Integrated nematode management options in bananas and reduction of pesticides

In the Caribbean, as in central and south America, nematodes, and particularly the burrowing nematode Radopholus similis, are one of the three main key pests against which pesticides were applied for decades on bananas from the Cavendish group. Because of its lower capacity to survive outside from its host, R. similis can be controlled by cropping systems that combine fallows or crop rotations. The nematode-free planting materials (certified vitro-plants) and the control of runoff water are efficient methods to prevent the field re-contamination by nematodes for more than 5 years. The generalization of this cropping system has allowed Martinican farmers to reduce their nematicide application by 97 % while improving their productivity. However, the black leaf streak disease (BLSD) is expanding; due to societal pressure, the aerial disease control using fungicides application is more and more questioned. The long term solution is the development of banana varieties resistant to BLSD. However, these varieties can be susceptible to other nematode species, such as Pratylenchus coffeae, which is endemic and more difficult to control than R. similis. P. coffeae is moreover much more frequent in plantain fields than R. similis. Thus, complementary methods of nematode control have to be developed. Besides the weed control, the cover plants can improve the soil biodiversity, particularly the diversity of free-living nematodes. These nematodes, specially the predators, can directly or indirectly contribute to the regulation of plant-feeding nematodes. A better knowledge of food-webs that involve nematodes may contribute to the development of methods of biological control. Studies on the reactions of plants to the parasitic attacks can result in the improvement of self induced resistances. From the overall combination of these methods, new cropping systems should be tested for a more sustainable production, towards a pesticide-free banana production. (Texte intégral