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Role Of Nutrients In Plant Disease & Pest Management

Plant disease & pest management using chemical pesticides raises serious concerns about food safety, environmental quality and pesticide resistance. These concerns have dictated the need for alternative plant disease & pest Management techniques. In particular, plant nutrients could affect the disease tolerance or resistance of plants to pests and diseases.

This is evident in the increasing pressure on growers to grow healthy flowers, fruit and vegetables with less and less chemical pesticides. The export markets normally check for pesticide residues in the produce and high MRL levels can limit market access. With the new Horticultural Standards in Kenya being gazetted – there is also more pressure from the local markets on pesticide use and residues..

Mineral Nutrition & Plant Disease

Before the First World War, pest and disease control was achieved through a combination of proper crop husbandry, crop rotation and sulphur and copper. During the First World War, a great deal of research was done on chemicals for chemical warfare. An off shoot of this research was production of chemicals that were effective for pest and disease control in crops.

There was a major agricultural revolution. Pest & diseases were controlled,  and food production became more secure and yields increased. It was only years later that we became aware of the side effects of these chemicals on human health. Not all chemicals are bad, and without proper pest and disease control we would be unable to feed the world. However, it’s important to grow responsibly and minimize pesticide use where we can.

Before the First World War a great deal of research was done on the role of plant nutrients in plant disease and pest management, and this work is now being re-visited and expanded on.

Plant Disease & Pest Management In Sustainable Agriculture

Soil Structure & Drainage

Many diseases start due to problems with rooting, soil structure, no oxygen, lack of drainage and water logging. A deep, well drained soil with a good crumb formation is your first line of defense against plant diseases. Next the moisture levels and temperatures play an important role in ‘activating’ pathogens. Generally higher moisture levels and temperatures encourage diseases and reduce the egg to egg time of insects’ life cycles. Sadly, in East Africa we do not have the luxury of cold winters – that can kill off many diseases and insects.

Soil pH

Next, the soil pH has a great deal to do with how fast a disease progresses.  Acidic soils tend to suppress quite a few diseases – however they also suppress nutrient availability and crop yield – so approach with care. The soil, water and drip pH determine the availability of nutrients to plants and can create excesses and deficiencies that can encourage insect and disease growth. It is better to keep the pH at the optimum for the plants requirement to grow a healthy disease resistant crop.

Plant Nutrition

Proper plant nutrition is your next line of defense. Any nutrient that is deficient or in excess will increase a plants susceptibility to diseases and pests. Nutrients that are known to influence pests and diseases in plants are: – the Nitrogen form, Potassium, Calcium, Sulphur, Chlorine, Nickel, Manganese and Silicon.

Calcium is a primary disease controlling nutrient.  The amount of calcium in the soil determines many things!  1) The pH, 2) The structure 3) The aeration. Check Calcium levels and ensure you have at least enough and at best luxury levels.

Calcium in the plant is used to make Calcium Pectate – this determines how strong the cell walls are, and how resistant they are to insect and disease attack. Many diseases in many crops can be prevented by having enough Calcium in the plant tissue. Low calcium in the soil results in compacted waterlogged soil, with poor nutrient uptake efficiency and weak stressed plants.

Calcium is known to suppress club root in cabbagefusarium wilt in tomatoes, erwinia soft rot in potatoes and botrytis blight in many fruits and vegetables. Adequate Calcium is essential for good shelf life of produce.  Calcium is taken up via the transpiration stream and can become definition in cool, overcast or humid weather conditions.

plant nutrition its role in insect pest and plant disease control
The Plant-Disease Triangle. For a disease to happen, it needs a pathogen, a susceptible host and a favourable environment. Disrupting any of these will reduce the problem.

Potassium plays a major role in insect and disease suppression. Potassium deficient plants are very susceptible to both diseases and the weather!  In many areas we are lucky to have enough or excess potassium in the soils.  However, it can become easily fixed into certain soil types, e.g. illites and clays.  Unlike most plant nutrients – potassium does not become a part of any plant constituent and remains present in the plant sap. It is very mobile in plants and quickly moves from the older to younger leaves and to identify a deficiency you need to do a leaf analysis on both and compare.

Excess potassium can also suppress or encourage diseases depending on the total nutrient status of the plant. In general potassium will suppress most diseases but can encourage Erwinia rots, downy mildew and nematodes.  The Nitrogen: Potassium (N:K) ratio is also critical for some diseases and insects. A high N:K ratio can encourage diseases. A high K:N ratio tends to reduce disease severity and in conjunction with adequate phosphorous can reduce reproduction in aphids.

role of nutrients in controlling plant diseases

Nitrogen excesses tends to produce weak, fast growing plants that are very susceptible to insects and disease damage.  Most damping off disease occur due to excess nitrogen, high nitrogen encourages botrytis in plants that would normally be resistant to it. The form the nitrogen is supplied to plants in can also have a major effect on disease resistance. Nitrogen can be absorbed by plants as the reduced NH4 form or the oxidized NO3 form.  NH4 reduces pH while NO3 increases pH.  Diseases react differently to the N-form. Nitrate suppresses Fusarium wilts and Rhizoctonia root rots while ammonium suppresses most other soil borne diseases.

preventing plant problems through proper fertilizer and nutrient uptake

Chlorine is not generally considered a plant nutrient and can be toxic to many plants. However, research has found that in chloride resistant plants, chlorine can suppress plant diseases e.g. fusarium crown rot in asparagus, Rhizoctonia crown rot in beets, Fusarium Yellows in celery, and smut and stalk rot in corn. In most cases an increase in chloride resulted in an increase in manganese in the leaf tissue.

Managanese. Plant testing and research has shown a good correlation between the concentration of Manganese in healthy plant tissue vs diseased plant tissue. Fungal and to a large extent, bacterial diseases are reduced in the presence of adequate manganese uptake, while viral diseases may be enhanced by enhanced plant uptake.

Manganese tends to be abundant in the soil, the limiting factor being the efficiency of uptake. Practices that improve manganese uptake tend to reduce diseases. Mulching, optimum pH, organic matter, soil temperatures and microbial activity in the soil. Glyphosate can reduce manganese uptake and encourage take all. Potato scab is mitigated by lowering soil pH, irrigating or foliar feeding manganese.  Some fungicides e.g. Mancozeb are much more effective in the manganese form.

Nickel is required in very small amounts and is generally sufficient in most horticultural soils.  It is considered an ultra-micronutrient and not much attention has been paid to it.  It is thought that nickel is important for nitrogen cycling in plant tissue and for eliciting the plants immune response by helping with phytoalexin production.  Nickel salts are effective fungicide sprays against rust.  Nickel uptake can be reduced in cold dry soils and in the presence of excess zinc, copper, manganese, iron, cobalt, magnesium and calcium.  More work needs to be done on nickel.

Sulphur is very important in disease control – it is required to induce the plants natural resistance to fungi through triggering natural metabolic processes.  This is now termed SIR – sulphur induced resistance.  Sulphur also has a topical toxic effect on funguses and mites – hence the use of sulphur burners in some greenhouses.

Silicon is the second most abundant mineral in soil.  Adequate levels of silicon in the plants impart a healthy resistance to most diseases, and the source and rate of applied silicon can strongly affect the control of many fungal diseases in many plant species.  Effective / affordable / and practical solutions are required for application of silicon to crops that can accumulate it, as it has been recognized that the use of silicon in pest and disease control would be a viable method of reducing fungicide use in many areas of agriculture.  More research must be done on this.

Silicon in various forms has proved to be an effective method of insect control.  High levels of accumulated silicon in stalks and leaves can discourage chewing insects, silicon can dissolve chitin, causing dehydration in insects, and silicon can block insects spiracles – preventing oxygen from getting into their bodies.

High levels of EC (salinity) or Sodium (sodicity) can greatly affect plant nutrient uptake and healthy plant growth and encourage diseases, nematodes and insects.

As you can see – the plant nutrition plays a huge role in determining plants’ tolerance to insect and diseases, and much can be done with optimizing plant nutrition to reduce pesticide use. For more information on this, and to test the nutrient status of your plants please contact us on

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“The future of indoor and greenhouse vertical farming depends on physics for high quality production”

Affinor Growers has signed a commercialization agreement with Britespan Building Systems to engineer and manufacture new polycarbonate greenhouses co-designed by Affinor and Britespan.

Britespan currently designs, engineers, and manufactures prefabricated buildings in Canada and internationally. Affinor conceived the “Atlantis” greenhouse by adding a polycarbonate material to the outside surface of the Britespan building trusses, dramatically improving certain key performance characteristics of commercial greenhouse systems. The Atlantis Greenhouse optimally accommodates Affinor’s vertical growing technology and processes.

Affinor will be the exclusive worldwide dealer of the Atlantis Greenhouse and Britespan will be the exclusive worldwide supplier of the Atlantis Greenhouse Structure for a term of ten years, with automatic 2-year renewals thereafter.

Affinor and Britespan have also agreed to work together to manufacture the first full-scale demonstration greenhouse to be built adjacent to Affinor’s current lease location on Page Road in Abbotsford.

CEO Nick Brusatore commented: “The future of indoor and greenhouse vertical farming depends largely on physics for high quality production. The Atlantis Greenhouse design accommodates the environmental requirements for automated, vertical farming production, to prepare us for radical climate changes and the various environments we face globally. I expect that the Atlantis Greenhouse will be very competitive and environmentally superior.”

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More than 1.1 million tons of greenhouse vegetables have been harvested in Russia since the beginning of the year

The collection of vegetables and green crops in winter greenhouses in Russia amounted to 1.134 million tons since the beginning of the year, the press service of the Ministry of Agriculture of the Russian Federation reported on November 5.

In the harvested crop, the share of greenhouse cucumbers is 651 thousand tons, and of tomatoes – 458.6 thousand tons. For the same period in 2020, the collection of vegetables in greenhouses amounted to 1.094 million tons, which is 3.6% less than this year.
The most developed production of greenhouse products in Lipetsk, Moscow, Volgograd, Kaluga, Novosibirsk regions, Krasnodar and Stavropol Territories, in the republics of Karachay-Cherkessia, Tatarstan and Bashkiria, they are among the top ten regions-leaders in the industry.
The development of the sub-industry is facilitated by measures of state support, first of all, preferential lending. For farmers who grow vegetables in greenhouses using supplementary lighting technology, there is also an opportunity to receive subsidies within the framework of the state program for the development of agriculture.
For the regions of the Far East, from 2022, compensation is provided for 20% of capital costs for the construction and modernization of greenhouse complexes.
The Ministry of Agriculture expects to maintain positive dynamics at the end of 2021. The forecast for the harvest of greenhouse vegetables is more than 1.4 million tons.
Recall that the cultivation of vegetables in winter greenhouses received a significant impetus for development within the framework of the import substitution program after the introduction of sanctions by Western countries against Russia in 2014 due to the annexation of Crimea.

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In 2023, the second stage of the complex of berry greenhouses will start operating in the Moscow region (RF)

The construction of the second stage of a complex of tunnel greenhouses for the production of berries with an area of ​​90 hectares in the Naro-Fominsk urban district of the Moscow region (RF) will be completed in 2023.


This was announced by the Minister of Agriculture and Food of the Moscow Region: “In the Naro-Fominsk urban district of the region, film tunnels with a drip irrigation system have been installed for growing fresh berries in greenhouses. On the site of the first stage with an area of ​​50 hectares this year the first harvest of berries – strawberries, blackberries and raspberries – was harvested. Work is underway on the construction of the second stage of tunnel greenhouses with an area of ​​90 hectares, which is planned to be completed in 2023 ”.

See also: New Year’s Eve without the smell of tangerines – Russia bans the import of tangerines from Turkey during the high season!

At the moment, the site has been fully prepared, it is equipped with roads, communications, a warehouse for storage and utility rooms.


Greenfields Agro LLC is implementing an investment project for the placement of tunnel greenhouses for growing berries on 148 hectares of land. The project is planned to be implemented in 3 stages. All crops are planned to be grown in tunnels using a substrate, writes the Ministry of Agriculture of the Russian Federation.

When growing berries, a bio-plant protection system is used, the berries grown in these greenhouses comply with the organic production standard. Completion of all stages of the investment project will allow Greenfields Agro to increase the gross production of berries to 2 thousand tons.

According to the minister, the total investment will amount to 1 billion rubles. The project will create more than 175 permanent and 600 seasonal jobs.


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