Neonicotinoids

Neonicotinoids are a class of synthetic insecticides that are structurally similar to natural nicotinoids, which are active compounds found in tobacco plants. These insecticides are designed to affect the nervous system of insects, effectively controlling populations of pests such as aphids, whiteflies, mites, and others. Neonicotinoids are widely used in agriculture, horticulture, and urban landscaping to protect crops and ornamental plants.

Goals and importance of use in agriculture and horticulture

The primary goal of using neonicotinoids is to provide effective protection for plants against various insect pests, which helps increase yields and reduce product losses. In agriculture, neonicotinoids are applied to treat cereal crops, vegetables, fruit trees, and other agricultural plants. In horticulture, they are used to protect ornamental plants and shrubs, preventing damage to leaves, stems, and fruits. Due to their systemic nature, neonicotinoids penetrate plant tissues, providing long-lasting protection from pests.

Relevance of the topic

The study and proper application of neonicotinoids is an important aspect of modern agriculture and horticulture. The growing global population and increasing demand for food require effective methods of plant protection against pests. However, excessive and uncontrolled use of neonicotinoids has led to environmental issues such as declines in beneficial insect populations, including bees, and the development of pest resistance. Therefore, it is important to investigate the mechanisms of action of neonicotinoids, their environmental impact, and develop sustainable application methods.

History

• History of neonicotinoids

Neonicotinoids are a group of insecticides developed in the late 20th century that quickly gained popularity due to their high efficacy against insect pests. These products are synthetic analogs of nicotine, which affect the nervous system of insects. The history of neonicotinoids is closely tied to the development of chemical science and the pursuit of creating more effective and safer plant protection agents.

• Early research and discoveries

Neonicotinoids were developed as an extension of research conducted in the 1970s when scientists began studying chemicals with properties similar to nicotine but with improved characteristics for combating insect pests. Nicotine was known as an effective insecticide as early as the 19th century, but its use was limited due to high toxicity and instability. In the 1980s, scientists began looking for safer and more stable analogs that could have a prolonged effect and be less harmful to the environment.

• Development of the first neonicotinoids

The first neonicotinoids were synthesized in the 1980s. In 1990, the company sygenta (then novartis) launched the first commercially successful neonicotinoid — imidacloprid. This product was revolutionary because it proved to be much more effective against a range of pests, including aphids, the colorado potato beetle, and others, compared to traditional insecticides. Imidacloprid quickly became widely used in agriculture to protect both crops and plants in gardens and lawns.

• Expansion of use

In the following decades, other companies began developing new neonicotinoids such as thiamethoxam, actara, clothianidin, and others. These products quickly gained popularity in the market due to their high efficiency and long-lasting effects. They became key insecticides for fighting a variety of pests, such as aphids, the colorado potato beetle, corn beetles, thrips, and many other insect pests. Neonicotinoids were used in various industries, from agriculture and horticulture to protecting human health (e.g., for preventing insect-borne diseases).

• Safety and environmental issues

However, since the late 1990s, the use of neonicotinoids has raised serious environmental and toxicological concerns. In the early years of their use, they did indeed show high efficacy and minimal environmental impact. But over time, side effects, particularly on beneficial insects such as bees, began to emerge. Many studies have linked the use of neonicotinoids to massive bee die-offs, leading to widespread discussions about their safety.

Furthermore, neonicotinoids began causing resistance in some pests, reducing their effectiveness.

• Restrictions and bans

In response to growing concerns about the safety of neonicotinoids and their impact on bees and other beneficial organisms, the european union introduced restrictions on their use for treating crops that attract bees in 2013. In 2018, these restrictions were expanded to include a ban on the use of the three most popular neonicotinoids (imidacloprid, thiamethoxam, and clothianidin) in open fields.
Nevertheless, despite these restrictions, neonicotinoids continue to be used in some countries, and their development remains an important area in chemical plant protection.

• Modern approaches and the future of neonicotinoids

In recent years, efforts to develop safer formulations and innovative methods of using neonicotinoids have continued. Scientists and specialists are working on creating products with reduced impact on beneficial insects, such as bees and other predatory insects. At the same time, there is growing interest in integrated pest management approaches that combine chemical, biological, and agronomic methods.

Thus, the history of neonicotinoids is an example of a journey from successful discoveries and revolutionary technologies to the recognition of environmental risks and the development of new, safer methods of plant protection.

Classification

Neonicotinoids are classified based on chemical composition, mechanism of action, and spectrum of activity. The main groups of neonicotinoids include:

• Imidacloprid: one of the most common representatives, effective against aphids, whiteflies, mites, and other pests.
• Thiamethoxam: known for its high efficacy and low toxicity to mammals, used for protecting cereal crops.
• Clothianidin: used in the protection of vegetable and fruit crops, with high resistance to degradation in soil.
• Acetamiprid: effective against a wide range of insect pests, including beetles and thrips.
• Nectarine: used for controlling aphids and whiteflies, with low toxicity to beneficial insects.

Neonicotinoids are classified based on their chemical structure, mechanism of action, and application. Let's look at several main categories of neonicotinoids:

Classification by chemical structure

Based on the chemical structure, neonicotinoids are divided into several groups, each characterized by different synthesis features and effects on target organisms.

• Nicotinoid compounds with a chloropyrimidine base: this group of neonicotinoids contains chloropyrimidine in their structure. They are effective against a wide range of pests, including aphids, weevils, and other agricultural pests.
  Example: thiamethoxam — one of the widely used neonicotinoids with a chloropyrimidine base.
• Nicotinoid compounds with a neonicotinyllpyridine base: this group contains a pyridine ring in the active substance, distinguishing them from other neonicotinoids. These compounds are effective against a wide range of insect pests.
  Example: imidacloprid — a well-known neonicotinoid with a neonicotinyllpyridine base, widely used for pest control.
• Nicotinoid compounds with a thiazole base: thiazole compounds have their specific molecular structure, allowing them to accumulate in plant tissues and provide long-lasting effects.
  Example: acetamiprid — one of the compounds in this group, used to protect plants from various pests.

Classification by mode of action

Neonicotinoids can also be classified based on their action on insect organisms. They affect the nervous system by influencing the transmission of nerve impulses.

• Contact neonicotinoids: these compounds act upon direct contact with insects. After coming into contact with the insect’s body, the compound penetrates the organism and disrupts the functioning of the nervous system.
  Example: flonicamid — a neonicotinoid acting upon contact with pests, blocking nerve impulse transmission.
• Systemic neonicotinoids: these compounds have the ability to penetrate plant tissues, spread through them, and provide protection even against insects that feed on plant sap.
  Example: thiamethoxam and imidacloprid — both of these compounds have systemic action and can be applied to seeds to provide protection from the very beginning of plant growth.

Classification by area of application

Neonicotinoids can also be classified based on their areas of application, depending on the type of crops and pests they target.

• Neonicotinoids for agricultural crop protection: these compounds are used to combat pests that damage agricultural crops. They are effective against a wide range of insect pests, such as aphids, thrips, whiteflies, and many others.
  Example: imidacloprid — commonly used for protecting crops such as corn, rice, vegetables, and fruits.
• Neonicotinoids for protecting ornamental plants: these compounds are used to protect ornamental plants from pests such as spider mites and aphids.
  Example: acetamiprid — used to combat pests on ornamental plants such as roses and shrubs.
• Neonicotinoids for protection against disease-carrying insects: this group of compounds is also used to protect plants from insects that can carry various diseases, such as viruses or fungi.
  Example: thiamethoxam — used to protect agricultural plants from pests such as aphids and other insects that may transmit pathogens.

Classification by toxicity and resistance

Neonicotinoids can also be classified by their toxicity levels and the ability to accumulate in plants, which affects their persistence in the ecosystem.

• Highly toxic neonicotinoids: these compounds are highly toxic to insects and use minimal dosages for effective pest control.
  Example: imidacloprid — highly toxic and effectively destroys various insect pests at minimal doses.
• Low toxicity neonicotinoids: these compounds have lower toxicity but are still effective in combating insects. They can be used in areas where a safer approach to pest control is needed.
  Example: acetamiprid — relatively less toxic compared to other neonicotinoids, making it preferable for use in certain fields.

Mechanism of action

• How insecticides affect the insect nervous system

Neonicotinoids affect the insect nervous system by binding to nicotine acetylcholine receptors in nerve cells. This causes continuous excitation of nerve impulses, leading to paralysis and death of the insects. Unlike previous classes of insecticides, neonicotinoids have high selectivity for insects, reducing their toxicity to mammals and other invertebrates.

• Impact on insect metabolism

Neonicotinoids disrupt metabolic processes in insects, leading to decreased activity, reproduction, and survival. Inhibition of nerve signal transmission hinders essential functions such as feeding, movement, and reproduction.

• Examples of molecular mechanisms of action

Some neonicotinoids, such as imidacloprid, bind to nicotine acetylcholine receptors, causing constant excitation of nerve cells. Others, such as thiamethoxam, block ion channels, disrupting nerve signal transmission. These mechanisms ensure high efficacy against insect pests.

• Difference between contact and systemic effects

Neonicotinoids have systemic action, meaning they penetrate plant tissues and spread throughout all parts, including leaves, stems, and roots. This provides long-term protection for the plant and effectively controls pests feeding on various plant parts. Contact action is also possible, but their main effectiveness is associated with systemic distribution.

Examples of products from this group

• Imidacloprid
  mechanism of action: binds to nicotine acetylcholine receptors, causing continuous excitation of nerve cells.
  Examples of products:
  • Actara
  • Klordor
  • Lanergil

Advantages and disadvantages
advantages: broad spectrum of action, systemic distribution, low toxicity to mammals.
Disadvantages: toxicity to bees and other pollinators, potential resistance development in pests.

• Thiamethoxam
  mechanism of action: blocks ion channels, disrupting nerve signal transmission.
  Examples of products:
  • Belkar
  • Tyret
  • Redat

Advantages and disadvantages
advantages: high efficiency, low toxicity to beneficial insects, resistance to degradation.
Disadvantages: toxicity to bees if misapplied, potential accumulation in soil.

• Clothianidin
  mechanism of action: binds to acetylcholine receptors, causing insect paralysis.
  Examples of products:
  • Clofer
  • Cartimar
  • Necto

Advantages and disadvantages

Advantages: high resistance to degradation, systemic distribution, effective against a broad range of pests.
Disadvantages: toxicity to bees, potential contamination of water and soil.

Insecticides and their impact on the environment

• Impact on beneficial insects

Neonicotinoids have a significant impact on beneficial insects, including bees, wasps, and other pollinators. Bees are at risk of poisoning when collecting nectar and pollen from treated plants, leading to reduced populations and disruption of pollination processes. This negatively affects biodiversity and the productivity of crops reliant on pollination.

• Residual insecticide levels in soil, water, and plants

Neonicotinoids can remain in soil for extended periods, especially in humid and warm climates. They penetrate water through rainfall and irrigation, leading to contamination of water sources. In plants, neonicotinoids are distributed across all parts, including leaves, stems, and roots, providing systemic protection, but also potentially leading to accumulation in food products.

• Photostability and decomposition of insecticides in nature

Many neonicotinoids have high photostability, which increases their duration of action in the environment. This slows their decomposition under ultraviolet radiation and contributes to their accumulation in ecosystems. High resistance to degradation leads to the long-term presence of insecticides in soil and water, increasing the risk of toxicity to invertebrates and other organisms.

• Biomagnification and accumulation in food chains

Neonicotinoids have the potential for biomagnification, as they can accumulate in the bodies of insects and animals, moving up the food chain. This leads to increased concentrations of insecticides in predators and higher levels of the food chain, including humans. Biomagnification of neonicotinoids causes serious ecological and health issues, as accumulated insecticides can cause chronic poisoning and health disorders in animals and humans.

The problem of pest resistance to insecticides

• Causes of resistance development

The development of resistance in insect pests to neonicotinoids is due to genetic mutations and the selection of resistant individuals with repeated use of the same insecticide. Frequent and uncontrolled use of neonicotinoids promotes rapid resistance development, reducing their effectiveness and requiring the use of stronger and more toxic agents.

• Examples of resistant pests

Resistance to neonicotinoids has been observed in various insect pests, including whiteflies, aphids, mites, and some species of moths. These pests show decreased sensitivity to insecticides, making them harder to control and leading to the need for more expensive and dangerous chemicals.

• Methods to prevent resistance

To prevent resistance, it is necessary to rotate insecticides with different mechanisms of action, combine chemical and biological control methods, and use integrated pest management strategies. It is also important to follow recommended dosages and application schedules to avoid selecting resistant individuals and ensure the long-term effectiveness of products.

Safe use of insecticides

• Preparation of solutions and dosages

Proper preparation of solutions and accurate dosing of insecticides is critical for effective and safe use. Strictly follow the manufacturer's instructions to avoid overdose and inadequate plant treatment. Using measuring tools and

Quality water helps ensure the accuracy of dosing and effective treatment.

• Use of protective equipment when handling insecticides

When working with neonicotinoids, appropriate protective equipment such as gloves, masks, goggles, and protective clothing should be used. This helps prevent contact with insecticides on the skin, eyes, and respiratory system, reducing the risk of poisoning and negative health effects.

• Recommendations for treating plants

Treat plants during early morning or late evening hours to minimize impact on pollinators like bees. Avoid treatment in hot and windy weather, as this can lead to the spraying of insecticides onto beneficial plants and organisms. Also, consider the plant's growth stage, avoiding treatment during active flowering and fruiting.

• Adhering to waiting periods before harvest

Following recommended waiting periods before harvest after insecticide application ensures the safety of food products and prevents the accumulation of chemical residues in food. Adhering to waiting periods guarantees the safety of consumption and prevents health risks.

Alternatives to chemical insecticides

• Biological insecticides

Using entomophages, bacterial, and fungal agents is an environmentally safe alternative to chemical insecticides. Biological insecticides, such as bacillus thuringiensis, effectively combat insect pests without harming beneficial organisms and the environment.

• Natural insecticides

Natural insecticides such as neem oil, tobacco infusions, and garlic solutions are safe for plants and the environment for pest control. These methods have repellent and insecticidal properties, effectively controlling insect populations without using 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 destroy insect pests, reducing their population and preventing their spread. Other mechanical methods, such as sticky traps and barriers, also help control pest populations without the use of chemicals. These methods are effective and environmentally safe ways to manage pests.

Examples of popular insecticides from this group

Product name	Active ingredient	Mechanism of action	Application area
Imidacloprid	Imidacloprid	Binding to nicotine acetylcholine receptors, causing paralysis and death	Vegetable crops, cereals, fruit trees
Thiamethoxam	Thiamethoxam	Blocking ion channels, disrupting nerve signal transmission	Cereal crops, vegetables, fruit-bearing plants
Clothianidin	Clothianidin	Binding to acetylcholine receptors, causing insect paralysis	Vegetable and fruit crops, ornamental plants
Acetamiprid	Acetamiprid	Binding to nicotine acetylcholine receptors, causing continuous nerve excitation	Vegetables, cereals, and ornamental crops
Nectarine	Nectarine	Binding to nicotine acetylcholine receptors, causing paralysis and death	Vegetable and ornamental crops, fruit trees

Advantages and disadvantages

Advantages

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

Disadvantages

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

Risks and precautions

• Impact on human and animal health

Neonicotinoids can have a significant impact on human and animal health if used improperly. When absorbed into the human body, they can cause symptoms of poisoning, such as dizziness, nausea, vomiting, headaches, and in extreme cases, seizures and loss of consciousness. Animals, particularly pets, are also at risk of poisoning if insecticides come into contact with their skin or if they ingest treated plants.

• Symptoms of insecticide poisoning

Symptoms of neonicotinoid poisoning include dizziness, headaches, nausea, vomiting, weakness, difficulty breathing, seizures, and loss of consciousness. If insecticide contacts the eyes or skin, irritation, redness, and burning sensations may occur. If ingested, immediate medical attention should be sought.

• First aid for poisoning

In case of suspected poisoning with neonicotinoids, stop contact with the insecticide immediately, rinse 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, call emergency services and follow first aid instructions provided on the product packaging.

Pest prevention

• Alternative pest control methods

Using cultural methods such as crop rotation, mulching, removal of infected plants, and the introduction of resistant varieties helps prevent pest outbreaks and reduce the need for insecticides. Biological control methods, including using entomophages and other natural enemies of insect pests, are also effective.

• Creating unfavorable conditions for pests

Proper irrigation, removing fallen leaves and plant debris, maintaining garden cleanliness, and setting up physical barriers such as nets and borders help prevent pest infestations. Regularly inspecting plants and promptly removing damaged parts reduces plant attractiveness to pests.

Conclusion

The rational use of neonicotinoids plays a crucial role in protecting plants and increasing the yields of agricultural and ornamental plants. However, safety regulations must be followed and insecticides should be applied considering environmental factors to minimize their negative impact on the environment and beneficial organisms. An integrated pest management approach, combining chemical, biological, and cultural methods, promotes sustainable agricultural practices and biodiversity preservation.

Frequently asked questions (FAQ)

What are neonicotinoids and what are they used for?
Neonicotinoids 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.

How do neonicotinoids affect the insect nervous system?
Neonicotinoids bind to nicotine acetylcholine receptors in the insect nervous system, causing continuous excitation of nerve cells. This leads to paralysis and death of the insects.

What are the main groups of neonicotinoids?
The main groups of neonicotinoids include imidacloprid, thiamethoxam, clothianidin, acetamiprid, and nectar. Each of these groups has specific characteristics in its mechanism of action and application area.

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

How can resistance to neonicotinoids in insects be prevented?
To prevent resistance, it is necessary to rotate insecticides with different mechanisms of action, combine chemical and biological control methods, and follow recommended dosages and application schedules.

What environmental problems are associated with neonicotinoid use?
The use of neonicotinoids leads to the decline of beneficial insect populations, soil and water contamination, and the accumulation of insecticides in food chains, causing significant environmental and health problems.

Can neonicotinoids be used in organic farming?
No, most neonicotinoids do not meet the requirements for organic farming due to their synthetic origin and negative impact on the environment and beneficial organisms.

How to apply neonicotinoids for maximum effectiveness?
Strictly follow the manufacturer's instructions on dosage and application schedules, treat plants during early or late hours, avoid treatment during pollinator activity, and ensure even distribution of the insecticide on plants.

Are there alternatives to neonicotinoids for pest control?
Yes, there are biological insecticides, natural remedies (neem oil, garlic solutions), pheromone traps, and mechanical control methods that can be used as alternatives to chemical insecticides.

Where can neonicotinoids be purchased?
Neonicotinoids are available in specialized agro-technical stores, online shops, and plant protection suppliers. Before purchasing, ensure the legality and safety of the products being used.