Induction of resistance towards bacterial pathogens of tomato by exposure of the host to dinitroaniline herbicides

Cohen, R.; Cuppels, D.A.; Brammall, R.A.; Lazarovits, G.

Induction of resistance towards bacterial pathogens of tomato by exposure of the host to dinitroaniline herbicides

1992

Cohen, R. | Cuppels, D.A. | Brammall, R.A. | Lazarovits, G.

Growth of tomato seedlings (cv. Bonny Best) in rooting substrate amended with the dinitroaniline herbicide, dinitramine (1 ppm in sand/Pro-mix, 1:1 or 1:2, v/v), caused a suppression in bacterial wilt symptoms caused by the Pseudomonas solanacearum strain K60. Dinitramine was not inhibitory to P. solanacearum in in vitro assays nor did it restrict multiplication of the pathogen in treated plants. Dinitramine also caused a decrease in the severity of bacterial canker, caused by Clavibacter michiganense subsp. michiganense JD83-1, but had no significant effect on the severity of bacterial speck, caused by Pseudomonas syringae pv. tomato DC894H. Resistance was not induced by a similar exposure of plants to the herbicides ethalfluralin or oryzalin. Resistance to Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, was induced by exposure of seedlings to the herbicides dinitramine, ethalfluralin, and oryzalin. Acetochlor induced resistance towards Fusarium wilt but did not towards bacterial wilt. Exposure of plants to the dinitroaniline herbicide, trifluralin, did not induce resistance towards either bacterial wilt or Fusarium wilt in our experiments.

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