Wânia dos Santos Neves

Nematicidal activity of extracts of red hot chili pepper, mustard and garlic on Meloidogyne javanica in green house.

Neves, W.S; Freitas, L.G.; Coutinho, M.M.; Giaretta-Dallemole, R.; Fabry, C.F.S.; Dhingra, O.D. & Ferraz, S. Nematicidal activity of extracts of red hot chili pepper, mustard and garlic on Meloidogyne javanica in green house. Summa Phytopathologica, v.35, n.4, p.255-261, 2009 The experiment had the objectives of evaluate the nematicidal activity of botanical extracts of chili pepper fruits (Capsicum frutescens), mustard (Brassica campestris) and garlig (Allium sativum) on the root-knot nematode, Meloidogyne javanica in tomato plants in the greenhouse, and in a second step, to compare the best extracts for the reduction of the number of eggs and root galls with two products containing capsaicin, capsainoids and allyl isothiocyanate. A sieved mixture of soil and sand 1:1 (v:v) was used to fill plastic pots and infested with 4000 eggs of M. javanica. After 4 days, 20 mL of one of the extracts, in the concentration of 1000ppm, were poured over the soil of each pot. Water was poured in the test treatment. Twenty day-old tomato seedlings were planted, one per pot, four days after the aplication of the extracts. Forty five days after planting, the number of galls and eggs per plant was evaluated. The chloroformic and cetonic extracts of chili pepper and the mustard oil presented the highest effect on the nematode population, differing from the control treatment in respect to the number of galls, but only the mustard oil differed from the control in the number of eggs per plant. The chloroformic and cetonic extracts of chili pepper and the mustard oil reduced in 34,5%, 40,4% and 99,9% the number of galls, respectively, and the mustard oil reduced the number of eggs in 99,9%. In the following experiment, the chloroformic extract of chili pepper, the mustard oil, a commercial product (Champon®) and a product in development at the UFV called DS, both containing capsaicin, capsainoids and allyl isothiocyanate, were compared at different concentrations. The Champon®, the DS and the mustard oil reduced the egg and gall numbers in comparison with the control treatment in all the tested concentrations. The pepper extract show the best result at 400 ppm, reducing the number of galls and eggs per root system in relation to the control treatment, however, these numbers were much higher than the observed in the Champon® and the DS treatments.

Obtenção de bactérias para a o biocontrole de Meloidogyne javanica por meio de aquecimento de solo e tratamento com filtrado de raízes de plantas antagonistas a fitonematóides

Five samples of 1 kg each of organic soil (10.14 dag/kg) were autoclaved at 120 °C for 1 hour, five were heated in a 660 watt and 2450 Hz microwave oven at full power for 4 min, and five were not heat-treated. Roots of Mucuna aterrima, Crotalaria juncea, Tagetes erecta and Lycopersicon esculentum were macerated, separately, in 1000 ml of tap water in a blender at low speed for 30 s, then sieved. Each of the resulting suspensions or just tap water (control treatment) was poured on one of the different soil samples inside a plastic bag and stored at 28 °C for 24 h. Seventy-eight bacterial isolates were obtained from the soil samples by serial dilution and selected for a subsequent assay for the biocontrol of Meloidogyne javanica. Tomato seeds were soaked in suspension of each bacterial isolate, then sowed in substrate inside plastic tubes in the greenhouse. The seedlings were each inoculated with 400 eggs of the nematode. The isolate UFV-6 of Escherichia coli reduced the number of galls to the highest extent (80%), and UFV-8 of Citrobacter freundii was the most effective in reducing number of eggs (83%). The identification of the isolates was done by fatty acid analyses and biochemical tests.