Recent advances in organic cultivation of chayote (Sechium edule) in Reunion Island

In Reunion Island, the cultivation of chayote is a heritage culture, which has been practiced intensively in recent decades, with large utilisation of mineral fertilizers and pesticides. This situation paradoxically led to significant production losses due to fruit shedding and damage of Fruit Flies (Tephritidae). For the last ten years, the actors of agriculture in Reunion Island have worked to ensure the transition from an agrochemical cultivation of chayote to an agroecological one, compatible with the Organic Farming regulations. From 2009 to 2012, a Research & Development project was carried out to implement cultural practices allowing chayote organic cultivation. Since 2012, extension agencies as well as public authorities have multiplied initiatives to develop the surfaces of chayote under organic cultivation. In 2017, more than 6 0% of the chayote areas are cultivated according to the O Fregulations. New and original knowledge has been acquired on the biology and ecology of Fruit Flies. Sanitation against fruit flies using the augmentorium technique and the establishment of a permanent vegetal cover under chayote trellises were quickly adopted by the farmers. Fruit damage was severely limited, resulting in increased yields (+ 48% in a multi - year yield comparison over 7.6 ha between 2007 and 2011). The protection has been estimated to be at least four times cheaper, and the time of protection has been reduced by 9%. The use of mineral fertilizers and pesticides has been eliminated. After the experimental phase, tools for transferring knowledge and techniques have been designed and developed while three types of financial incentive measures have been offered to chayote growers under organic standards. The experience of the development of organic chayote cultivation is the first one at this large scale in Reunion Island. It has allowed the identification of generic determinants of agroecological innovations for their adoption by producers. It also has contribute d to the development of organic farming in other crops (i.e. mango, citrus) and to adaptations of these agroecological practices in neighboring countries in the Indian Ocean. (Resume d'auteur)