Application of copper oxide in crops

Bactericidal and disease-resistant mechanism of copper oxide
Copper oxide (CuO) is an inorganic copper compound, and its core function comes from the release and biological activity of copper ions. When copper oxide is applied to crops in the form of nanoparticles or micron-sized powder, copper ions (Cu²⁺) can work in the following ways:
Destroy pathogen cell structure: copper ions bind to thiol groups (-SH) and amino groups (-NH₂) in fungal or bacterial cell membranes, causing protein denaturation and cell membrane rupture, thereby killing pathogens.
Inhibit metabolic enzyme activity: copper ions interfere with the respiratory chain and enzyme system (such as dehydrogenase) of pathogens, hinder energy metabolism, and inhibit their reproduction.
Activate the plant immune system: copper oxide can induce plants to produce defense enzymes (such as peroxidase and phenylalanine ammonia lyase), and upregulate the expression of disease-resistant genes, thereby enhancing crop resistance to diseases.
Specific application cases of copper oxide in agriculture
1. Control of fungal diseases
Copper oxide has significant control effects on a variety of fungal diseases:
Tobacco black leg disease: Southwest University research shows that nano copper oxide (CuO NPs) can 100% inhibit the mycelial growth and spore germination of tobacco phytophthora by root irrigation, while activating the tobacco defense enzyme system, with a control effect of 33.69%.
Tomato early blight and cucumber downy mildew: Copper oxide preparations are sprayed at the early stage of the disease, and the continuous release of copper ions blocks the infection of pathogens, reduces the spread of lesions, and significantly reduces the risk of disease transmission.
2. Control of bacterial diseases
Citrus canker and pepper scab: Copper oxide destroys the bacterial cell wall structure, inhibits its division and toxin secretion, and maintains high bactericidal activity, especially in high humidity environments.
Vegetable soft rot: Copper ions penetrate into bacterial cells, interfere with DNA replication and protein synthesis, and reduce crop rot losses.
3. Pest control and ecological regulation
Inhibition of mites and scale insects: Copper oxide damages the wax layer on the insect surface through surface adsorption, causing dehydration and death, while reducing the hatching rate of insect eggs.
Soil nematode control: Nano copper oxide can change the structure of soil microbial communities, inhibit the activity of nematode larvae, and reduce insect population density.
Application advantages and technological innovation of copper oxide
Broad-spectrum and low drug resistance: Copper oxide is not easy to induce pathogens to develop drug resistance through a multi-point action mechanism, and is suitable for long-term disease management.
Nanotechnology improves efficiency: Nano copper oxide can achieve high-efficiency sterilization at low concentrations due to its large specific surface area and strong penetration, reducing copper residues and environmental pollution.
Environmental adaptability: It can withstand high temperatures (>1000℃) and high humidity environments (RH>90%), and is suitable for multi-scenario applications in greenhouses and open-air farmlands.
Precautions for use and safety regulations
Avoid use on sensitive crops: Fruit trees that are sensitive to copper ions, such as peaches, plums, and apricots, should be prohibited from use, and pesticides should be avoided during the flowering and young fruit stages.
Concentration control: The recommended concentration range is 50-200 mg/L. Excessive use may cause leaf burns or soil copper accumulation.
Mixing taboos: Avoid mixing with foliar fertilizers or acidic pesticides containing metal ions (such as zinc and magnesium) to prevent precipitation or pesticide damage.
Future development direction
Intelligent controlled release technology: Develop coated copper oxide microparticles to achieve on-demand release of copper ions and extend the efficacy period.
Multifunctional compound preparations: Combine copper oxide with biostimulants to take into account both bactericidal and growth-promoting functions, such as enhancing crop photosynthetic efficiency and stress resistance.
Green and sustainable application: Promote nano copper oxide to replace traditional high-dose copper preparations, reduce ecotoxicity, and help achieve agricultural carbon neutrality goals.
Summary
Copper oxide has become an important tool for crop disease prevention and control due to its unique physical and chemical properties and multiple mechanisms of action. From traditional spraying to breakthroughs in nanotechnology, it has shown great potential in improving crop health and reducing dependence on chemical pesticides. Scientific application and technological innovation will promote the more efficient and safer development of copper oxide in the agricultural field.