SENSIBILITE DE MYCOSPHAERELLA FIJIENSIS AUX DIFFERENTES MATIERES ACTIVES FONGICIDES UTILISEES EN BANANERAIES CONTRE LA MALADIE DES RAIES NOIRES EN COTE DIVOIRE DE 2016 A 2017

Mycosphaerella fijiensis sensitivity was evaluated with samples of banana leaves Grand Nain with conidia and collected in twelve industrials plantations covering 3059 ha. In the laboratory observations on sampled conidia were made 48 hours after their incubation on agar amended fungicides (methyl thiophanate 5 ppm, tebuconazole, difenoconazole and epoxiconazole at 0.003 0.01 0.1 and 1 ppm and azoxystrobin 1 and 10 ppm and trifloxystrobin 0.1 and 3 ppm). The observations were made under a microscope and consisted in determining the normal germinating conidia rate (benzimidazoles) and the growth inhibition rates of the germ tube of conidia (triazoles and strobilurins). From these observations the existence of resistance to triazoles used in most plantations except Rouchard (31%), ELIMA (28%), EGLIN Agboville (34%), SPDCie (33%), Batia (34%) and Siapa (34%) of tebuconazole, and Rouchard (29%) for epoxiconazole. For strobilurins only mushroom DICONNE (81%) and AKRESSI (78%) were resistant to Trifloxystrobin then DICONNE (83%) for azoxystrobin. But for the benzimidazoles resistant strains of fungus was observed in all sampled plantations.