LIFE STAGES IDENTIFICATION AND FEEDING BEHAVIOR OF OGMA CIVELLAE

Abstract

Ogma civellae life stages are illustrated and differentiated on the basis of ovary development, body length, stylet length, cuticular ornamentation and arrangement of scales. Second-stage juveniles have body annules without spines, and body, ovary and stylet 138-177, 8-10, and 34-39 µm long, respectively. The third-stage juveniles have body annules with 4-6 palmate and spinate scales, ending with a variable number and form of projections disposed in eight longitudinal rows. This stage has body, ovary, and stylet 203-263, 16-19, and 45-60 µm long, respectively. The fourth-stage juveniles each have body annules with 8 scales similar to those of J3, disposed in 8 longitudinal rows and body, ovary, and stylet 368-385, 60-85, and 62-69 µm long, respectively. Adult females maturity can be distinguished by body, ovary and stylet lenght of 381-531, 282-382, and 70-84 µm, respectively, and their unique cuticular ornamentation. Each of the anterior 60-63 body annules bears a continuous fringe with 66-80 spines showing simple or bifurcated tips, while 8-10 terminal annules bear palmate projections in alternate rows. Histological examination of Ipomoea batatas roots infected by O. civellae indicated that the nematode feeds ectoparasitically on the epidermal and hypodermal cells. Feeding tubes surrounding the stylet were observed in these cells.