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  • Crop soil
    • Essential laboratory tests
    • Soil texture and structure
    • Clay-humus complexes and cation exchange capacity
    • Other interesting data that can be included in a laboratory analysis - limitations of laboratory analyses
    • Soil acidity and alkalinity
    • Humus; formation and evolution
    • Soil fertility; is the apocalypse coming?
    • The microbial world and soil fertility
    • Rhizosphere, mycorrhizae and suppressive soils
    • Correction of a very clayey or too calcareous or too sandy soil
    • Estimation of humus loss
    • Compost production for a vegetable garden
    • The different phases of composting with a thermophilic phase
    • Weed management in the vegetable garden
    • Ploughing or no-ploughing?
    • The rotovator, the spade-fork and the grelinette
  • Fertilization
    • Synthetic or organic fertilizers?
    • The reasoning behind fertilisation in the vegetable garden
    • Examples of rational fertilisation for some vegetable plants
    • The problem of nitrogen assimilation in organic farming
    • Can vegetables be forced to grow?
    • Brief description of some mineral fertilizers
    • Tools for measuring nitrates
    • It is easy to cheat in organic farming
  • Biocontrol
    • Integrated Biological Crop Protection; first approach
    • Agroecology and ecosystem services in agriculture.
    • Vegetable garden and biodiversity areas
    • Permaculture; an example of pseudoscience in agriculture
    • Mandatory control of regulated pests
    • Anti-insect nets
    • Imports of beneficial auxiliaries
    • against aphids
    • Against whiteflies and scale insects
    • Against beetles, wireworms, cutworms, cortilian beetles, tipulas, ants
    • Against mites, trips, bedbugs
    • Crop rotation
    • Varietal choice
    • Solarisation and false sowing
    • Biocontrol plant protection products
    • Biostimulants
    • Other methods to reduce the risk of disease
  • Treatments
    • Organic or conventional treatments against pests
    • Some remarks on pesticides registered in organic farming
    • Copper and sulphur compounds
    • Pyrethrins
    • oil of neem and spinosade
    • The virtues of nettle manure under the magnifying glass
  • More

Introduction to integrated methods in the vegetable garden

Integrated Biological Protection (IBP)

Chapter : Biocontrols

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⇒ Integrated Biological Protection ; first approach.

- Agroecology and ecosystem services in the vegetable garden.

- Vegetable garden and biodiversity areas.

- Permaculture; an example of pseudo-science and mysticism in agriculture

- Mandatory control of regulated pests.

- Anti-insect nets.

- Imports of beneficial organisms.

- Against aphids

- Against whitefly and mealy bug

- Against beetles, wireworms, cutworms, cortilian beetles, tipulas, ants

- Against mites, trips, bugs

- Crop rotations

- Varietal choice

- Solarisation, false seeding and tillage in frosty periods.

- Biocontrol plant protection products.

- Other methods to reduce the risk of disease

- Biostimulants.

- Limitations of biocontrol methods.

First approach.

For more than 50 years, the development of the chemical industry has provided an effective response to crop-threatening pests becoming an essential modelhas and widespread model for plant protection. Fertilisers and pesticides have enabled high yields to be achieved to meet the growing world population (a). But pesticides have a negative effect on the environment and have eventually selected for bio-aggressor that are resistant to the molecules on the market. These pesticide resistances have also developed in the vegetable garden; for example, the green aphid Myzus persicae, some strains of which survive neonicotinoids and pyrethroids (and related molecules; the pyrethrins approved for organic farming) (1). This aphid, which likes peaches, is very polyphagous and is content with at least 50 botanical families, including cucurbits (cucumbers, gherkins, etc.), solanaceous plants (potatoes, etc.) and brassicas (turnips, etc.). Research was then directed towards less aggressive alternative solutions: selection of varieties more resistant to diseases, biological control by spraying predators of bio-aggressors, use of traps containing hormones, etc.

Nowadays, we no longer treat crops blindly with multipurpose combinations containing different plant protection products as soon as we discover a spot on a fruit or a leaf. A pest does not have to be dreadful, a disease can be benign and not require any treatment, and the removal of a diseased organ is sometimes enough to eradicate an emerging disease. Plant protection products have also been improved to reduce their dosage and to target pests more effectively, with less impact on the environment.

To reduce the use of pesticides, an overall strategy has been defined called
Biological Integrated Protection (BIP) or, for fruit, Integrated Fruit Protection (IFP). BIPs and IFPs include biocontrol techniques that consist in optimising the interactions between the different components of an ecosystem in order to reduce pest pressure (biodiversity corridors, importation of beneficial insects, physical protection against insects, sterile insect technique (SIT), biocontrol plant protection products....). However, it is also necessary to take into account the formidable capacity of pathogens and pests to adapt to their environment, which sometimes requires the use of pesticides approved for use in organic farming, or even a return to synthetic pesticides.

In integrated biological protection, pesticides are used when all other methods have failed, but not under any conditions. Pest populations must exceed a threshold beyond which irreversible crop damage occurs, resulting in unacceptable economic losses. Biocontrol plant protection products, including those approved for organic farming, are used first. If this fails, synthetic pesticides are then used.

Biocontrol techniques cannot solve all the problems encountered. In addition, the farmer often has to deal with problems of use that are less flexible than those of plant protection products, such as the constraints of conserving living organisms (bacteria, beneficial insects, etc.), negative interference with other biological phenomena, and the specificity and formulation of applications.


As for professional farmers, the gardener is confronted with the hazards of biological control. They sometimes have to deal with highly contagious diseases causing considerable losses (rust, mildew, etc.) which require anticipation of attacks. But, before taking their sprayers, many gardeners should first inform themselves about the characteristics of the bio-aggressors that would threaten their crop. Confusion with beneficial insects, unnecessary treatment of infections accompanying natural ageing, physical stress mistaken for microbial or fungal infection are some examples of common mistakes made in the vegetable garden.

Most of the biocontrol techniques that can be used in a vegetable garden are described by clicking on one of the menu items at the top right of this page.

a) From 1960 to 2005, the world population increased from 3 billion to 6.5 billion and the utilised agricultural area (UAA) per capita decreased from 4,300 m² to 2,200 m² (source UN-FAO).

When to act against bio-aggressor ?

Home gardeners find that they are often confronted every year with invasions of certain pests (e.g. aphids, larvae that burrow into carrots). Other bio-aggressor are occasional and are more or less aggressive depending on changing factors that the gardener cannot control (such as the climate). In the same region, a cultivated plot may be commonly invaded by one or more dominant bio-aggressor that do not exist (or are less numerous) in another plot located a few kilometres away.

The existence of dominant bio-aggressors that frequently return to crops requires anticipating their attacks by starting to modify the environment (for example, plantations that favour the attachment of pest predators, etc.), installing physical protection (anti-insect nets), and providing for the importation of useful auxiliaries. Occasional pests are treated on a case-by-case basis, depending on the degree of invasion and their aggressiveness, the resistance of the crops, which varies from one species to another, and above all the cultivation method (a poorly nourished and weak crop has difficulty resisting pest attacks).

Some examples of benign diseases that do not require phytosanitary treatment:

•

Apical necrosis on tomatoes (also called "apical rot" or "black ass")

This disease is characterised by black spots appearing on the fruit, but opposite the stalk. This benign disease is favoured by too much watering, or a boron deficiency revealed by laboratory analysis, or the choice of certain very sensitive varieties such as 'Roma'.

•

Growth cracks in tomatoes

caused by excess water.

•

Black root rot

blackening of the roots of carrots, endives, celery, melon, lettuce, tomatoes, beans, cucumbers: these are cryptogamic infections resulting from poor growing conditions that weaken the plants. To fight against these opportunistic infections, it is necessary to act on the cause and not on the consequence: excessive humidity, unbalanced or insufficient fertilisation...

•

Fumagin

black crust formed by several fungi accompanying insect bites, especially aphids, leafhoppers and mealy bugs. The fungi develop on the honeydew left by the biting insects without entering the plant. The plant is not invaded. It is sufficient to cut off the diseased parts, isolate the plants with physical protection and possibly treat the aphids if their predators are not yet present, or import aphid predators.

•

Opportunistic infections accompanying the natural ageing of a crop:

Some diseases considered problematic before harvesting, appear at the end of a crop cycle such as verticillium wilt and powdery mildew. It is then preferable to pull out the infested plants after harvest and before these diseases are transmitted to other more recent crops.

1) Résistance du puceron vert de pêcher (Myzus persicae) vis-à-vis des pyréthrinoïdes et des néonicotinoïdes -PLAN DE SURVEILLANCE 201 – ANSE – Ecophyto – août 2013

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