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Susana Beatriz Martínez

UNLP/UNNOBA (National University of La Plata / National University of Northwestern Buenos Aires), Argentina

Title: Phytohormones: use for the control of Nacobbus aberrans in tomato (Solanum Lycopersicum .L)

Abstract

In Argentina, phytonematodes cause important losses in tomato; for that reason, it is important to look for sustainable alternatives to methyl bromide. Phytohormones such as salicylic acid (AS), jasmonic acid (AJ) and ethylene (E) are involved in growth processes and inductions of defenses against biotic adversities. In order to evaluate the effect of these phytohormones on the growth, production, and control of Nacobbus aberrans in tomato, three trials were conducted in a greenhouse located in the city of La Plata, Argentina (33º56'42.6”S, 60º33'35.6 ”W), using the hybrid F1 Elpida (Enza saden®). To adjust the concentration of phytohormones, it was evaluated the effect of three concentrations of each trial (AS50: 0.5.10-4 M; AS100: 1.0.10-4 M; AS200: 2.0.10-4 M; AJ-3: 1 00.10-3M, AJ-4: 1.00.10-4M, AJ-5: 1.00.10-5M, E50: 0.35.10-3M, E100: 0.70.10-3M, E200: 1, 40.10-3 M, T0: control) on relative growth. The plants were grown in pots with substrate; some were artificially infested with N. aberrans whereas others had no infestation. Hormones to the substrate in the germination tray (1 ml per cell) were applied to all the plants. Six concentrations were selected: AS50, AS100, E100, 4AJ-4, AJ-5, E50 and T0, with which the effect of pre-transplant application time (24, 72 and 168 hours) on relative growth was evaluated under the same conditions as the previous trial, without observing significant differences between treatments. 

This trial was repeated 24 hours before transplantation, applying the same concentrations, without observing significant differences in growth variables, but with a significant reduction in the number of galls produced by N. aberrans on the root, gall index and reproduction in treated plants, particularly when use AS100. In a similar trial conducted in naturally infested soil with 48 J3 and J4 of N. aberrans, among other nematodes, AS100 stood out from the rest, with zero rate of galling and reproduction, without affecting plant growth and improving overall yield of the crop (21.6 kg.m-2).

Biography

Susana Martínez has completed her PhD at National University of La Plata, Argentina. She is the Director of the Department of Environment and Natural Resources of the Faculty of Agricultural and Forestry Sciences (University of La Plata, Argentina). She is also the Director of the Vegetal Bioclimate Laboratory and of the post grade ‘Specialisation in Protected Crops’, and Professor of Climatology and Agricultural Phenology and Horticulture and Floriculture (UNLP / UNNOBA). She has published more than 200 publications, and has trained a large number of graduates in her field of study. She has devoted her professional life to the academic world and has become an international consultant.