Yannie Trottin, ACTA

Root-knot nematodes (Meloidogyne spp.) are major and increasing soilborne pests on different protected vegetable crops in a crop system: for example, tomato, aubergine, cucumber, melon or courgette in spring / summer and lettuce in winter… Nematodes can be maintained in the soil even if there is a crop rotation with different sensitive crops to the pest.

Less and less chemical products can be used against this pest, so it is important to find alternative methods such as solarisation, resistant variety or biocontrol products.

Some of these products are already registered but they are still insufficiently known.

The objective of the team led by Ms. Yannie Trottin of the EUCLID partner ACTA/Ctifl is to study the efficacy of biocontrol agents on lettuce. A trial was carried out in an insect-proof glasshouse on lettuce pots with a homogeneous mixture of naturally-infested soil by Meloidogyne hapla and sand. This method showed a great interest in another kind of trial because of the heterogeneous distribution of nematodes in the soil (Fig.1).

 

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Fig. 1. Lettuce crop in pots in one experimental compartment. Fig. 2. Observations on lettuce roots and counting of galls.                                           

 

The trial was set up in the Spring 2016 with three replications (or compartments) and four treatments:

- Control (water) - Flocter (Bacillus subtilis), 80kg/ha, 1 application 2 days before planting

- BioAct®(Paecylomyces lilacinus), 0.8L/ha, 20mL/m3, 0.8L/ha (3 applications: 15 days and 2 days before planting, then 15 days after planting)

- Nemaquill (a fertilizer in Spain, Racinett in France with a BCA), 40L/ha, + acidifying agent, 1 application before planting.

 

The observations were done after one cycle of nematodes i.e. 46 days after planting, about 380°Cdays (Fig.2). Per root system, galls on roots were counted on 10 plants per treatment and per replication.

The root system was weighed on each observed plant. In the experimental controlled conditions, no significant difference was found between the treatments (number of galls and weight of roots).

There was a great interest of the controlled conditions in pots for the trial with an homogeneous naturally-infested soil by nematodes but some difficulties emerged for the treatments (applied dose has to be better defined), management of irrigation in the pots…

The results confirm that the efficiency of these products is highly related to conditions of treatments and characteristics of the soil.

Another trial is planned in Spring 2017 (a water control and 3 products – Flocter, Nemaquill and NemGuard (garlic extract) that has just been registered in France on vegetables such as lettuce, tomato…). Experimental conditions have been discussed and trials will be carried out in naturally-infested soil in small plots but with a great number of replications.