Biological control of nematodes in banana.

Several species of nematodes are associated with banana and plantain in Cuba; however, the most important are Radopholus similis, Meloidogyne incognita, Pratylenchus coffeae and Helicotylenchus multicinctus. These parasites have been dealt with for several years using integrated management systems. These systems include legal, cultural, genetic, biological and even chemical measures that have been adapted to the different development stages in this crop. Biological control has shown to be an effective alternative that can be combined with others within an Integrated Management System. The base for biological control is the use of fungi such as Paecylomices lilacinus and bacteria such as Bacillus thuringiensis var. kurstaki. More recently, Corynebacterium paurometabolum bacterium has been added to this group as well as mycorrhiza from the Glomus genus. P. lilacinus was the first bioregulator of banana parasitic nematodes researched in the country. Its effectiveness was demonstrated under semicontrolled, in vitro conditions, and in the field. B. thuringiensis var. kurstaki (LBT 3 strain) is a bacterium effective against insects that has also nematicidal effects, mainly against R. similis. It was possible to determine that its applications under pot and field conditions significantly reduced nematode attack. Evaluation of its effectiveness in more than 185 ha of production fields revealed average reductions of 87% in plantations with different populations. Studies with C. paurometabolum (C-294 strain) showed that it has effects on eggs and juveniles, manifested both under laboratory and field conditions. Reduction of populations under controlled conditions exceeded 85%, while in the field, R. similis populations started to decrease after the application and stayed low during the experiment, showing results comparable with the nematicide used as control. With regards to mycorrhiza, early inoculation of in vitro plants at the hardening stage, with several species of the Glomus genus, minimized damage caused by R. similis and M. incognita.