LIFE STAGES IDENTIFICATION AND EMBRYOLOGY OF THE VIRUS-VECTOR NEMATODE XIPHINEMA INDEX

Abstract

Xiphinema index life stages are illustrated and differentiated on the basis of body length and, functional and replacement odontostyle. The length of the replacement odontostylet on one stage corresponds to the length of functional odontostylet of the previous stage. Odontostyle length increased from 49±4.6 (38-55) µm for the first stage juveniles to 135±2.8 (128-138) µm for the female and male with a growth rate of 61%,35%,30% and 13% compared to the previous stage for J2' J3' J4 and adults respectively. X. index completes embryogenic development in 10-12 days at 24±2ºc. The embryogenic development starts shortly after egg laying and the 2- and 4-cell stages are reached after 220/0 of the total embryogenic development time. Thereafter divisions are more rapid, with gastrulation and juvenile after about half (57%) of the total developmental rime. The juvenile moves actively during elongation (s-stage phase) which is followed by 2-3 days quiescence. Shortly before hatching, activity is resumed and is accompanied by an evident flexibility of the egg membrane.