NEM-EMERGE: An integrated set of novel approaches to counter the emergence and proliferation of invasive and virulent soil-borne nematodes

Lead Institute OL Institute of Organic Farming

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The EU joint project NEM-EMERGE is concerned with the spread of plant-damaging nematodes and its suppression in soils. Resistance in crops is endangered by further rising temperatures. In one of the work packages of the project, The Julius Kühn-Institute and the Thünen-Institute are working with field and vessel experiments to determine whether the soil microbiome can be influenced by biological processes in such a way that it is effective against the nematodes.

Background and Objective

Soil-borne plant-parasitic nematodes pose a biosecurity risk to global food production. They cause an estimated annual loss of 110 billion Euros worldwide. Root knot nematodes (RKN) and potato cyst nematodes (PCN) rank 1st and 2nd in the top 10 high-impact plant parasitic nematodes. They damage the plant roots, hinder the uptake of water and nutrients from the soil and make the plants more sensitive to increased temperatures and drought. Global warming has led to a migration of previously undiscovered "tropical" root knot nematode species northwards. In addition, heat waves endanger the effectiveness of resistance genes in crop species and new virulent nematode strains have emerged due to the long-term use of a small variety pool with resistance. Also the use of non-specific nematicides in conventional farming is prohibited today. Therefore, there is an urgent need to find integrative, sustainable solutions in both conventional and organic farming to counteract these problems.

The aim of the joint works of the Julius Kühn-Institute for Epidemiology and Pathogen Diagnostics, of the Julius Kühn-Institute for Crop and Soil Science and of the Thünen-Institute of Organic Farming is to investigate the effects of different precursor crops and of other biological methods on the microbial regulation of plant parasitic nematodes in the soil.

Approach

Field trials are carried out on organically farmed potato fields. Various preciding cover crops and some biologically active substances are tested. Persian clover (Trifolium resupinatum L.), Black Oats (Avena Strigosa) and Black Oats in a mixture with Crotalaria (Crotalaria juncea), a tropical legume known to suppress nematodes, serve as preceding crops. In addition, the addition of the fungus Pochonia chlamydosporia, which is active against nematodes, in the sowing of Crotalaria, an overseeding of the potato ridges with Crotalaria and the effect of the addition of green pellets of Nasturtium (Monks Cress, Tropaeolum majus L.) are investigated. The microbiome is extracted from the pre-treated soils and its effect on the development of selected plant parasitic nematodes is investigated in greenhouse experiments with potatoes.