Evaluation of Trichoderma spp. for the control of damping-off of tobacco
1991
Dipon, P.N. | Salinas, M. (Eastern Philippines Univ., Catarman, North Samar (Philippines))
The potential of seven species of Trichoderma for controlling damping-off was studied in the laboratory and greenhouse. Growth of surface mycelium of Fusarium oxysporum f. sp. nicotianae, Sclerotium rolfsii, and Pythium aphanidermatum were severely inhibited by T. hamatum, T. harzianum, and T. aureoviride. These antagonists overgrew the pathogens and covered the entire portion of the culture plate 10 days after incubation. T. hamatum and Trichoderma sp. (Batac isolate 1) were antagonistic (overgrew at least two-thirds of the medium surface) against F.O. nicotianae and S. rolfsii, but not against F. aphanidermatum. Greenhouse evaluation using T. harzianum and soil naturally infected with the disease showed that tobacco damping-off could be satisfactorily controlled up to a period of 30 days after sowing (DAS). Infection in treated soil was 35% at 15 DAS (pre-emergence damping-off) and 58% in transplantable seedlings (30 DAS). Without the antagonist, infection of 58% at 15 DAS and 75% at 30 DAS were obtained. The high incidence of damping-off during the post-emergence phase of the disease may indicate that the antagonist alone could not contain the disease. Very few seedlings survived at 70 DAS, 40 to 73 seedlings in treated soil and 25 in the control.
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