Limited storage stability severely restricts the biological control potential of slug-parasitic nematodes. In a series of experiments, we evaluated the effects of temperature and osmotic desiccation on the short- and long-term survival of the slug-parasitic nematode Phasmarhabditis hermaphrodita. Nematode survival in petri dishes at 1,500 infective juveniles/ml did not differ significantly at 5, 10, and 15 C but declined rapidly at 25 and 30 C. At 25 C about 50% of the nematodes survived for 4 wk, but at 30 C no nematode survived past 1 day. About 50% of the nematodes survived for 32 wk at 20 C. About 35–40% of the nematodes survived up to a year at 5, 10, and 15 C. Phasmarhabditis hermaphrodita showed poor survival under osmotic desiccation in glycerol with 15 and 20% glycerol significantly reducing survival at 5 and 15 C. Although the nematodes tolerated 10% glycerol, this level of desiccation also did not enhance long-term survival at either 5 or 15 C. There was a significant decrease in nematode survival in 10% glycerol at 25 C during the first 2–3 wk, but about 16% of the nematodes survived for 6 wk in 10% glycerol as compared with only 1% survival in water. The greatest benefit of osmotic desiccation in glycerol was observed in the enhanced survival of P. hermaphrodita at temperature extremes. Over 96% of the nematodes survived a 6-hr exposure to 35 C in 10% glycerol, whereas only 9% survived in water. Similarly, over 90% of the nematodes survived an exposure to −20 C for 4 hr in 10% glycerol, but less then 2% survived in water. We conclude that 5–15 C is an optimum temperature range for the storage of P. hermaphrodita. We also conclude that osmotic desiccation in 10% glycerol can substantially increase survival of P. hermaphrodita at temperature extremes (35 and −20 C) for short periods but has no effect on nematode longevity at the optimum temperature range of 5–15 C.
EFFECT OF OSMOTIC DESICCATION ON LONGEVITY AND TEMPERATURE TOLERANCE OF PHASMARHABDITIS HERMAPHRODITA (NEMATODA: RHABDITIDAE)
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Sukhbir K. Grewal, Parwinder S. Grewal; EFFECT OF OSMOTIC DESICCATION ON LONGEVITY AND TEMPERATURE TOLERANCE OF PHASMARHABDITIS HERMAPHRODITA (NEMATODA: RHABDITIDAE). J Parasitol 1 June 2003; 89 (3): 434–438. doi: https://doi.org/10.1645/0022-3395(2003)089[0434:EOODOL]2.0.CO;2
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