Screening of the nematicidal potential of some spice extracts against root-knot nematode, Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 (Tylenchida: Meloidogynidae)

Abstract

Experiments were conducted in the laboratories and greenhouses of Plant Protection Department, Agricultural Faculty, Ondokuz Mayıs University in 2018 and 2019 to investigate the nematicidal effects of aqueous extracts of 13 spices on Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 (Tylenchida: Meloidogynidae). Spice extract concentrations of 0.5, 1 and 2% were tested in laboratory experiments for inhibition of egg hatching, mortality and immobility of second-stage juveniles (J2s). When used at a concentration of 2%, clove, Syzygium aromaticum L. (Myrtales: Myrtaceae) caused the greatest immobility and mortality of J2s. The extracts had a lesser effect on J2s than the egg hatching. For the pot experiment, five effective spices extracts were selected based on the laboratory experiments. These extracts were applied at 2% to 200 g of soil inoculated with 3,000 nematode eggs then susceptible tomato seedlings were transplanted into the soil. Forty-five days after inoculation, the gall index and the quantity of nematode eggs on roots were determined and reproduction factor of nematode calculated. All extracts, except cumin, Cuminum cyminum L. (Apiales: Apiaceae), reduced root gall index and the reproduction factor when compared to control. Basil, Ocimum basilicum L. (Lamiales: Lamiaceae) extract reduced nematode reproduction the greatest degree, followed by turmeric, Curcuma longa L. (Zingiberales: Zingiberaceae) and clove extracts.