Efficacité au champ de l’ANTRACOL 70 WP, un fongicide à base du Propineb 70%, sous pression naturelle de l’helminthosporiose du riz due à <I>Bipolaris oryzae</I>

L’helminthosporiose est l’une des maladies fongiques majeures, a l’origine des pertes de production rizicole en Cote d’Ivoire. Dans le but de reduire ces pertes, une etude portant sur l’evaluation de l’efficacite du fongicide ANTRACOL 70 WP (Propineb 70%) a ete realisee sous pression naturelle de maladie. Trois doses du fongicide ANTRACOL 70 WP (1,5 kg ha-1, 2 kg ha-1, 2,5 kg ha-1) et une dose du fongicide de reference COGA 80 WP (mancozebe, 800 g/kg) a 2 kg ha-1 ont ete evaluees. Les resultats obtenus ont montre que les gains de rendement dus a l’utilisation du fongicide sont en moyenne de 80,05%. La note de severite (2) enregistree dans la parcelle traitee avec l’ANTRACOL 70 WP a ete identique a celle obtenue dans la parcelle traitee au COGA 80 WP. Ce resultat montre que l’ANTRACOL 70 WP a ete efficace contre l’helminthosporiose du riz. Les rendements en paddy acquis sous les differents traitements fongicides ont montre qu’a la dose de 2,5 kg ha-1, l’ANTRACOL 70 WP a permis de doubler au moins le rendement en paddy (2,72 t ha-1) par rapport aux parcelles traitee au COGA (1,36 t ha-1) et non traitee au fongicide (0,89 t ha-1).Mots cles : Riz pluvial, helminthosporiose, severite, ANTRACOL 70 WP, Cote d’Ivoire. English Title: Field efficacy of ANTRACOL 70 WP, a fungicide based on Propineb 70%, under natural pressure of rice leaf brown spot disease caused by Bipolaris oryzaeBrown spot is one of the major fungus diseases inducing yield losses of rice in Cote d’Ivoire. In order to reduce those losses, a study to assess the effectiveness of the fungicide ANTRACOL 70 WP (propineb 70%) was carried out under disease natural pressure. Three doses of the fungicide ANTRACOL 70 WP (1.5 kg ha-1, 2 kg ha-1, 2.5 kg ha-1) and a recommended dose of a reference fungicide COGA 80 WP (mancozeb, 800 g / kg) at 2 kg ha-1 were evaluated. The results obtained showed that the average yield gains due to the use of this fungicide was 80,05%. The severity score recorded in the plot treated with ANTRACOL 70 WP (note = 2) was identical to that obtained in the plot treated with COGA 80 WP. This result shows that ANTRACOL 70 WP was effective against brown spot disease of rice. The paddy yields recorded under the various fungicidal treatments have shown that at a dose of 2.5 kg ha-1, the ANTRACOL 70 WP allowed to at least double the paddy yield (2.72 t ha-1) compared to plots treated with COGA (1.36 t ha-1) and not treated with fungicide (0.89 t ha-1).Keywords: Rainfed rice, brown spot disease, severity, ANTRACOL 70 WP, Cote d´Ivoire.