Effect of Storage Temperature and Duration on Survival and Infectivity of Steinernema innovationi (Rhabditida: Steinernematidae)

Tshimangadzo Ramakuwela, Justin Hatting, Mark D. Laing, Selcuk Hazir, Nicolene Thiebaut

Abstract


Entomopathogenic nematode species differ in their optimum storage temperature; therefore, we conducted a study on the survival and infectivity of the recently described Steinernema innovationi from South Africa at five storage temperatures (58C, 108C, 158C, 208C, and 258C) over 84 d using 20,000 infective juveniles (IJ) in 25 ml aqueous suspension containing 0.1% formalin. Our results showed that survival was highest and most stable at 158C, ranging from 84% to 88% after 84 d. Infectivity of IJ against Galleria mellonella larvae was .90% for all temperatures except for 58C at which survival decreased to 10% after 84 d. In addition, we stored 2.5 million IJ on a sponge formulation in 15 ml of 0.1% formalin solution for 84 d at the optimum 158C followed by 2 wk storage at 258C. Storage of the IJ on a sponge formulation for 14 d at 258C post 158C storage for 84 d did not have a detrimental effect on IJ survival (87%) or infectivity to G. mellonella (95%).

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