THE RELATION OF SOIL TYPE TO SUPPRESSION OF FUSARIUM WILT OF CARNATION

G.Y. Yuen, A.H. McCain, M.N. Schroth
The severity of carnation wilt caused by Fusarium oxysporum f. sp. dianthi was reduced by incorporating two wilt-suppressive soils into pathogen-infested potting mix at a rate of 5% w/w. Disease severity was reduced 30% below the control at the end of 5 months. Two wilt-conducive soils added at the same rate did not affect disease severity. Disease severity was similarly reduced by dipping roots of carnation cuttings into suspensions of these suppressive soils prior to planting. Ten different soils from the Salinas Valley in California were screened for their capacity to suppress Fusarium wilt using the root-dip method. All of the soils reduced wilt severity below the control by at least 25% at the end of 5 months, with six soils reducing wilt severity by over 50%. Rhizosphere bacteria isolated from suppressive soils reduced wilt severity by more than 40% when applied as suspensions to carnation roots prior to transplanting. The bacteria effectively reduced wilt for 4 months while suppressive soil treatments were effective for over 7 months. The duration of wilt protection by bacteria was related to the time that the applied bacteria were detectable in the rhizosphere of treated plants. One bacterium was applied to carnations planted in six soils of different textures and pH. Over a 4-month period, greater numbers of the bacterium were reisolated from plants grown in the fine-textured, neutral-pH soils than from plants grown in the sandy, acidic soils.
Yuen, G.Y., McCain, A.H. and Schroth, M.N. (1983). THE RELATION OF SOIL TYPE TO SUPPRESSION OF FUSARIUM WILT OF CARNATION. Acta Hortic. 141, 95-102
DOI: 10.17660/ActaHortic.1983.141.13
https://doi.org/10.17660/ActaHortic.1983.141.13

Acta Horticulturae