BIOLOGY OF COLUMBIA LANCE NEMATODE ( HOPLOLAIMUS COLUMBUS SHER) ON SOYBEAN EXCISED ROOT CULTURE

Abstract

Feeding, egg development and oviposition, embryology, and postembryonic development of Hoplolaimus columbus were observed on soybean (cultivar Hutcheson) excised root culture in Gamborg[sub2]s B5 medium (pH 5.7, 1.3% agar). Petri plate sterile cultures were placed inverted on a heated microscope stage (30 x C) and observations were conducted using a color video camera and a time lapse digital videocassette recorder. Oöcytes were observed in each gonad 38 hours after feeding commenced and an egg possessing a terminal stalk was laid 96 hours later. Eggs were deposited in the one-celled stage and a total of 217 hours (9 days) was required for a newly laid egg to develop into a hatching second-stage juvenile at 30 x C. Postembryonic development consisted of three juvenile stages and an adult female with prior feeding occurring before molts and oviposition. The nematode fedectoparasitically on the subepidermal cells and endoparasitically in the cortex and outer vascular tissue and remained at the infection site for 2-9 days.