Avaliação da competição entre Meloidogyne incognita e M. enterolobii inoculados em olerícolas

Abstract

All around the world there are, at least, one hundred species of the root-knot nematode, Meloidogyne Goeldi. In Brazil, at least fifteen species of this nematode are registered, in which five are considered to be the most important affecting the cultures in the country. It’s important to highlight M. incognita and M. enterolobii, both very disseminated in cultivation areas of fruit trees and vegetables, where they cause considerable damage. To M. enterolobii is attributed an even bigger agressivity for infecting vegetal material resistant to Meloidogyne spp. In general, there is not too much information about the plants’ reaction when infested simultaneously by two nematodes of same kind, as well as little is known about the nematodes behavior which compete for the same host. Therefore, the aim of this work is to evaluate the effects resultant of simple and combined infections of M. incognita (Mi) and M. enterolobii (Me), about cultivating ‘Carolina’ tomato and also to evaluate the resistance of ‘Chato de Quintal’ cabbage to the mentioned nematodes. The essay was conducted in greenhouse (31 + 4°C) and in UFC’s Phytopathology laboratory. Seeds from the two cultivations in the stage of four leaves were transferred individually to vases with autoclavable soil and, after five days, inoculated with 3.000 eggs/J2 of each nematode species. The lineation chosen was entirely causalized with 9 treatments: 1- inoculation of Mi in tomato (Mi + Me); 2- inoculation of Me in tomato; 3- inoculation of Mi followed by Me’s; 4- inoculation of Me followed by Mi’s; 5- simultaneous inoculation (Mi + Me); 6- inoculation of Mi in cabbage; 7- inoculation of Me in cabbage; 8- cabbage not inoculated; 9- not inoculated tomato. After 45 days of inoculation, the plants were subjected to evaluation of number of rootknots, eggs’ mass in roots and the factor of reproduction to determine the level of infection of each species. Females removed from the radicular system were subjected to electrophoresis of isoenzymes to determine the predominat species in the tomato cultivation. The isoenzymes electrophoresis technique proved the predominance of M. enterolobii over M. incognita, no matter the inoculation order, suggesting its bigger agressivity, in spite of not being confirmed the raise of its population. The evaluation showed that the ‘Chato de Quintal’ cabbage, of known resistance to M. enterolobii, is also resistant to M. incognita.