Infectivity of Nictating Juveniles of Steinernema carpocapsae (Rhabditida: Steinernematidae)

Abstract

The rates of nictating Steinernema carpocapsae infective juveniles (IJs) were mostly 20 and 10% for nematodes harvested from Galleria mellonella, and for those from chicken offal medium, resp. Repeated use of nictating IJs for the nictation performance did not raise the rate, but kept almost to the initial levels. After 4 performances, the number of nictating individuals became 0.16% of the initial population. The nictating IJs were more attracted to the host (larval plasma of Spodoptera litura) and more entered the host insect than non-nictating IJs obtained from nematode-water suspension. There were no significant differences in the migration/penetration between the nictating IJs with and without insecticides; acephate, permethrin and oxamyl at 50 µg/ml each. The experiments confirmed that nictating behaviour was a positive or precursory behaviour for infection of S. carpocapsae