An early quantification method of quiescent infections of Colletotrichum musae on bananas using ethylene treatment

Anthracnose is the main post-harvest disease of bananas grown in the French West Indies. Colletotrichum musse, the causal agent, forms quiescent infections on the fruit peel that lead to necrosis at maturity. The existence of quiescent infections makes it impossible to assess the inoculum level on the fruit peel before the ripening of the banana. The development of a technique to quantify the inoculum level on the fruit before harvest would be very interesting for banana growers; it can lead them for certain technical decision such as whether or not to apply fungicides after harvest. This work has been done to determine a practical method, usable in routine, to quantify the inoculum level on mature and immature fruit, so that it can be used as a method of early prediction. Two points have to be considered: - breaking the dormancy of the appressoria, - the non apparition of senescent spots. After the elaboration of the method, we have considered the role of the ethylene treatment as the primary determinant of the breaking of the dormancy of the appressoria. (Résumé d'auteur