1. Presentation

Characterization of the technique

Description of the technique:

Information originally from the Guide for the design of fruit production systems that are economical in phytosanitary products (2014) / Technical sheet no. 2. For more information: see link

The Principle

Preserving beneficial insects in the orchard is one of the key points of biological control by conservation. This strategy consists of avoiding or limiting agricultural practices that are unfavorable to the development of beneficial insects, either directly (e.g. mortality due to application of non-selective pesticide) or indirectly by suppressing their resources (e.g. mowing the grass cover).

Indeed, a reasoned management of agricultural practices is necessary to avoid directly or indirectly eliminating beneficial insects. Therefore, it is important not to remove or significantly alter the quality of habitats and resources, and to use (as a last resort) pesticides with low impact on beneficial insect populations.

Example of implementation:

Levers to preserve beneficial insects:

1) Extensive grass cover management within the orchard

On the inter-row

> Reducing the number of cuts of the grass cover favors the presence of prey (e.g. aphids of grasses, dipteras, collembolas…) and thus that of predators (e.g. earwigs in pome fruits, among other predators of woolly aphids and psyllids, arachnids, rove beetles…).

> Cutting higher (10 cm or more) or not mowing the entire plot at once by mowing, for example, every other row partially preserves resources for beneficial insects; the complementary rows will be mowed when flowers reappear on the first rows.

> Late mowing is recommended whenever possible. Furthermore, mowing dates should be reasoned to avoid secondary pest problems (a bio-aggressor that is only problematic in the absence of the primary bio-aggressor or protection directed against the primary bio-aggressor). For example, avoid mowing just before harvest so that thrips or grasshoppers do not migrate from the herbaceous layer into the trees for stone fruits.

> Shredding the grass (by rotary mowing) destroys many beneficial insects, so it is preferable to opt for mowing or rolling the grass.

> The application of nitrogen fertilization is discouraged on grass covers to limit growth and promote botanical biodiversity in orchards.

> A management method of the inter-row that preserves resources for beneficial insects consists of sowing grass species resistant to tool passage under wheel tracks and species favorable to beneficial insects.

On wheel tracks and borders

"Extensifying" their maintenance as much as possible is achievable through the following practices:

> Do not fertilize them,

> Perform only late mowing,

> Alternate mowed areas every two or three years,

> Remove cut material to promote a diverse and attractive flora for beneficial insects or graze them with low livestock density.

On the row

There are strategies to maintain the row and thus preserve beneficial insects in the orchard:

> Limiting soil work or performing it under good conditions (dry weather…) helps to not or minimally disturb soil fauna (e.g. ground beetles).

> The addition of organic amendments promotes decomposer arthropods, for example collembolans, which are a food source for many predators.

NB: Elements related to alternative techniques to herbicides for row maintenance are developed in the technical sheets: “Using mulches or mulching on orchard rows”, “Practicing mechanical weeding in orchards” and “Using the sandwich method to manage weeds in orchards”.

2) Adapted chemical control for the preservation of beneficial insects

It is essential to adapt chemical control to avoid killing beneficial insects (directly). Adapted control consists of choosing pesticides that are least toxic to beneficial insects and using them under appropriate conditions (absence of flowers, low wind…). The control strategy must of course prioritize alternative methods (e.g.: mating disruption or netting to reduce the number of insecticides) and use phytosanitary products as a last resort.

For example, the absence of broad-spectrum insecticides is sufficient to allow phytoseiids and psyllid predators to regulate, respectively, populations of phytophagous mites and pear psyllids.

Implementation period

Spatial scale of implementation Plot

Farm

Application of the technique to...

All crops: Easily generalizable

Easily generalizable

Preserving beneficial insects through reasoned grass cover management is an issue that concerns and can be considered for all fruit species.

Regulation

2. Services provided by the technique

3. Effects on the sustainability of the cropping system

"Environmental" criteria

Effect on air quality: Increasing

Phytosanitary emissions: DECREASE

Effect on water quality: Increasing

Pesticides: DECREASE

Other: No effect (neutral)

"Agronomic" criteria

Functional biodiversity: Increasing

Increasing

A reasoned management of agricultural practices in the orchard promotes the preservation of beneficial insects through the presence of food resources and refuge.

"Economic" criteria

"Social" criteria

4. Organisms favored or disadvantaged

Favored Pests

Organism	Impact of the technique	Type	Details

Disadvantaged pests

Organism	Impact of the technique	Type	Details

Favored beneficial insects

Organism	Type	Details
Spiders	Natural enemies of pests
Ground beetles (predatory and granivorous)	Natural enemies of pests
Earwigs (predator)	Natural enemies of pests	Reducing the number of cuts of the grass cover favors the presence of prey (aphids of grasses, diptera, collembola) and thus that of predators such as earwigs in pome fruits.

Disadvantaged beneficial insects

Organism	Impact of the technique	Type	Details

Favored climatic and physiological accidents

Organism	Impact of the technique	Details

Disadvantaged climatic and physiological accidents

Organism	Impact of the technique	Details

5. For more information

Beneficial insects in orchards and vineyards
-Baudry O.

Ctifl editions, Book, 2001

2nd edition. Ctifl editions, Paris, 109 p.

Non-cultivated spaces and biodiversity in orchards. Towards better consideration
-Tronel C., Ricard J.-M.

CTIFL, Technical brochure, 2012

Infos-Ctifl, 286, 24-27.

Integrated fruit production guide
-Station la Pugère – CRA PACA

Technical brochure, 2014

Objectifs Info Arbo, 5-7.

Focus on: spiders in orchards
-Ricard J.-M., Mandrin J.-F.

CTIFL, Technical brochure, 2013

To access the brochure: http://www.ctifl.fr/ecophytopic/point_sur/PSAraigneesVerger.pdf

Focus on: Ground beetles in fruit and vegetable crops
-Garcin A., Picault S., Ricard J.-M.

CTIFL, Technical brochure, 2011

Le Point sur, no. 31. Ctifl, Paris, 8 p.

To access the brochure: see link

Biological control by conservation of biodiversity – Functionality of soil arthropods in pest control of the apple tree (2nd part).
-Ricard J.-M., Boreau de Roincé C., Garcin A., Jay M., Mandrin J.-F., Lavigne C., Bouvier J.-C. Mille M.

CTIFL, Technical brochure, 2010

Infos-Ctifl, 273, 24-29.

Biological control by conservation of biodiversity – Functionality of vertebrate and invertebrate beneficial insects in pest control of the apple tree (1st part).
-Boreau de Roincé C., Ricard J.-M., Garcin A., Jay M., Mandrin J.-F., Lavigne C., Bouvier J.-C.

CTIFL, Technical brochure, 2010

Infos-Ctifl, 263, 10-15.

Manipulation of habitats in organic orchards and their environment for pest control. Elements for modulating tree-pest-beneficial insect relationships
-Simon S., Sauphanor B., Defrance H., Lauri P.E.

Peer-reviewed journal article, 2009

Innovations Agronomiques 4, 125-134.

On the control of apple aphids: the role of spiders in the canopy
-Ricard J.-M., Boreau de Roincé C., Mandrin J.-F., Garcin A., Jay M., Lavigne C., Bouvier J.-C.