Population fluctuation of Meloidogyne exigua in coffee plantation naturally infested by Pasteuria penetrans Flutuacao populacional de Meloidogyne exigua em cafezal naturalmente infestado por Pasteuria penetrans
Maximiniano, C.; Campos, V.P.ulo. de Souza, R.M.gela. de Almeida, A.R.sende.
Nematologia Brasileira. Junho; 251: 63-69
Populational fluctuation of Meloidogyne exigua associated to Pasteuria penetrans was studied in a 10-year-old coffee plantation area naturally infested with both organisms. Fifteen infested coffee trees were selected for the experiment. From the rhizosphere of these trees, 500 g of soil samples were collected monthly. Each sample was split into fine subsamples of 100 cm3 of soil and from them were extracted nematodes by Jenkins (1964) technique. The extracted second stage juveniles (J2) of M. exigua were observed with the use of an inverted objectives microscope and the number of J2 parasitized or not by P. penetrans was counted as well as the number of endospores/J2,. The percentage of J2 infested by P. penetrans varied from 21% to 65%. The number of endospores/J2 varied from 2.1 to 9.2 with, a tendency to increase in the spring. The population density of M. exigua J2 in the soil varied from 15 to 104 per 100 cm3 of soil, with a population increase in March and April. A positive correlation (r=0.58; P=0.0489) between the number of endospores/J2 and percentage of J2 infestation, air temperature and number of endospores/J2 (r=0.55; P=0.0626) was observed.