Effect of application method on fitness of entomopathogenic nematodes emerging at different times.

The entomopathogenic nematode species Steinernema feltiae and Heterorhabditis bacteriophora were compared for survival and infectivity of infective juveniles (IJ) collected with a standard White trap (i.e., emerging from hosts and accumulating in water) and later applied to sand (treatment A) to IJ allowed to emerge from hosts into sand (treatment C). Percentage IJ survival and infectivity was compared between treatments for S. feltiae IJ that emerged between days 1 to 3 and days 4 to 6. For H. bacteriophora, percentage IJ survival and infectivity was compared between treatments only for infective juveniles that emerged between days 4 to 6. For S. feltiae IJ percentage survival and infectivity decreased with time (P </= 0.05) and was greater (P </= 0.05) for IJ from treatment C than for IJ from treatment A. For H. bacteriophora IJ percentage survival decreased (P </= 0.05) and percentage infectivity increased (P </= 0.05) with time. While percent survival was higher (P </= 0.05) for treatment C than for A, percent infectivity was not different between treatments.