EFFECTIVENESS OF FUMIGANTS ALONE AND IN COMBINATION WITH GRAFTING TO CONTROL VERTICILLIUM WILT AND ROOT-KNOT NEMATODES IN EGGPLANT AND TOMATO BROWN ROOT ROT CAUSED BY COLLETOTRICHUM COCCODES

The use of chemical compounds and especially fumigants is still an effective method to control high infestation levels of soilborne pathogens, pests and weeds.
A series of trials has been carried in 2005-2006 out considering the problems related to incomplete resistance of grafted eggplants against Verticillium dahliae and the only partial activity of available fumigants against V. dahliae and Meloidogyne incognita. Dimethyl disulfide (DMDS) alone (30, 40, 60, 80 g a.i. m^-2) and DMDS at 35, 30 and 20 g a.i. m^-2 in mixture respectively with chloropicrin at 5, 10 and 20 g a.i. m^-2 were evaluated in comparison with chloropicrin (CP) alone at 20 g a.i. m^-2 and the mixture of 1,3-dichloropropene (1,3-D) at 20 g a.i. m^-2 + chloropicrin (20 g a.i. m^-2-2). The fumigants were applied under VIF films by drip irrigation (40 mm of water). One month after the treatments, eggplants (‘Prosperosa’) were transplanted into the fumigated beds.
The effectiveness of different treatments on the percentage of dead plants as a consequence of combined attacks of V. dahliae and root-knot nematodes was evaluated during the cropping season.
In the presence of a very high infestation of the soil by both parasites, the best results were provided by the mixture DMDS+CP applied respectively at 20+20 g a.i. m^-2 and 30+10 g a.i. m^-2, also in terms of marketable eggplant fruit weight.
The DMDS+CP mixture performed better than 1,3-D+CP, probably because of a lower activity of CP against V. dahliae when used at 20 g a.i. m^-2. DMDS used alone showed a good activity only at high dosages (80 g m^-2). In a second set of trials, in an attempt to find effective control measures against Colletotrichum coccodes, an emerging pathogen causing root rot on tomato in northern Italy, four experimental trials were carried out during the years 2005 and 2006 in order to evaluate the effectiveness of the combination of different rootstocks (‘Beaufort F1’, ‘He-Man F1’, ‘Maxifort’) with metham-sodium (MS), CP alone and combined with DMDS (20+20 g a.i. m^-2) and DMDS at 20, 40 and 80 g a.i. m^-2. In the presence of medium to high disease incidence, the best results were obtained by combining the use of a resistant tomato rootstock with DMDS at 40 or 80 g a.i. m^-2 or MS at 192 g a.i. m^-2. CP applied at 20 g a.i. m^-2, and the tested rootstocks alone, did not allow effective control of the pathogen.

VII International Symposium on Chemical and Non-Chemical Soil and Substrate Disinfestation

G. Gilardi, M.L. Gullino, A. Garibaldi, M. Baudino

integrated disease management, soilborne pathogens, resistant rootstock

https://doi.org/10.17660/ActaHortic.2010.883.21