Will chemical pesticides lead to pest resistance? How to avoid it?
Chemical pesticides play an important role in the prevention and control of agricultural diseases, insect pests and weeds, but long-term use can easily lead to pest resistance, resulting in a decline in the prevention and control effect, and even endangering the sustainable development of agriculture. This article will comprehensively analyze the causes, common mechanisms, real cases and prevention and control strategies of resistance, and look forward to future development directions.
1. What is pest resistance?
Pesticide resistance refers to the fact that in the pest population, through natural selection and genetic variation, some individuals are less sensitive to a certain pesticide, resulting in a significant decrease in the effectiveness of the pesticide.
Long-term selection pressure from a single pesticide will cause the death of sensitive pest individuals, leaving only resistant individuals. After reproduction, the population as a whole tends to be resistant, forming resistance
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Result: The dosage of pesticides applied on the farm needs to be continuously increased, and the cost rises; alternating drugs have limited control failure.
2. The main mechanism of resistance formation
Pest resistance is usually generated in the following ways:
1. Genetic mutation changes the target site
After the pesticide target site mutates, the affinity decreases. For example, after the target protein of DDT-resistant fruit flies mutates, it is no longer affected by pesticides.
2. Enhanced expression of detoxification enzymes
Overexpression of metabolic enzymes (P450, GSTs, Esterase) in some pests can degrade pesticides faster.
3. Changes in behavior and crossing
Pests may avoid spraying areas or change their living habits to reduce the probability of exposure, thereby gradually acquiring resistance.
3. Real-life examples of resistance
For example, Colorado potato beetles have developed resistance to 52 different types of pesticides
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; If there is no "refuge area" in Bt cotton planting, cotton bollworms will quickly develop resistance to Bt toxins
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. This shows that without supporting management measures, resistance will occur rapidly and affect the duration of efficacy.
4. Adverse consequences of resistance
The prevention effect will decrease rapidly, and crops will suffer more serious damage;
Increase chemical dependence and cost burden;
Increase ecological risks: higher doses of pesticides may harm non-target organisms;
Sustainability will be damaged, affecting long-term farmland health.
Therefore, resistance management is a key task for sustainable agricultural development.
5. Comprehensive prevention and control strategy: how to delay or avoid resistance
1. Alternate use of pesticides with different mechanisms of action
According to the recommendations of EPA and IRAC, chemical substances with different mechanisms of action should be rotated to make it difficult for pests to acquire multiple resistances at the same time
irac-online.org.
Long-term recommendation: The same type of product cannot be used continuously for more than 2 generations.
2. Adopt the refuge strategy
Set up a non-spraying zone next to Bt crops to retain sensitive insect species and mate with resistant insects to dilute the resistance genes
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The United States requires 20–50% of Bt cotton to be set up in refuge areas, but China often has no regulations, and the risk of pesticide resistance is higher
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3. The best time to apply pesticides and precise application
By monitoring pest density and applying pesticides at the best stage, avoiding premature or delayed application, it will help improve the effect and reduce selection pressure
ipm.ucanr.edu.
4. Reduce the dose and use persistent products with caution
High-dose or long-lasting pesticides are counterproductive, and short-acting formulations that decompose quickly should be given priority.
5. Add biological control and non-chemical management
Release natural enemies or microbial pesticides;
Use trap crops or tillage measures;
These can reduce chemical pressure and protect resistant "sensitive insects"
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6. Monitoring-recording-evaluation
Regular inspections and detection of resistance changes;
Improve records and dynamically adjust pesticide use plans.
7. Farmer education and diffusion promotion
Farmers need male education to understand the mechanism of action and resistance risks; promote IPM concepts and reduce blind use
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6. Future direction: Technological innovation helps resistance management
AI-assisted pesticide design: For example, the Pesti-Gen model screens new pesticide structures with low toxicity through multi-objective optimization
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Gene and RNAi technology: Intervene resistance gene expression through gene editing or interference.
Microorganism or natural enemy combination: Bt, fungal agents, insect parasitic wasps work together to reduce resistance selection
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Intelligent monitoring and precision spraying: Use sensing, remote sensing and drone technology to achieve positioning spraying and real-time intervention.
VII. Summary
Long-term use of chemical pesticides does easily lead to pest resistance;
Resistance mechanisms include genetic mutations, increased metabolism, and behavioral changes;
Serious consequences, endangering agricultural stability;
Rotation, refuge areas, monitoring, biological control, and precision spraying should be comprehensively applied in the IPM system;
Technological innovation ensures agricultural product safety and environmental health while delaying resistance.
Resistance is not the inevitable fate of chemical pesticides. Through scientific management and innovative strategies, we can effectively extend the service life of pesticides and ensure sustainable agricultural development.
