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Wally Richards
Wally Richardshttp://www.gardenews.co.nz
Wally Richards has been a gardening columnist for over 30 years. Check his websites - for gardening news and tips visit www.gardenews.co.nz. For mail order products visit www.0800466464.co.nz. Wally also has a gardening problem help line on 0800 466 464.

Gardening with Wally Richards: A new plant disease control

Curly Leaf disease news

Plant diseases appear when a plant is lacking in one or more elements or the plant is in stress for whatever reason.

Normally we spray a fungicide to prevent or control a plant disease which sits on the surface of the leaves and branches.

Dependent on the disease we use a copper fungicide or a sulphur fungicide alternatively the compound potassium permanganate and in some cases a combination of two or the whole three sprayed together.

In some diseases such as curly leaf on stone fruit trees (nectarine and peach) we apply a fungicide copper every 7 to 10 days; or again after rain, if we have not used Raingard in the spray.

With curly leaf in stone fruit, the disease often strikes when it rains because the spores are splashed up from the soil below but if the rain has washed off the copper fungicide then there is no protection.

Curly leaf in stone fruit is a difficult disease to prevent and dependent on how bad the leaves are damaged means a loss of some or even all the crop.

In severe cases the tree may die also.

Now this is interesting and extracted from an article I received recently…

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.

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.

Copper nutrition products work by providing plants with a source of copper, which is an essential micro nutrient 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 anti-fungal properties, which makes it effective in controlling plant diseases.

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.

I am pleased to say that we now have a copper nutrient which I have called Wallys Super Copper Nutrient and is available from our mail order web site in 250 ml bottles.

Or you can ask your local garden centre to order the product in for you.

I was told of a trial that was done on a stone fruit tree to prevent curly leaf.

Only one part of the tree was treated and that part had no curly leaf and even the following season still no curly leaf where the rest of the tree suffered from the disease.

Used at the rate of 10 mils per litre for initial application and then at 5mils per litre of water for maintenance.

If you have a stone fruit tree that suffers from curly leaf then spray the tree now before spring movement at 10mils over the branches where the leaf buds are.

Coverage should be as good as able all over the tree.

When there is a show of leaves later on spray again at the 5 mil rate.

If the tree is flowering only spray the foliage at the end of the day when pollination has finished for the day.

Another spray of foliage at 5 mils per litre of water can be done after fruit has set.

Trials that I have read about diseases on other plants have also being very good at controlling various disease problems.

Thus where you have problem diseases such as on roses and other plants this copper nutrient maybe the answer you them also.

Dr. Huber also commented that the only reason copper fungicides helped in control of various diseases is that some of the copper would get into the plant which would then help the plant as written above.

But applying Wallys Super Copper Nutrient cuts to the chase reducing or eliminating the need for copper fungicide sprays.

Image credit: Markus Spiske

Order from www.0800466464.co.nz.

Products mentioned are from Wallys Range of products and can be found in some garden shops or by Mail Order on www.0800466464.co.nz

Problems ring me at: Phone 0800 466464
Garden Pages and News at www.gardenews.co.nz
Shar Pei pages at www.sharpei.co.nz
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