Institut für Epidemiologie und Pathogendiagnostik
Nematode infestation in medicinal plants in Germany has so far only been investigated for a few plant species such as peppermint and parsley (Noskov et al. 2024a, b). Due to their low cultivation frequency, the host properties of medicinal plants for plant-parasitic nematodes (PPN) with high damage potential (Meloidogyne, Pratylenchus) are largely unknown. In organically managed, multi-location field trials, annual and perennial medicinal plants and wheat were examined for nematode infestation on roots and in the soil after strong evidence for plant damage by nematodes. Caraway roots (Carum carvi L.) showed a very high infestation with Pratylenchus spp. as well as showed typical symptoms of the root gall nematode Meloidogyne. For this reason, a more comprehensive study of the population dynamics of PPN will be carried out at two locations (Darmstadt, Kassel). In addition, the host properties of different caraway varieties against Pratylenchus neglectus and Meloidogyne hapla will be tested under greenhouse conditions. The aim is to determine the PPN propagation potential and to identify harmful PPN species. To determine the initial PPN population, soils under perennial caraway (Arterner variety), perennial wheat (Triticum aestivum x Thinopyrum intermedium) (origin Naturland propagation, mixture of five initial lines), perennial fennel (Berfena variety) and the fallow after Phacelia catch crop before spring wheat are sampled. At the site Domäne Frankenhausen near Kassel (DFH), Haplic Cambisol on loess, one mixed soil sample per plot (four replicates each) will be taken from 30 sub-samples (0-20 cm) in November 2024 and March 2025. At the Darmstadt site (FOR) (Haplic Cambisol) only in April 2025. A further sampling is planned for fall 2025 after the harvest of all crops. The nematodes are extracted from 250 ml of soil (4 variants x 4 turns) using an Oostenbrink elutriator and subsequent 48 h incubation in Oostenbrink trays (Hallmann & Subbotin, 2018). After concentration of the extracts to 10 ml, the PPN in 1 ml extract are quantified at genus level under 100x magnification and extrapolated to 100 ml soil. For resistance screening, seven varieties of caraway (perennials: Konczewicki, Rekord, Niederdeutscher, ASS, Prochan; annuals: Sprinter, Aprim) were not inoculated (control), inoculated with juvenile M. hapla, and inoculated with mixed stages of P. neglectus (x 10 replicates = 210 pots). Nematodes were inoculated with 1000 animals per pot (500 ml). After 56 days, above-ground biomass and roots will be harvested. P. neglectus is extracted from the roots cut into 1 cm long pieces using a spray booth (Mistifyer technique, Hallmann & Subbotin, 2018). M. hapla is extracted at the egg stage by treating the roots with 1% NaOCl (3 min on horizontal shaker at 400 rpm in PET bottles). The reproduction factor (RF = final population/inoculum value) is then determined. The investigations are part of a doctoral thesis (University of Kassel).Noskov I, Blum H, Komnik H, Hallmann J (2024) Host Status and Response Differences of Flat-Leaf and Curly-Leaf Parsley to Meloidogyne hapla, M. chitwoodi, M. fallax, and M. incognita Infestation. In: Plants (Basel, Switzerland) 13 (13), S. 1730. DOI: 10.3390/plants13131730. Noskov I, Blum H, Hallmann J (2024) Response of mint varieties from Central Europe (Mentha spp.) to Meloidogyne infestation. In: Journal of Applied Research on Medicinal and Aromatic Plants 42, S. 100561. DOI: 10.1016/j.jarmap.2024.100561.
Federal Ministry of Agriculture, Food and Regional Identity
