Metarhizium brunneum
Metarhizium brunneum is an entomopathogenic fungus used in biological control to target various soil-dwelling pests in agricultural and horticultural systems.
Description
Metarhizium brunneum is an entomopathogenic fungus used in biological control to target various soil-dwelling pests in agricultural and horticultural systems. This fungus parasitizes harmful insects in the soil as well as aerial pests, such as certain beetles, fly larvae, and aphids, which can damage plant roots and lead to significant crop losses. Its use offers a sustainable and environmentally friendly alternative to chemical pesticides.
When applied to the soil, M. brunneum infects target insects by penetrating their cuticle, where it grows and produces toxins that ultimately kill the host in 3 to 7 days. In France, it is used across a variety of settings, including vegetable crops, orchards, and ornamental plants, with careful management of timing and application conditions to maximize its effectiveness.
The appeal of Metarhizium brunneum lies in its favorable ecological profile, targeting specific pests without harming beneficial non-target organisms.
Mode of action
thumb|Mod of action of entomopathogenic fungi https://doi.org/10.1016/j.jip.2015.11.011 Metarhizium brunneum infects insect pests by attaching its spores to their cuticle (the outer shell of insects). The spores penetrate through the cuticle into the insect’s body in 3 to 4 hours, where they germinate and proliferate. The fungus releases toxins that paralyze and eventually kill the insect in 3 to 7 days by destroying its internal tissues. The dead insect becomes a source of spores, which can spread and infect other pests in the surrounding area.
Use of Metarhizium bruneunm as an insecticide
In France Metarhizium brunneum is available in the commerce in 2 different formulations, making it versatile for different types of application, each formulation adapted to different pests:
LALGUARD M52 GR by Lallemand Plant Care (formerly Met52 GR by NOVOZIMES): Rice grain inoculated with Metarhizium brunneum MA 43. Long term insecticide (1 year of efficacy) used against insect soil pests.
- Ornamental crops, strawberry, raspberry (soil treatment): Soil pests, 2 applications per year.
- Strawberry, blueberry, blackcurrant, gooseberry (soil treatment): Soil pests, 3 applications per year.
LALGUARD M52 OD by Lallemand Plant Care (formerly Met5 2OD by NOVOZIMES): Oil dispersion formulation for foliar pulverization containing Metarhizium brunneum strain Ma 43 (also known as Metarhizium anisopliae strain F52) 2.10¹² CFU*/L *CFU = Colony-Forming Units.
Greenhouses(max application per year: 10):
- Trees and shrubs: Whiteflies (Aleurodes). 10
- Edible-skinned and non-edible-skinned cucurbits: Mites, whiteflies (Aleurodes), thrips. 10
- Floral crops and green plants: Whiteflies (Aleurodes, proven efficacy on Gerbera). 10
- Strawberry: Mites, thrips. 10
- Pepper: Mites, whiteflies (Aleurodes), thrips. 10
- Tomato and eggplant: Mites, whiteflies (Aleurodes), thrips. 10
Open field (max application per year: 6):
- Onion, leek, vine, tomato, eggplant: Thrips.
- Leek: Thrips.
- Vine: Thrips.
Modalities of application
- Granular Formulation: 500–1,500 g/m³ of soil or 1,500 g/m³ of soil before or during planting.
- Liquid Formulation: Applied through foliar spraying for aerial pests 0,5 to 5 L/1 000 L or as a soil drench for subterranean insects.
- Both LALGUARD M52 G and LALGUARD M52 OD should be used as preventive treatment, as the efficiency of the product depends on the establishment of the fungi in the soil. Due to their mode of action based on biological infection, the effectiveness of the pesticides are limited as curative treatment.
- Use of Metarhizium brunneum is adapted to integrated pest management (IPM) which means that it can be used in combination with other pest management tools and strategies, as it has no known effect on non-target insects or other beneficial organisms.
For more indication on the use of these products please refer to Ephy (1)(2).
Price:
- 90€ for 1 liter for Lalguard OD. For a maximum application of 1.25L/hectare, it costs about 112€/hectare per application.
- 40€ for 1 Kg for Lalguard GR. For a maximum use of 0.5 Kg/m³, it costs around 20€/m³.
Conditions for optimal application
- Temperature: Ideal temperatures for Metarhizium brunneum efficacy range between 20°C and 30°C. It is best applied when soil conditions are conducive to fungal growth.
- Humidity: High moisture levels improve the effectiveness of the fungus, making it more likely to infect and kill target pests.
- Application Timing: Apply before or early in the pest life cycle.
- UV Sensitivity: The spores of Metarhizium brunneum are sensitive to ultraviolet (UV) light. It is recommended to apply the fungus in early morning or late afternoon to reduce exposure to direct sunlight.
- Homogeneity of the mix: For M52 GR application the grains need to be be mixed well enough for an efficient spore repartition
- Storage: Store in cool, dry conditions to maintain spore viability. Spores can lose effectiveness if exposed to high temperatures or moisture before application.
Advantages
- Environmentally Friendly: Metarhizium brunneum is a natural biocontrol agent that poses no risk to humans, animals, or beneficial insects like pollinators.
- Reduces Chemical Pesticide Use: By incorporating Metarhizium brunneum into pest management strategies, farmers can reduce the need for synthetic insecticides, promoting a more sustainable agricultural system.
- No Resistance Development: Unlike chemical insecticides, there is less likelihood for insects to develop resistance to this fungus because of the multiple targeted receptors involved in its infection process.
- Works on adult insects as well as larvaes
Precautions
Use well-maintained equipment and PPE (nitrile gloves, protective suits, masks) as specified for mixing, application, and cleaning.
Re-entry period: 6 hours in fields, 8 hours in enclosed areas.
Avoid use by immunocompromised individuals and do not mix with fungicides. Respect a 5m buffer zone near water and avoid harming beneficial fauna. Store below 4°C.
For more detailed information on handling the product based on Metarhizium brunneum, please refer to Ephy.
Metarhizium brunneum as a biostimulant
In terms of its use as a biostimulant, although research has shown its beneficial effects on plant growth and resistance to abiotic stresses, its use in this area remains experimental or in the development phase. The properties of Metarhizium brunneum that promote plant growth or enhance stress resistance are still under investigation for future applications, but its commercialization as a biostimulant is right now only for its use as a biopesticide.
That said, some companies and researchers are still exploring its potential in this field, and new products based on this fungus could emerge as research progresses.
Regulation
The list of biocontrol plant protection products in France is managed by the Ministry of Agriculture and Food. Current regulation: DGAL/SAS/2022-57 of January 19, 2022.
The list of authorized products for use in French territory is maintained by ANSES (French Agency for Food, Environmental and Occupational Health & Safety).
The products are authorized for use in organic farming.
Annexes
