POSSIBILITY OF BIOLOGICAL CONTROL AGAINST FUSARIUM OXYSPORUM DIANTHI

The antagonistic effect of 3 strains of Fusarium oxysporum wilt of carnation was studied. Two were isolated by Alabouvette from a suppressive soil to F.o.melonis: 47 and 20. The other isolated from perlite used as a substrate for soilless culture of carnation: TF3 is without relation with suppressive soil.

Incorporated in perlite before planting, their efficiencies vary for strains 47 and 20 according to the inoculum preparation. With a talcum inoculum the average of the diseased plants, after one year, is about 15% instead of 49% in the control; with a "powder" inoculum issued from a bran-perlite medium, they were not significantly different from the control. The effect of TF3 is independant of the nature of the inoculum in perlite and always positive, from 8.3 to 16.6% of wilted plants against more than 40% in the controls, but its efficiency is lower in soil naturally infected, with only half the reduction in number of diseased plants.