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United States Department of Agriculture

Agricultural Research Service

Title: Host Cadavers Protect Entomopathogenic Nematodes During Freezing

Authors
item Lewis, Edwin - VIRGINIA TECH
item Shapiro Ilan, David

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 22, 2002
Publication Date: February 1, 2003
Citation: LEWIS, E.E., SHAPIRO ILAN, D.I. HOST CADAVERS PROTECT ENTOMOPATHOGENIC NEMATODES DURING FREEZING. JOURNAL OF INVERTEBRATE PATHOLOGY. 2003. v.81. p.25-32.

Interpretive Summary: Insect-killing nematodes are small round worms that kill insect pests but do not harm people or the environment. We tested four different kinds (species) of these nematodes to see if they can withstand freezing temperatures when they are inside the insects they attack. We found that the nematodes can survive freezing and that being inside the cadaver may help them survive. Adult and third stage infective juvenile nematodes survive freezing better than other stages. This information helps us understand how these nematodes survive in nature, and could be used to develop ways to store the nematodes for commercial mass production.

Technical Abstract: Four species of insect-killing nematodes were exposed to freezing temperatures while inside their hosts. Survival was assessed by observing live and dead nematodes inside cadavers and by counting the infective juveniles (IJs) tht emerged after freezing. We 1) measured the effects of 24 hours of freezing at different times throughout the course of an infection, 2) determined the duration of freezing entomopathogenic nematodes could survive, 3) determined species differences in freezing survival. For S. carpocapsae and H. bacteriophora, the stages that survived were predominately IJs and adults. When cadavers were frozen two or three days after infection, few IJs emerged from them. Freezing between five and seven days after infection usually had no negative effect on IJ production. Heterorhabditis bacteriophora produced the most IJs after freezing. Heterorhabditis bacteriophora also showed improved survival inside versus outside their host when exposed to freezing.

Last Modified: 8/22/2014
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