Reprodução e distribuição de nematoides do gênero Meloidogyne em canaviais de Pernambuco e Paraíba

Abstract

Considering Meloidogyne incognita and M. javanica importance for sugarcane and reports of M. enterolobii in the crop in Northeastern Brazil, this study had as objective identifying through biochemical methods the species of Meloidogyne occurring in sugarcane fields of Pernambuco and Paraíba States and evaluating reproduction of this three species in association or individually on the variety RB 867515. It was identified 19 nematode populations, mostly constituted exclusively by M. incognita phenotype I1(Rm: 1.0) and I2 (Rm: 1.0, 1.1). Meloidogyne incognita, M. javanica and M. enterolobii, in association or individually, did not affect plant growth variables. RB 867515 was a good host for M. incognita and M. javanica, but not for M. enterolobii, permitting free reproductions for the former nematodes. Esterease phenotypes at the end of the experiment presented quantitative variations in the species ratios used for inoculation, indicating M. incognita prevalence over the other species. The second study evaluated Meloidogyne enterolobii penetration, development and life cycle length on sugarcane variety RB 98710 as well the reaction of the variety to the nematode parasitism. After soil infestation with M. enterolobii and M. javanica (control), roots were evaluated at 3, 7, 10, 17, 24, 31, 38 and 45 days after inoculation for nematode development. At 45 days, M. javanica complete the life cycle in contrast to the low number of vermiform and swollen juveniles and no adult female of M. enterolobii found in roots. Using different nematode initial population densities, M. enterolobii did not affect initial sugarcane development at 120 days after inoculation. In contrast to M. javanica, M. enterolobii reproduction was inhibited presenting reproductive factor always lower than 1.