Effects of the nematode Phasmarhabditis hermaphrodita and of venom from the endoparasitic wasp Pimpla hypochondriaca on survival and food consumption of the pest slug Deroceras reticulatum; implications for novel biocontrol strategies.
BACKGROUND
Controlling pests through disruption of biochemical pathways by physiologically active compounds/factors from animals and plants represents an expanding field of research. The authors investigated whether such factors in venom from the wasp Pimpla hypochondriaca (Retzius) can affect the viability and food consumption of the slug Deroceras reticulatum (Müller), and whether they can improve the efficacy of nematode-induced slug mortality.


RESULTS
Exposure of slugs to 4 mL of water containing 500, 1000 and 5000 Phasmarhabditis hermaphrodita (Schneider) resulted in significant increases in mortality (with hazard ratios of 3.5, 3.9 and 5.8 respectively) and significant reductions in total food consumption and mean food consumption each day for 21 days. Injection of slugs with 4, 8 or 12 microL of P. hypochondriaca venom resulted in significant increases in mortality (with hazard ratios of 3.3, 4.5 and 9.0 respectively) and significant reductions in total food consumption compared with the controls. However, there was no significant effect of venom on the mean food consumption on individual days of the 21 day assay period, although significant reductions occurred for the 8 and 12 microL doses up to day 10. Injecting slugs with 4 microL of venom prior to exposure to 500 nematodes had no synergistic effect on either mortality or food consumption compared with either of the individual treatments.


CONCLUSIONS
Pimpla hypochondriaca venom contains factors capable of killing and reducing food consumption by D. reticulatum. The utilization of these factors as components of integrated pest management strategies is discussed.
Richards
Elaine H
EH
Central Science Laboratory, Sand Hutton, York, Y041 1LZ, UK. e.richards@csl.gov.uk
DeMarzo
Damian
D
Port
Gordon R
GR
Dani
M Paulina
MP
Walters
Keith F A
KF
D000818:Animals; D018556:Crops, Agricultural / Q000191:economics; D004435:Eating; D049851:Gastropoda / Q000166:cytology / Q000187:drug effects / Q000469:parasitology* / Q000502:physiology*; D010572:Pest Control, Biological; D017172:Rhabditoidea / Q000187:drug effects / Q000502:physiology*; D013534:Survival; D014862:Wasp Venoms / Q000494:pharmacology*; D014863:Wasps / Q000378:metabolism*
D014862:Wasp Venoms