Diamides

Diamides are a class of insecticides belonging to the chemical group of hybrid compounds. They are characterized by the presence of two amide groups in their molecular structure, which gives them high efficacy in combating various insect pests. Diamides are widely used in agriculture and horticulture to protect crops from a wide range of pests, including aphids, whiteflies, moths, and other insects that damage vegetable, fruit, and ornamental crops.

Goals and significance in agriculture and horticulture

The primary goal of using diamides is to effectively protect agricultural crops from insect pests, leading to increased yields and reduced product losses. In horticulture, diamides are used to protect ornamental plants, fruit trees, and shrubs from insect infestations, preserving their health and aesthetic appeal. Due to their high efficiency and selective action, diamides are an essential tool in integrated pest management, ensuring sustainable and productive agriculture.

Relevance of the topic

In the context of a growing global population and increasing food demands, effective pest management is critical. Proper study and application of diamide insecticides allow for minimizing pest damage, improving crop productivity, and reducing economic losses. However, excessive and uncontrolled use of diamides can lead to resistance in pests and negative ecological consequences, such as a decline in beneficial insect populations and environmental contamination. Therefore, it is important to investigate the mechanisms of action of diamides, their impact on ecosystems, and develop sustainable application methods.

The history of diamides

Diamides are a group of chemical compounds that include insecticides actively used in agriculture to combat various pests. Their development spans several decades, from the discovery of the first molecules to modern improvements in their application. Unlike other classes of insecticides, diamides possess a specific mechanism of action, making them particularly effective against certain pest species that are difficult to control.

1. Development of diamides
   diamides, as a class of chemicals, began development in the 2000s. They were originally obtained as a result of efforts by scientists seeking to create compounds that target specific molecules in insect cells. The main goal was to develop insecticides with high efficacy but low toxicity to humans, animals, and beneficial insects.
2. Breakthrough and first commercial insecticide
   the first commercially successful diamides were developed in 2008. These compounds exhibited high activity against a range of harmful insects, including beetles, moths, and other pests. They employed a new mechanism of action targeting specific receptors in the insect nervous system, effectively controlling them without harming other species.
3. Chlorantraniliprole is one of the first registered products in this group that became widely used in agriculture. Its action on insecticide receptors allowed control over a wide range of pests, making it very popular in the fight against beetles and other insects.
4. Popularization and use in agriculture
   as diamides developed and improved, they began to be widely used in agriculture in various regions of the world. Their main application is in protecting crops such as corn, cotton, vegetables, fruits, and other plants vulnerable to insect attacks. The unique feature of these products is their ability to block crucial molecules in the insect nervous system, leading to paralysis and death.
5. Resistance issues
   with the increasing use of diamides, signs of resistance began to emerge in some insect species. This led to the need for developing new products and methods to combat resistant pests. In response, scientists started working on improving formulations and creating hybrid solutions to counteract developing resistance.
6. Current trends
   today, diamides continue to be used in the agricultural sector to protect crops. Manufacturers are working on improving these products, minimizing their environmental impact, and enhancing their effectiveness. Given the development of resistance among pests, there is a growing focus on using integrated pest management methods, combining biological and mechanical techniques with chemical solutions.

Examples of products

• Flubendiamide (coragen): one of the most well-known products in the diamide group. It exerts a systemic action, effectively affecting the insect nervous system.
• Lufenuron (altacor): another important product used to combat a broad range of pests. It is highly selective toward insects and comparatively low in toxicity to non-target organisms.

Classification

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

• Fipronil: one of the most commonly used diamide insecticides, effective against a wide range of insect pests.
• Chlorfenapyr: used to combat aphids and whiteflies, it is highly effective and resistant to degradation.
• Pyrrolo-pyrrole derivatives: a group of diamides characterized by high insecticidal properties and low toxicity to mammals.
• Diflubenzuron: a specialized diamide effective against certain insect species, such as moths and beetles.
• Benzimidazoles: used for systemic protection of plants, providing long-lasting action and broad-spectrum control.

Each of these groups has unique properties and mechanisms of action, allowing them to be used in different conditions and for different crops. Diamides are classified based on factors such as chemical structure, mechanism of action, application area, and toxicity.

Mechanism of action

How insecticides affect the insect nervous system

• Diamides affect the insect nervous system by binding to sodium channels in nerve cells. This leads to continuous excitation of nerve impulses, causing paralysis and death. Unlike organophosphates, which inhibit acetylcholinesterase, diamides act directly on ion channels, providing a more selective and effective effect.

Impact on insect metabolism

• Disruption of nerve signal transmission leads to failure in metabolic processes in insects, such as feeding, reproduction, and movement. This reduces the activity and viability of pests, allowing effective control over their populations and preventing damage to plants.

Examples of molecular mechanisms of action

• Some diamides, such as fipronil, bind to sodium channels, causing continuous excitation of nerve cells. Others, like chlorfenapyr, can block specific ion channels, disrupting normal nerve impulse transmission. These molecular mechanisms ensure high efficacy against various insect pests.

Contact vs. Systemic action

• Diamides can have both contact and systemic action. Contact diamides work directly upon contact with insects, penetrating through the cuticle or respiratory pathways, causing paralysis and death on contact. Systemic diamides penetrate plant tissues and spread throughout all parts, providing long-lasting protection against pests that feed on various plant parts. Systemic action allows for pest control over a longer period and in broader application areas.

Examples of products in this group

Fipronil
mechanism of action
binds to sodium channels, causing continuous excitation of nerve impulses and paralysis of insects.
Examples of products

• Fipron
• Agrofip
• Control

Advantages and disadvantages
advantages: high effectiveness against a wide range of pests, systemic action, resistance to degradation.
Disadvantages: toxicity to beneficial insects, risk of developing resistance in pests, potential environmental contamination.

Chlorfenapyr
mechanism of action
blocks sodium channels, causing continuous excitation of nerve cells and paralysis.
Examples of products

• Chlorfen
• Agrochlor
• Fenazon

Advantages and disadvantages
advantages: high effectiveness against aphids and whiteflies, resistance to photodegradation, systemic distribution.
Disadvantages: toxicity to bees and other beneficial insects, potential soil and water contamination, development of resistance in pests.

Pyrrolo-pyrrole derivatives
mechanism of action
these compounds bind to sodium channels in the insect nervous system, causing continuous nerve cell excitation and paralysis.
Examples of products

• Pyrethron
• Agropyreth
• Pyrethrofree

Advantages and disadvantages
advantages: high insecticidal potential, low toxicity to mammals, broad-spectrum activity.
Disadvantages: toxicity to beneficial insects, risk of resistance development in pests, possible environmental contamination.

Diflubenzuron
mechanism of action
inhibits sodium channels, causing continuous excitation of nerve cells and paralysis.
Examples of products

• Difeno
• Phosforic
• Agrodifen

Advantages and disadvantages
advantages: high effectiveness against specific pest species, systemic action, resistance to degradation.
Disadvantages: limited spectrum of action, high toxicity to beneficial insects, potential soil and water contamination.

Insecticides and their impact on the environment

Impact on beneficial insects

• Diamides exert toxic effects on beneficial insects, including bees, wasps, and other pollinators, as well as predatory insects that naturally control pest populations. This leads to a reduction in biodiversity and disruption of ecosystem balance, which negatively affects agricultural productivity and biodiversity.

Residual amounts of insecticides in soil, water, and plants

• Diamides can accumulate in soil over extended periods, especially under high humidity and temperature conditions. This leads to contamination of water sources through runoff and infiltration. In plants, diamides distribute throughout all parts, including leaves, stems, and roots, providing systemic protection. However, this also results in pesticide accumulation in food products and soil, which may negatively impact human and animal health.

Photostability and degradation of insecticides in the environment

• Many diamides possess high photostability, which increases their environmental persistence. This prevents rapid degradation of insecticides under sunlight and promotes their accumulation in soil and aquatic ecosystems. High resistance to degradation makes it difficult to remove diamides from the environment, increasing the risk of exposure to non-target organisms.

Biomagnification and accumulation in food chains

• Diamides can accumulate in the bodies of insects and animals, passing through the food chain and causing biomagnification. This leads to increased concentrations of the pesticide at higher trophic levels, including predators and humans. Biomagnification of diamides creates serious ecological and health risks, as accumulated insecticides may cause 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 diamides is driven by genetic mutations and the selection of resistant individuals with repeated use of the insecticide. Frequent and uncontrolled use of diamides promotes the rapid spread of resistant genes in pest populations. Insufficient adherence to recommended dosages and application regimes also accelerates the resistance process, making the insecticide less effective.

Examples of resistant pests

• Resistance to diamides has been observed in various species of insect pests, including whiteflies, aphids, mites, and some moth species. These pests exhibit reduced sensitivity to insecticides, complicating pest control and leading to the necessity of using more expensive and toxic chemicals or switching to alternative control methods.

Methods to prevent resistance

• To prevent the development of resistance in insects to diamides, it is essential to rotate insecticides with different modes of action, combine chemical and biological control methods, and implement 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 the insecticides.

Safety rules for using insecticides

Preparation of solutions and dosages

• Proper preparation of solutions and accurate dosing of insecticides is crucial for the effective and safe application of diamides. It is necessary to strictly follow the manufacturer's instructions for solution preparation and dosing to avoid overdosing or insufficient treatment of plants. Using measuring tools and high-quality water helps ensure accurate dosing and effective treatment.

Use of protective equipment when handling insecticides

• When working with diamide insecticides, it is necessary to use appropriate protective equipment, such as gloves, masks, goggles, and protective clothing, to minimize the risk of pesticide exposure to the human body. Protective equipment helps prevent contact with the skin and mucous membranes, as well as inhalation of toxic pesticide vapors.

Recommendations for treating plants

• Treat plants with diamide insecticides in the early morning or evening hours to avoid affecting pollinators, such as bees. Avoid treatment during hot and windy weather, as this may lead to pesticide spray drift and contamination of beneficial plants and organisms. It is also recommended to consider the plant's growth stage, avoiding treatment during periods of active flowering and fruiting.

Compliance with waiting periods before harvest

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

Alternatives to chemical insecticides

Biological insecticides

• The use of entomophages, bacterial, and fungal products represents an environmentally safe alternative to chemical insecticides. Biological insecticides, such as bacillus thuringiensis, effectively combat insect pests without harming beneficial organisms or the environment. These methods contribute to sustainable pest management and the preservation of biodiversity.

Natural insecticides

• Natural insecticides, such as neem oil, tobacco infusions, and garlic solutions, are safe for plants and the environment. These substances have repellent and insecticidal properties, allowing effective control of 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 kill insect pests, reducing their population and preventing further spread. Other mechanical methods, such as sticky surface traps and barriers, also help control pest populations without the use of chemicals. These methods are effective and environmentally safe ways of managing pests.

Risks and precautions

Impact on human and animal health

• Diamides can have serious effects on human and animal health if misused. When absorbed by humans, they can cause symptoms of poisoning, such as dizziness, nausea, vomiting, headaches, and, in severe cases, seizures and unconsciousness. Animals, especially pets, are also at risk of poisoning if the insecticide comes into contact with their skin or is ingested from treated plants.

Insecticide poisoning symptoms

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

First aid for poisoning

• If poisoning from diamide insecticides is suspected, it is important to immediately stop contact with the pesticide, wash affected skin or eyes with plenty of water for at least 15 minutes. If inhaled, move to fresh air and seek medical help. In case of ingestion, emergency services should be contacted immediately, and the first aid instructions on the product's packaging should be followed.

Pest prevention

Alternative methods for pest control

• Cultural methods, such as crop rotation, mulching, removing infected plants, and using resistant varieties, help prevent pest infestation and reduce the need for insecticides. These methods contribute to creating unfavorable conditions for pest insects and strengthening plant health. Biological control methods, including the use of entomophages and other natural enemies of pests, are also effective preventative tools.

Creating unfavorable conditions for pests

• Providing proper irrigation, removing fallen leaves and plant debris, maintaining garden and orchard cleanliness helps create unfavorable conditions for the reproduction and spread of insect pests. Physical barriers, such as nets and borders, can prevent pests from accessing plants. Regular plant inspections and the timely removal of damaged parts also help reduce plant attraction to pests.

Conclusion

The rational use of diamides plays an important role in plant protection and increasing agricultural and ornamental crop yields. However, safety protocols must be followed, and environmental factors must be considered to minimize negative impacts on the environment and beneficial organisms. An integrated approach to pest management, combining chemical, biological, and cultural control methods, contributes to the sustainable development of agriculture and biodiversity preservation. Additionally, it is essential to continue research on the development of new insecticides and control methods aimed at reducing risks to human health and ecosystems.

Frequently asked questions (FAQ)

What are diamides and what are they used for?

• Diamides are a class of insecticides containing two amide groups in their molecular structure. They are used to protect plants from various insect pests, increasing yields and preventing damage to cultivated plants.

How do diamides affect the insect nervous system?

• Diamides bind to sodium channels in insect nerve cells, causing continuous excitation of nerve impulses. This leads to paralysis and death of pests.

Are diamides harmful to beneficial insects, such as bees?

• Yes, diamides are toxic to beneficial insects, including bees and wasps. Their application requires strict adherence to regulations to minimize the impact on beneficial insects.

How can resistance to diamide insecticides in insects be prevented?

• To prevent resistance, it is necessary to rotate insecticides with different modes of action, combine chemical and biological control methods, and adhere to recommended dosages and application schedules.

What environmental issues are associated with the use of diamides?

• The use of diamides leads to a reduction in beneficial insect populations, soil and water contamination, and accumulation of insecticides in food chains, causing serious ecological and health issues.

Can diamides be used in organic farming?

• No, diamides do not meet the requirements for organic farming due to their synthetic origin and potential negative effects on the environment and beneficial organisms.

How should diamides be applied for maximum effectiveness?

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

Are there alternatives to diamide insecticides for pest control?

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

How can the environmental impact of diamides be minimized?

• Use insecticides only when necessary, adhere to recommended dosages and application schedules, avoid pesticide runoff into water sources, and implement integrated pest management methods to reduce dependence on chemical solutions.

Where can diamides be purchased?

• Diamides are available at specialized agricultural stores, online retailers, and plant protection suppliers. Before purchasing, it is important to verify the legality and safety of the products.