Abstract
In the case of amelioration and black cigatoka management on
banana in our region. This study had as an object to study the diversity of
black cigatoka on banana in Walungu and Kabare territories. An inquiry was done
in Walungu (Izege, Ikoma, Walungu center, Mushinga, Nyangezi, Irhongo, Burhale
and the collectivity of Kaziba) and in Kabare (at Katana, Bushumba, Miti,
Mudaka, Mumosho, Bugorhe, Mudusa and Chirunga). It was a question of
determining the incidence and severity of black cigatoka on banana, evaluate
means to fight utilize by peasants and to harvest some leaves which present the
symptoms of this disease by morphologic characterization and the execution of
pathogenicity test. An inquiry questionnaire was used and the observation of
plants infected also to have some informations on varieties and diseases and
the determination of the incidence and severity. The isolation of
Mycosphaerella fijiensis on a PDA environment and the microscopic
observation was realized in biomolecular laboratory at U.E.A. pathogenitic test
was done under hothouse on three varieties (FHIA17, NARITA4 and NARITA13) from
Burundi at BioTechnological laboratory. After analyses, the following results
were observed: the disease presents a sturdy incidence and severity (seventy
one dots nine) a Walungu and forty one dot nine at Kabare. Six isolators were
identified (M. fijiensisBAR-KAT, M.
fijiensisKIS-WAL, M. fijiensisGRO- BUSH,
M. fijiensisMUSH-MUM,
M. fijiensisNAK-IKO and M.
fijiensisKAM-IZE) and have presented some typics morphologic
characteristics at M. fijiensis. For the evaluation of pathogenic
ability two isolating was utilized over two territories at the first have
showed a pathogenic ability against NARITA4 and NARITA13. M.
fijiensisKIS-WAL was very virulent than M.
fijiensisBAR-KAT. The two insulants have presented
some typics symptoms of black cigatoka but FHIA17 has presented a resistance on
two insulants, on hothouse the two insulants of M. fijiensis has
presented a high incidences and they were very severe. Seeing that we recommend
to others researchers that one study on molecular characterization of
Mycosphaerella fijiensis should be realized to evaluate the genetic
variability of insulants at Kabare and Walungu, those informations should be
diffused nearby the paysans to improve their knowledge on black cigatoka
stuggle on banana.
Key words: Black cigatoka, epidemiology, diversity, Banana,
Walungu and Kabare.
VIII
Listes des tableaux et figures
Tableau 1 : Les variétés/cultivars
rencontrées à Walungu et Kabare 19
Tableau 2 : Moyens de gestion des bananeraies 21
Tableau 3 : Susceptibilité des cultivars à la
cercosporiose noire du bananier quant aux paysans
dans le Walungu et Kabare 22
Tableau 4 : Incidence et sévérité de la
cercosporiose noire du bananier 23
Tableau 5 : Les dénominations des isolats
rencontrés 24
Tableau 6 : La couleur, la forme des mycéliums de
différents isolats et la couleur du fond de la
boite de pétrie. 27
Tableau 7. Le taux de développement de la maladie par
jour 30
Fig. 1 : Stades de développement de la
cercosporiose noire en champs d'après Fouré (1982) .... 7
Fig. 2 : Conidiophore et conidies (A) ; Spermogonie et
spermaties (B) ; périthèce, asques et
ascospores (C) de M. fijiensis (Onautshu et al., 2013).
8
Fig. 3 : Le cycle infectieux de M. fijiensis (Carlier,
2010). 9
Fig. 4 : les morceaux de feuilles avec symptômes de
M. fijiensis dans la boite de pétrie 15
Fig. 5 : Dispositif expérimental en block
complètement aléatoire avec trois répétitions
16
Fig. 6 : Les maladies rencontrées sur les bananiers
dans le Walungu et Kabare 20
Fig. 7 : Nombre de cloisons des conidies des isolats de M.
fijiensis 25
Fig. 8 : La structure des ascospores observés sur
microscope optique agrandis 40x. 25
Fig. 9 : La croissance mycélienne des
différents isolats de M. fijiensis 26
Fig. 10 : La coloration noire de M. fijiensis à la
face inferieure de la boite de pétrie. 28
Fig. 11 : symptômes de M. fijiensis en serre
29
Fig.12 : Sensibilité de différentes
variétés face à M.
fijiensisKIS-WAL et M. fijiensisBAR-KAT
29
Fig. 13 : L'indice de sévérité de la
MRN pour les différentes variétés 30
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