economic losses. However, excessive and uncontrolled use of oxadiazines can lead to resistance development in pests and negative environmental consequences. Therefore, it is important to study the mechanisms of action of oxadiazines, their impact on the environment, and develop sustainable methods of application.

History of oxadiazines

Oxadiazines are a relatively new group of insecticides that were developed in the 1990s. These chemical compounds attracted the attention of scientists due to their high efficacy in controlling insect pests and their relatively good ecological safety compared to older insecticides. Their history began with the development of new molecules that could effectively target the insect nervous system while having minimal toxic effects on humans, animals, and beneficial insects.

1. Development of the first oxadiazines

The first oxadiazines were synthesized in the early 1990s as part of research aimed at creating new classes of insecticides with high selectivity for pests and minimal impact on the ecosystem. Unlike other insecticides, such as pyrethroids or neonicotinoids, oxadiazines target insect nervous systems but are not highly toxic to humans and animals.

In 1996, basf developed the first commercial oxadiazine-based insecticide — acetamiprid. This product became popular due to its effectiveness against a wide range of pests, such as aphids, mealybugs, whiteflies, and other insects that damage agricultural crops and garden plants.

2. Expansion of oxadiazine use

After the introduction of acetamiprid, several other oxadiazine-based products appeared on the market. For example, metamiprid was developed in 2001 and became one of the popular insecticides for controlling pests like armored mites and whiteflies. These insecticides proved effective not only for protecting agricultural crops like soybeans, corn, tomatoes, potatoes, and citrus fruits but also for maintaining ornamental plants.

3. Advantages of oxadiazines

The main advantage of oxadiazines is their high specificity of action. These insecticides affect insects by disrupting their nervous system, blocking the transmission of nerve impulses, and causing paralysis. However, due to their high selectivity, they are less toxic to beneficial insects and other organisms, making them attractive for use in agriculture.

Additionally, oxadiazines have a long-lasting effect, reducing the need for frequent reapplications, and they are highly resistant to environmental factors such as sunlight and rain. These factors make oxadiazines an important tool in integrated pest management (ipm).

4. Environmental and ecological issues

Like all chemical insecticides, oxadiazines can cause environmental problems, especially if safe application guidelines are not followed. For example, they can be toxic to aquatic organisms if they enter water bodies. Additionally, despite their relative safety for bees and other beneficial insects, improper use and non-compliance with waiting periods before harvest can lead to negative consequences.

5. Current issues and the future of oxadiazines

Today, oxadiazines remain an important class of insecticides in pest control. However, like other chemical insecticides, there is a problem of insect resistance to these products. In response to this problem, scientists are developing new formulas, combining oxadiazines with other substances, or using them in conjunction with biological pest control methods.

Furthermore, growing interest in environmental safety encourages manufacturers to create less toxic products that will not harm ecosystems, including beneficial insects and animals.

Thus, the history of oxadiazines is a journey from innovative discoveries to their use in agriculture, with ongoing efforts to improve their safety and efficacy for both agriculture and ecology.

Resistance issues and innovations

The development of resistance in insects to oxadiazines has become one of the main challenges associated with their use. Pests that are repeatedly exposed to oxadiazines can evolve to become less susceptible to their effects. This requires the development of new insecticides with different modes of action and the implementation of resistant pest management methods, such as insecticide rotation and using combined formulations. Modern research focuses on creating oxadiazines with improved properties to reduce the risks of resistance development and minimize ecological impact.

Classification

Oxadiazines are classified according to various criteria, including chemical composition, mechanism of action, and spectrum of activity. The main groups of oxadiazines include:

• Fufenatin: one of the first oxadiazine compounds used in agriculture to control aphids and whiteflies.
• Busilatine: used to combat a wide range of insect pests, including aphids, whiteflies, and mites.
• Nicoabatine: a specialized oxadiazine effective against certain types of insects, such as moths.
• Serpentine: developed for systemic plant protection, providing long-lasting action and a broad spectrum of control.

Each of these groups has unique properties and mechanisms of action, making them suitable for use in different conditions and for various crops.

In this classification, oxadiazines can be divided by different characteristics, such as chemical structure, mechanism of action, application areas, and their impact on pests.

1. Classification by chemical structure

Oxadiazines are organic compounds that contain an oxadiazine ring in their molecular structure. Variants of oxadiazines may differ by subcategories depending on their specific chemical structure.

• Symmetric oxadiazines: these compounds have identical structures on both sides of the molecule. They are stable and generally have a long-lasting effect on pests. Example: acetamiprid — a product belonging to the symmetric oxadiazine group, widely used for protection against various pests.
• Asymmetric oxadiazines: these substances have differences in the molecular structure on both sides, allowing them to affect a broader range of insects. Example: thiamethoxam — an asymmetric oxadiazine that has strong activity against numerous insect pests and exhibits systemic activity.

2. Classification by mechanism of action

Oxadiazines act through the insect nervous system by interacting with receptors and ion channels involved in nerve impulse transmission. These compounds disrupt synaptic activity, leading to paralysis in insects. They can be classified by their type of impact on the nervous system.

• Contact insecticides: oxadiazines that have toxic effects upon contact with the insect. They quickly penetrate the insect’s body through its outer covering and block nerve activity. Example: acetamiprid — affects the nervous system through contact with the insect's body, effectively blocking their movement and viability.
• Systemic insecticides: these compounds can penetrate plant tissues and spread through its vascular system. This allows the product to affect pests, even if they are feeding on the plant sap. Example: thiamethoxam — widely used in agriculture for protection against pests like aphids and the colorado potato beetle due to its systemic activity.

3. Classification by application area

Oxadiazines are widely used in agriculture but may differ depending on the type of crops and pests they are used to control.

• Oxadiazines for vegetable and fruit crop protection: these insecticides are used to protect vegetables and fruits from insects that damage the fruits and leaves of plants. Example: thiamethoxam — used to protect various vegetable and fruit crops, such as tomatoes, potatoes, and apples.
• Oxadiazines for ornamental plant protection: these products are also used in horticulture to protect ornamental plants, such as roses, shrubs, and flowers, from insect pests. Example: acetamiprid — commonly used to protect ornamental plants in greenhouses and open areas.
• Oxadiazines for agricultural crop protection: these compounds are used to protect cereal crops, as well as combat pests on sugarcane and other crops. Example: thiamethoxam — actively used in agriculture to protect crops like corn and rice from pests.

4. Classification by toxicity

Oxadiazines can be classified according to their toxicity to insects as well as to other organisms, including beneficial insects and humans.

• Highly toxic oxadiazines: these products have high toxicity to pests, allowing for effective population control even at low doses. Example: thiamethoxam — highly toxic to insects and used to control various agricultural pests.
• Low toxicity oxadiazines: some oxadiazines have relatively low toxicity to beneficial insects and can be used in conditions where minimizing environmental impact is important. Example: acetamiprid — safer for beneficial insects, such as bees, and can be used in gardens and agricultural areas with minimal risk.

5. Classification by resistance to environmental factors

Oxadiazines can also be classified by their resistance to environmental factors such as light, temperature, and humidity.

• Light-resistant oxadiazines: these products have high resistance to photodegradation and maintain their effectiveness even when exposed to sunlight for extended periods. Example: thiamethoxam — exhibits good photostability and is effective in various climatic conditions.
• Light-unstable oxadiazines: some oxadiazines break down under sunlight and lose their effectiveness, which limits their use in intense sunlight conditions. Example: acetamiprid — less stable to light and may lose its activity under ultraviolet rays.

Mechanism of action

How insecticides affect the insect nervous system:

• Oxadiazines affect the insect nervous system by binding to nicotinic acetylcholine receptors in nerve cells. This causes continuous excitation of nerve impulses, leading to paralysis and death of the insect. Unlike organophosphates, which inhibit acetylcholinesterase, oxadiazines act directly on nerve channels, providing a more selective and effective impact.

Effect on insect metabolism

• Disruption of nerve signal transmission leads to a breakdown in the insect's metabolic processes, such as feeding, reproduction, and movement. This reduces the activity and viability of pests, aiding effective population control.

Examples of molecular mechanisms

• Some oxadiazines, such as fufenatin, bind to nicotinic acetylcholine receptors, causing continuous excitation of nerve cells. Others, like busilatine, may block certain ion channels, disrupting normal nerve impulse transmission. These molecular mechanisms provide high effectiveness of oxadiazines against various insect pests.

Difference between contact and systemic action

• Oxadiazines can have either contact or systemic action. Contact oxadiazines act directly when they come into contact with insects, penetrating through their cuticle or respiratory pathways. Systemic oxadiazines penetrate plant tissues and spread through the vascular system, providing long-term protection against pests feeding on different parts of the plant. Systemic action allows for pest control over a longer period and across larger areas of application.

Examples of products in this group

Fufenatin

• Mechanism of action: binds to nicotinic acetylcholine receptors, causing paralysis and death of insects.
• Examples of products: fufena, tifura, pestan.
• Advantages and disadvantages:
  • Advantages: high effectiveness against aphids and whiteflies, systemic action.
  • Disadvantages: toxicity to beneficial insects, potential resistance development in pests, environmental risk.

Busilatine

• Mechanism of action: blocks nerve impulses, causing paralysis and death of insects.
• Examples of products: busil, infen, akeron.
• Advantages and disadvantages:
  • Advantages: broad spectrum of action, systemic distribution, low toxicity to mammals.
  • Disadvantages: toxicity to bees and other pollinators, potential soil and water contamination, development of resistance in pests.

Nicoabatine

• Mechanism of action: binds to ion channels, disrupting the transmission of nerve impulses.
• Examples of products: nicoatrin, motofan, spiro.
• Advantages and disadvantages:
  • Advantages: high selectivity, effective against certain species of insects.
  • Disadvantages: limited spectrum of action, high cost, potential accumulation in the environment.

Serpentine

• Mechanism of action: binds to acetylcholinesterase, inhibiting it and disrupting the transmission of nerve impulses.
• Examples of products: serpen, activat, agroserpent.
• Advantages and disadvantages:
  • Advantages: long-lasting action, systemic distribution, effective against a wide range of pests.
  • Disadvantages: toxicity to beneficial insects, potential water and soil contamination, development of resistance in pests.

Insecticides and their impact on the environment

Impact on beneficial insects

• Oxadiazines have toxic effects on beneficial insects, including bees, wasps, and other pollinators, as well as predatory insects that naturally control pest populations. This leads to reduced biodiversity and disruption of ecosystem balance, which negatively impacts agricultural productivity and biodiversity.

Residues of insecticides in soil, water, and plants

• Oxadiazines can accumulate in the soil for long periods, especially under high humidity and temperature conditions. This leads to water pollution through runoff and infiltration. In plants, oxadiazines distribute throughout all parts, including leaves, stems, and roots, providing systemic protection but also leading to pesticide accumulation in food products and soil, which can negatively impact human and animal health.

Photostability and degradation of insecticides in nature

• Many oxadiazines have high photostability, which extends their effectiveness in the environment. This prevents rapid breakdown under sunlight and contributes to their accumulation in soil and aquatic ecosystems. The high resistance to degradation complicates the removal of oxadiazines from the environment and increases the risk of their impact on non-target organisms.

Biomagnification and accumulation in food chains

• Oxadiazines can accumulate in the bodies of insects and animals, moving up the food chain and causing biomagnification. This results in higher concentrations of insecticides at higher levels of the food chain, including predators and humans. Biomagnification of oxadiazines causes significant ecological and health problems, as accumulated insecticides can lead to chronic poisoning and health disorders in animals and humans.

The problem of insect resistance to insecticides

Causes of resistance development

• The development of resistance in insects to oxadiazines is caused by genetic mutations and the selection of resistant individuals through repeated use of the insecticide. Frequent and uncontrolled use of oxadiazines promotes the rapid spread of resistant genes among pest populations. Inadequate adherence to dosage and application schedules also accelerates the development of resistance, making the insecticide less effective.

Examples of resistant pests

• Resistance to oxadiazines has been observed in various insect species, including whiteflies, aphids, mites, and some moth species. These pests show reduced sensitivity to the insecticides, making them difficult to control and leading to the need for more expensive and toxic products or alternative control methods.

Methods to prevent resistance

• To prevent the development of resistance in insects to oxadiazines, it is necessary to use insecticide rotation with different mechanisms of action, combine chemical and biological control methods, and apply integrated pest management strategies. It is also important to follow recommended dosages and application schedules to avoid the selection of resistant individuals and maintain the effectiveness of the products in the long term.

Safety guidelines for insecticide use

Preparation of solutions and dosages

• Proper preparation of solutions and accurate dosing of insecticides are critical for the effective and safe use of oxadiazines. Strictly follow the manufacturer's instructions for preparing solutions and dosing to avoid overdosing or inadequate treatment of plants. Using measuring tools and high-quality water helps ensure accurate dosing and effective treatment.

Use of protective equipment when working with insecticides

• When working with oxadiazines, appropriate protective equipment such as gloves, masks, goggles, and protective clothing should be used to minimize the risk of exposure to the insecticide. Protective equipment helps prevent contact with the skin and mucous membranes and inhalation of toxic fumes.

Recommendations for plant treatment

• Treat plants with oxadiazines during the morning or evening hours to avoid affecting pollinators such as bees. Avoid treatment during hot and windy weather, as this may cause the insecticide to be sprayed onto beneficial plants and organisms. It is also recommended to consider the growth stage of the plants, avoiding treatment during active flowering and fruiting periods.

Waiting period before harvest

• Adhering to the recommended waiting periods before harvesting after the application of oxadiazines ensures the safety of food consumption and prevents pesticide residues from entering food products. It is important to follow the manufacturer's instructions regarding waiting periods to avoid poisoning risks and ensure product quality.

Alternatives to chemical insecticides

Biological insecticides

• Using entomophages, bacterial, and fungal preparations presents an environmentally safe alternative to chemical insecticides. Biological insecticides, such as bacillus thuringiensis, effectively control insect pests without harming beneficial organisms and the environment. These methods contribute to sustainable pest management and biodiversity conservation.

Natural insecticides

• Natural insecticides, such as neem oil, tobacco infusions, and garlic solutions, are safe for plants and the environment for pest control. These products have repellent and insecticidal properties, making them effective in controlling insect populations without synthetic chemicals. Natural insecticides can be used in combination with other methods for optimal results.

Pheromone traps and other mechanical methods

• Pheromone traps attract and kill insect pests, reducing their numbers and preventing spread. Other mechanical methods, such as sticky surface traps and barriers, also help control pest populations without using chemicals. These methods are effective and environmentally safe ways to manage pests.

Advantages and disadvantages

Advantages

• High effectiveness against a wide range of insect pests
• Systemic distribution in the plant, providing long-term protection
• Low toxicity to mammals compared to other insecticide classes
• High photostability, ensuring long-lasting action

Disadvantages

• Toxicity to beneficial insects, including bees and wasps
• Potential development of resistance in insect pests
• Potential contamination of soil and water sources
• High cost of some products compared to traditional insecticides

Risks and precautions

Impact on human and animal health

• Oxadiazines can have serious health effects on humans and animals if not used properly. If ingested, they can cause symptoms of poisoning such as dizziness, nausea, vomiting, headaches, and in extreme cases, seizures and loss of consciousness. Animals, especially pets, are also at risk of poisoning if the insecticide comes into contact with their skin or if they ingest treated plants.

Symptoms of insecticide poisoning

• Symptoms of oxadiazine poisoning include dizziness, headaches, nausea, vomiting, weakness, difficulty breathing, seizures, and loss of consciousness. If the insecticide comes into contact with the eyes or skin, irritation, redness, and burning may occur. In the case of ingestion, medical attention should be sought immediately.

First aid for poisoning

• If poisoning by oxadiazine is suspected, immediately cease contact with the insecticide, wash the affected skin or eyes with large amounts of water for at least 15 minutes. If inhaled, move to fresh air and seek medical help. In case of ingestion, emergency medical services should be called, and first aid instructions on the product packaging should be followed.

Pest prevention

Alternative pest control methods

• Cultural methods such as crop rotation, mulching, removal of infected plants, and introduction of resistant varieties help prevent pest emergence and reduce the need for insecticides. These methods create unfavorable conditions for pests and strengthen plant health. Biological control methods, including the use of entomophages and other natural insect predators, are also effective for pest prevention.

Creating unfavorable conditions for pests

• Proper watering, removal of fallen leaves and plant debris, and maintaining garden cleanliness help create unfavorable conditions for pest breeding and spread. Installing physical barriers, such as nets and borders, helps prevent pests from accessing plants. Regular plant inspection and timely removal of damaged parts further reduce plant attraction for pests.

Conclusion

The rational use of oxadiazines plays a key role in protecting plants and increasing the yield of agricultural and ornamental crops. However, safety guidelines must be followed, and environmental aspects must be considered to minimize their negative impact on the environment and beneficial organisms. An integrated pest management approach that combines chemical, biological, and cultural control methods promotes sustainable agriculture development and biodiversity conservation. It is also important to continue research on developing new insecticides and control methods aimed at reducing risks to human health and ecosystems.

Frequently asked questions (FAQ)

1. What are oxadiazines and what are they used for? 

Oxadiazines are a class of synthetic insecticides used to protect plants from various insect pests. They are widely used in agriculture and horticulture to increase yields and prevent plant damage.

2. How do oxadiazines affect the insect nervous system? 

Oxadiazines bind to nicotinic acetylcholine receptors in insect nerve cells, causing continuous excitation of nerve impulses. This leads to paralysis and death of the insect.

3. Can oxadiazines be used in greenhouses? 

Yes, oxadiazines are widely used in greenhouses to protect plants from pests. However, safety rules must be followed, appropriate protective gear should be used, and the manufacturer's instructions on dosage and application timing should be adhered to.

4. Are oxadiazines harmful to bees? 

Yes, oxadiazines are toxic to bees and other pollinators. Their use requires strict adherence to regulations to minimize their impact on beneficial insects.

5. How can insect resistance to oxadiazines be prevented? 

To prevent resistance, it is important to use insecticide rotation with different mechanisms of action, combine chemical and biological control methods, and follow recommended dosages and application schedules.

6. What environmental issues are associated with the use of oxadiazines? 

The use of oxadiazines can lead to a decline in beneficial insect populations, soil and water contamination, and pesticide accumulation in food chains, causing serious ecological and health problems.

7. Can oxadiazines be used in organic farming? 

No, oxadiazines do not meet the requirements of organic farming due to their synthetic origin and potential negative impact on the environment and beneficial organisms.

8. How should oxadiazines be applied for maximum effectiveness? 

It is important to strictly follow the manufacturer's instructions on dosage and application schedules, treat plants in the morning or evening hours, avoid treatment during pollinator activity, and ensure even distribution of the insecticide on plants.

9. Are there alternatives to oxadiazines for pest control? 

Yes, biological insecticides, natural remedies (neem oil, garlic solutions), pheromone traps, and mechanical control methods can be used as alternatives to oxadiazines.

10. Where can oxadiazines be purchased? 

Oxadiazines are available at specialized agronomy stores, through online retailers, and from plant protection suppliers. Before purchasing, ensure the products are legal and safe to use.