EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS<br />
P126 - Study <strong>of</strong> the antagonistic effect <strong>of</strong> Trichoderma<br />
spp. against Fusarium spp. and M. nivale involved in<br />
Fusarium head blight and root rot <strong>of</strong> wheat.<br />
H. Boureghda, N. Abdellah, Y. Dane<br />
Département de Botanique- Ecole Nationale Supérieure Agronomique (ENSA)-El Harrach- Algiers-<br />
Algeria<br />
E-mail: hou.boureghda@gmail.com<br />
Three isolates belonging to the species T. atroviride (Ta.13), T. harzianum (Th. 6) and<br />
T. longibrachiatum (TL.9) were tested against six Fusarium species (F. culmorum, F.<br />
graminearum, F. avenaceum, F. lateritium, F. solani, F. verticilliodes) and M. nivale.<br />
Tests were carried out using in vitro and in vivo based bioassay. Evaluation <strong>of</strong><br />
antagonistic activity in vitro was performed using two techniques: direct and indirect<br />
confrontation. In the case <strong>of</strong> direct confrontation, a net reduction <strong>of</strong> the pathogen<br />
growth was observed with variability in the sensitivity <strong>of</strong> Fusarium spp. and M. nivale<br />
towards Trichoderma species and also on the effectiveness <strong>of</strong> Trichoderma species<br />
tested. Their effectiveness was evaluated by the percentage <strong>of</strong> the pathogen colony<br />
growth reduction which varied from 12.28% to 100%. The highest percentage growth<br />
reduction <strong>of</strong> all Fusarium species and M. nivale was obtained with the isolate Ta.13<br />
(T. atroviride) where a percentage <strong>of</strong> 100% was obtained with F. lateritium, F. solani<br />
and M. nivale species. Once more, in direct confrontation pathogens isolates colonies<br />
were invaded by Trichoderma with a variability <strong>of</strong> this behavior which varied from total<br />
recovery, partial or no recovery by the antagonist. In the case <strong>of</strong> Fusarium species,<br />
total or partial recovery with the species T. atroviride and T. longibrachiatum and no<br />
recovery with the species T. harzianum were observed. Nevertheless, a full recovery<br />
<strong>of</strong> the pathogen colony was observed for M. nivale with the three species T. atroviride<br />
(Ta.13), T. harzianum (Th.16) and T. longibrachiatum (TL.9). By using this technique,<br />
it was shown that M. nivale is the most sensitive species towards Trichoderma. In<br />
indirect confrontation (no direct contact) between the pathogen and the antagonist,<br />
where inhibition occurs only as a result <strong>of</strong> volatile antifungal substances produced by<br />
the antagonist, significant reductions on the pathogen growth compared to the control<br />
were obtained. Percentage <strong>of</strong> reduction varied between 5.05 and 74 .54%, and the<br />
highest percentages within Fusarium species were obtained with T. atroviride (Ta.13).<br />
Nevertheless for M. nivale, the highest percentage <strong>of</strong> reduction was obtained with T.<br />
longibrachiatum (TL.9). By in vivo bioassay, Ta.13 (T. atroviride) isolate which has<br />
been proved to be most effective in vitro test was assessed against the species F.<br />
culmorum by seed treatment before sowing wheat in soil infested with F. culmorum.<br />
As result, a percentage <strong>of</strong> inhibition <strong>of</strong> disease severity <strong>of</strong> 70.44% was obtained<br />
showing the effectiveness <strong>of</strong> this species in wheat protection against root rot and<br />
crown rot. In this study it was also shown the production <strong>of</strong> antifungal volatile 6PP (6pentyl-α-pyrone)<br />
by Ta.13 and that this isolate is a major producer <strong>of</strong> 6PP.<br />
Keywords: Fusarium spp. direct confrontation, indirect confrontation, 6PP<br />
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