Introduction. Bananas are harvestedat the green preclimacteric stage prior to sale. The time betweenharvest and the initiation of the natural ripening process is calledgreen life. Black Leaf Streak Disease and Sigatoka Disease are themain foliar diseases affecting banana production. Sigatoka Disease (SD)is due to Mycosphaerella musicola, which frequently causesearly ripening in commercial banana plantations, considered as animportant source of damage. Our work aimed at determining the effectivenessof the removal of necrotic leaves, one month before harvest, onrecovering banana quality arising from SD-infested plants. Materialsand methods. Banana plants (totaling 80) at the floweringstage were selected in an experimental plot. These plants were dividedinto two groups of SD infestation levels: level 1 (Severity Indexat flowering < 10%) and level 2 (Severity Index at flowering > 25%).We divided each group into two treatments: a treatment with no necroticleaf removal and a treatment with necrotic leaf removal. Fruitswere harvested at the same physiological age, at 900 degree-days. Fruitquality was characterized by weight, diameter, % of ripe fruit inthe field and fruit green life. Results. Our resultsshowed that the removal of necrotic leaves causes a reduction insize parameters but leads to a strong reduction in SD effects onthe fruit maturity, thereby preventing premature ripening. Bananaplants whose necrotic leaves were removed produced fruit with a verylong green life. Discussion. Removal of necrotic leaves allowsthwarting the negative effect of SD on fruit physiology. This showsthat the presence of necrosis during the last month of fruit growth isresponsible for this fruit physiological modification characterizedby early ripening. Conclusion. Removal of necroticleaves one month before the date of harvest may be a technique thatcan limit production losses when the infestation level by SD ishigh.

Introduction. Black Leaf Streak Disease (BLSD) is regarded as the mosteconomically important threat that the banana industry has to face. Effectively, thisfoliar disease affects leaf photosynthesis but, above all, reduces the greenlife offruits, that cannot be exported in cases of severe infestation. Main characteristicsof Black Leaf Streak Disease. More than 20 Mycosphaerellaspecies have been described on bananas. Leaf spot diseases of bananas are causedby some species of this complex, of which M. fijiensis (BLSD) andM. musicola (Sigatoka disease) are the most important. M.fijiensis is an invasive species that has totally replaced M. musicolain most banana-exporting countries, which was conducive to increasingdifficulties in banana leaf spot control. BLSD causes increasing difficulties forcontrol. Since all banana cultivars grown in the banana industry are highlysusceptible to BLSD, the control of this disease relies on aerial applications offungicides according to either systematic frameworks (mostly contact fungicides) orforecasting strategies (mostly systemic fungicides). In a banana-exporting country whereM. fijiensis has been reported, BLSD control becomes increasingly moredifficult. This evolution is essentially due to the rapid emergence of fungicideresistance, and is conducive to a significant increase in the cost of disease control but,above all, to increasing negative environmental effects. Challenges for the bananaindustry. Because of the rapid adaptation of M. fijiensis, thebanana industry must be prepared for significant evolution. We propose various parametersthat should be monitored at different levels (disease assessment parameters, evaluation ofchemical control efficiency, global evaluation of BLSD economic incidence) to rationalizesuch evolution. The modelization of BLSD effects on bunch mass and greenlife should enabledefining acceptable disease thresholds and optimizing bunch weight and harvest stageaccording to agronomic practices. On the other hand, fungicide use is conducive tosignificant environmental impact and must be limited. Forecasting strategies should beused wherever systemic fungicides are still efficient. Finally, the predominance of aunique type of susceptible cultivar is unsustainable and the recourse to resistantvarieties in an integrated strategy is undoubtedly the future of BLSD control.

Introduction. This protocol aims to diagnose under laboratory conditions the main Mycosphaerella spp. pathogens of bananas and plantains. The three pathogens Mycosphaerella fijiensis (anamorph Paracercospora fijiensis), M. musicola (anamorph Pseudocercospora musae) and M. eumusae (anamorph Pseudocercospora eumusae) are, respectively, the causal agents of Black Leaf Streak disease, Sigatoka disease and Eumusae Leaf Spot disease. The principle, key advantages, starting plant material and time required for the method are presented. Materials and methods. The laboratory materials required and details of the thirteen steps of the protocols (tissue clearing and in situ microscopic observations, isolation on artificial medium and cloning of single-spore isolate, in vitro sporulation and microscopic observations of conidia, and long-term storage of isolates) are described. Results. Diagnosis is based on the observations of anamorphs (conidiophores and conidia) which can be observed directly from banana leaves or after sporulation of cultivated isolates if sporulating lesions are not present on banana samples.

Introduction. This protocol aims at (i) analysing the nature of host-parasite interactions (resistance or susceptibility), and (ii) studying the variability of the pathogenicity of different pathogen populations (intra/inter-specific) with regard to both virulence and aggressiveness using artificial inoculation with Mycosphaerella fijiensis or Mycosphaerella musicola on plants and banana leaf pieces. The principle, key advantages, starting plant material and time required for the method are presented. Materials and methods. Laboratory materials required and details of the sixteen steps of the protocol (conidial inoculum preparation, artificial inoculation on banana plants and artificial inoculation on banana leaf pieces) are described. Possible troubleshooting is discussed. Results. Typical symptoms of the different diseases are obtained after artificial inoculation.

Introduction. Le plantain est une culture importante pour la sécurité alimentaire en Afrique sub-saharienne. Pour mieux hiérarchiser les priorités de recherche en fonction des contraintes des producteurs, une cellule d'observation permanente a été mise en place dans le cadre d'une démarche interdisciplinaire. Matériel et méthodes. Un échantillonnage en bananeraies a couvert les zones de contextes agroécologiques distincts qui approvisionnent Douala. Les données ont été obtenues par un suivi de parcelles et d'exploitations. À l'échelle des parcelles, les observations ont porté sur les pratiques culturales, les populations de nématodes et de charançons, et les rendements. À l'échelle des exploitations, les suivis ont porté sur les fonctions économiques du plantain. Résultats et discussions. La gamme de situations culturales étudiées correspond à une diversité de contextes et d'objectifs des exploitations agricoles. Les observations effectuées sur bananiers (rythme d'émission foliaire, circonférence du pseudotronc, nombre de doigts et de feuilles vivantes, poids et longueur des doigts, poids du régime) ont permis d'expliquer comment se déterminait le rendement. Celui-ci est surtout affecté par les pertes avant récolte, en relation avec l'état sanitaire des racines et la présence de nématodes et de charançons. Ces pertes ont été maximales à la fin de la saison sèche. Le rendement est également lié au poids du régime déterminé par le nombre de doigts essentiellement lié à la croissance et à leur remplissage. Pour ce dernier caractère, les résultats obtenus ne mettent pas clairement en évidence l'incidence de la maladie des raies noires. Des améliorations du protocole de suivi sont proposées.

This article reviews progress in extensive survey work using satellite photographs along the course of the reservoir of the Birecik dam, completed in June 2000. Particular attention has been paid during field work to routes both along and across the river; here it is the east-west routes crossing the river which are examined in detail and in the context of the region's historical geography. The city of Zeugma, which has been the object of recent excavations, was the principal such crossing point but by no means the only one on the middle course of the Euphrates. A subsequent article will discuss north-south routes in the vicinity of the middle Euphrates and the question of its navigability.