Biology of Seinura paratenuicaudata Geraert

R. Vats, R. S. Kanwar, H. K. Bajaj

Abstract


The life cycle and feeding of 5einura paratenuicaudata was studied on 1 % water agar in vitro using Aphelenchus avenae as prey. 5einura paratenuicaudata reproduces uniparentally. Eggs are laid only after it has fed upon its prey. The first moult occurs inside the egg and the second stage juvenile hatches out. Oesophageal gland secretions and mechanical pressure, exerted by both ends but not the stylet of the developing J2 , are involved in rupturing the eggshell. The secretion of dorsal oesophageal glands is also involved in exsheathment during further moulting. The life cycle is completed in 4-5 days. For feeding, the predator inserts its stylet into the prey body and this is followed by injection of the contents of the dorsal oesophageal glands, which paralyse the prey. The body contents of A. avenae are subsequently sucked out by the predator. Studies on host preference of 5. paratenuicaudata revealed that it feeds and reproduces on Aphelenchoides bicaudatus, A. composticola, Aphelenchus avenae, A. radicicolus, Ditylenchus myceliophagus and second stage juveniles of Heterodera cajam; Meloidogyne incognita and M. javanica, but not on larval stages or adults of Helicotylenchus dihystera, Hop 10 la im us in dicus, Longidorus pisi, second stage juveniles of Heterodera avenae, H. sorghi or H. zeae, or males of M. incognita or M. javanica. It feeds and reproduces on J2 of Anguina tritici and J3 of 5ubanguina chrysopogoni but the majority of the eggs produced are unfertile. Temperature also influences the feeding and reproduction of this predator. The optimum temperature for reproduction is between 20 and 35 DC. The nematode fails to feed or multiply at 11 and 15 DC but remains active.

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