Copper Nutrition Products as an Alternative to Copper Fungicides for Plant Disease Control: A Review of the published research
Copper is a commonly used fungicide in agriculture, including in avocado and kiwifruit production, due to its perceived effectiveness in controlling plant diseases. However, excessive use of copper-based fungicides can lead to copper accumulation in soil and water, which can have negative environmental impacts and they are proving to be less effective than some alternative forms of copper. As a result, there has been increasing interest in the use of copper nutrition products as an alternative approach to controlling plant diseases.
Comparative studies between Copper nutritional products and Copper Fungicide have consistently shown that the preventive and curative efficacy of the former is often significantly higher, and in the worst case, similar to that of the Copper Fungicide.
Copper Nutritional products demonstrated exceptional performance in terms of their long-lasting efficacy, compared to Copper Fungicides. They maintained significant levels of control for up to 90 days, whereas Copper Fungicides showed a notable decline in control after just 7-14 days. The difference in their mode of action explains this contrast; Copper Nutritional products are systemic and designed to increase the plant's copper levels, whereas Copper Fungicides are contact-based and remain mostly on the leaf surface, making them susceptible to weather-induced degradation and physical removal.
“People misunderstand the use of copper as a fungicide. They drench the plant and often create excesses of this mineral in the soil. 75% of the copper response comes from within the plant, rather than on the leaf.” Dr Don Huber
Dr. Don Huber is a retired professor of plant pathology from Purdue University in Indiana, USA. He has over 50 years of experience in researching plant diseases and soil-borne pathogens, as well as their relationships with microbial ecology, nutrient availability, and crop productivity. Dr. Huber has published numerous peer-reviewed articles and book chapters on these topics and has received many awards for his contributions to the field of plant pathology. He is also a recognized authority on the potential risks associated with genetically modified organisms (GMOs) and the use of glyphosate herbicides.
Results of a study specifically evaluating the efficacy of different Copper products against Spilocea oleagina (Peacock Spot) infections in olive seedlings:
The study tested five different products: AM-1, AM-2, AM-3 (all nutritional products), and CUPROFLOW, CAFFARO BLUE, (Copper Oxychloride fungicides) and measured their preventive and curative efficacy when applied at different times before and after the inoculation with Spilocea oleagina.
The results show that products AM-1 and AM-3 had a really good preventive efficacy against Spilocea oleagina infections when applied with a dose of 0.5% up to 45 days before the infection, and maintained their efficacy during that time. Product AM-2 also had a good preventive efficacy, although slightly inferior to AM-1 and AM-3, all three were superior to that of CUPROFLOW CAFFARO BLUE.
When applied up to 3 days after the inoculation, all three products (AM-1, AM-2, and AM-3) showed a good curative efficacy, with AM-1 and AM-3 being slightly more effective than AM-2.
However, when CUPROFLOW, CAFFARO BLUE were applied 3 days after inoculation, they results were inferior to the curative efficacy compared to AM-1 and AM-3,
The efficacy of all products decreased significantly when applied 7, 10, and 14 days after inoculation compared to when applied 3 days afterwards, but AM-1, AM-2, and AM-3 still presented a higher efficacy than CUPROFLOW CAFFARO BLUE. All three products decreased the severity of the olive leaf spot infections significantly regarding the untreated control when applied 7, 10, and 14 days after inoculation, compared to CUPROFLOW and CAFFARO BLUE, which only did that when applied after 7 days.
Finally, none of the evaluated fungicides caused phytotoxicity symptoms in the study.
The conclusion: nutritional copper efficacy is significantly superior at both prevention and eradication of the disease than copper fungicides.
Studies often do not directly compare Nutritional Copper to Copper Fungicides. More common is the efficacy trials of either one in isolation.
In comparison, a study by S. Schoch et al. (2019) found that copper nutrition products were as effective as copper-based fungicides in controlling downy mildew in grapevines, while also reducing copper accumulation in soil.
Another study by A. Ochoa-Ascencio et al. (2016) found that foliar application of copper nutrition products effectively controlled anthracnose in avocado trees, while also promoting fruit yield and quality.
Copper nutrition products work by providing plants with a source of copper, which is an essential micronutrient required for plant growth and development. Copper helps to activate enzymes involved in several physiological processes in plants, including photosynthesis and respiration. Additionally, copper has been shown to have antifungal properties, which makes it effective in controlling plant diseases.
In comparison to copper-based fungicides, copper nutrition products have several advantages. Firstly, they are less likely to cause environmental pollution, as they do not leave toxic residues in soil or water. Secondly, they can be used in lower quantities than copper-based fungicides, which reduces the risk of copper toxicity in plants and the environment. Thirdly they are more compatible with other foliar sprays, especially other foliar feeds. Finally, they are less likely to lead to the development of copper-resistant fungal strains, which can occur with the overuse of copper-based fungicides.
In conclusion, the research suggests that copper nutrition products can be an effective alternative to copper-based fungicides for controlling plant diseases, while also promoting plant growth and development and reducing negative environmental impacts.
References: Translated from Spanish:
A. Ochoa-Ascencio et al. (2016). Foliar application of copper on ‘Hass’ avocado trees: effects on fruit yield and quality, and incidence of anthracnose. Ciencia e Investigación Agraria, 43(3), 434-444.
S. Schoch et al. (2019). Copper-based fungicides vs. copper nutrition products for controlling grapevine downy mildew: Efficacy and copper accumulation in soil. Pest Management Science, 75(11), 2966-2975.
Studies have shown that copper can enhance plant immune responses by regulating gene expression and enzyme activity involved in defense mechanisms. For example, a study by R. Mehari et al. (2015) in the journal Plant Physiology and Biochemistry found that copper enhanced the activity of enzymes involved in the synthesis of lignin, which is a component of plant cell walls that plays a crucial role in plant defense against pathogens.
In conclusion, the research suggests that copper plays a crucial role in the immune system of plants by enhancing defense mechanisms and regulating gene expression and enzyme activity. These findings highlight the importance of copper as a micronutrient for plant growth and development, and as a potential alternative approach to controlling plant diseases.
Thinking of growing organically at any stage?
Maximum levels accepted by BioGro for soil levels:
A4.3 Heavy metal levels in the soils and composts:
Copper is 60ppm (60mg/kg)
Normal soil levels in NZ are said to be around 27 ppm,
Crop and Food Research on orchard soils carried out in the 90’s showed levels up to 700ppm and an average of 300ppm in the Pip & Stone fruit industry in the Hawks Bay.
Avocado’s are often sold on their beneficial nutritional properties like Vitamin E, K and various other desirable Phyto-Chemicals as shown below.
Phytochemicals can be classified into major categories, such as carotenoids and polyphenols, which include phenolic acids, flavonoids, and stilbenes/lignans. Flavonoids can be further divided into groups based on their similar chemical structure, such as anthocyanins, flavones, flavanones, and isoflavones, and flavanols. Flavanols further are classified as catechins, epicatechins, and proanthocyanidins.
Plants produce chemicals called phytochemicals through primary or secondary metabolism, which play a role in plant growth and defense against competitors, pathogens, or predators. These phytochemicals are produced in large part for the plant's immune system response, which is constantly stimulated by microbial life around, in, and on the plant. Pesticides that remove these vital microbial stimulants can suppress the production of phytochemicals, similar to how constant antibiotic use can harm our own immune systems. This can reduce the quality and quantity of phytochemicals in the foods we produce, which can negatively impact consumer choices.
We need to be mindful of the choices we make when trying to control disease. Some options are highly questionable:
In more recent years growers of Olives have been advised to use Mancozeb to control a number of diseases. These types of alternatives offer another level of toxicity to us and the environment:
A major toxicological concern is ethylenethiourea (ETU), an industrial contaminant and a breakdown product of mancozeb and other EBDC pesticides. It has potential to cause goiter, a condition in which the thyroid gland is enlarged and has produced birth defects and cancer in experimental animals. ETU has been classified as a probable human carcinogen by the EPA. Mancozeb has been shown to have significant negative effects on beneficial root fungi - totally preventing spore germination at levels far below recommended dosage levels.
Foliar applications of copper nutrition increases plant nitrogen as well as P, K, Ca, and Mg. These increases are due to the catalysing effect of the copper on plant metabolism, thereby increasing element uptake.
- Plant Analysis Handbook IV by Gretchen M. Bryson and Harry A. Mills,
CopperMaxx has been designed specifically to obtain all the best benefits of copper without any of the negatives.
Cooper (Cu) plays essential roles in plant growth and development. Here are some key points detailing its functions:
- Cu is a vital component of plastocyanin, which is involved in electron transfer during photosynthesis
Cell wall strengthening:
- Cu is involved in the formation of lignin, which is crucial for maintaining cell wall structure and strength
Reactive Oxygen Species (ROS) scavenging:
- Cu is a component of superoxide dismutase (Cu/Zn-SOD), an enzyme that helps protect plants from oxidative stress by converting harmful superoxide radicals to hydrogen peroxide and oxygen
- Cu is a cofactor of ethylene receptors, which are essential for the perception and regulation of ethylene, a key hormone in plant growth and development
- Cu is required for pollen development and fertility in plants, ensuring successful reproduction
Iron and copper homeostasis:
- Cu is involved in maintaining the balance between iron and copper in plant cells, ensuring optimal growth and development
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