Mycorrhizae against nematodes in citrus

Researchers have presented a promising solution for controlling citrus nematodes (Tylenchulus semipenetrans), responsible for global losses estimated at US$119,7 million annually. Their study explores the use of arbuscular mycorrhizal fungi (AMF) as an ecological alternative in the management of this devastating pest.

Citrus nematodes mainly affect tropical and subtropical regions, reducing production by up to 30%. They compromise the root system of plants, making it difficult to absorb nutrients and water.

Promising biological solutions

The study focused on two AMF species, Funneliformis mosseae e Rhizophagus irregularis, applied to two widely used citrus rootstocks: Citrus aurantium e Carrizo citrange. Fungi have shown efficacy in reducing nematode populations, achieving reduction rates of over 95% in soil and up to 88% in roots.

Furthermore, treated plants showed significantly greater growth compared to non-inoculated plants. For example:

• The dry biomass of plants treated with F. mosseae was up to 1,85 times greater.

• There was an increase of up to 65% in root length in rootstocks colonized by mycorrhizae.

How do fungi help?

Mycorrhizal fungi form symbiotic associations with plant roots, improving nutrient uptake and increasing resistance to biotic and abiotic stresses. They alter the composition of root exudates, making it difficult for nematodes to locate plants and strengthening natural defenses.

Furthermore, mycorrhizae stimulate the production of organic metabolites, such as citric and malic acids, which create an unfavorable environment for nematodes.

Next Steps

Although the results are promising, the researchers highlight the need for additional studies under field conditions to assess the large-scale impact and economic viability of mycorrhizae application in global citrus farming.

More information can be found at doi.org/10.1016/j.napere.2024.100104