Author
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Gouge, Dawn |
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Henneberry, Thomas |
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Lee, Linda |
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Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 8/1/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The entomopathogenic nematode species Steinememafeltiae, S. riobravis, and Heterorhabditis bacteriophora were all found to parasitize nymphs of Bemisia argentifolii (SLW). The infective juvenile nematodes were sprayed onto cotton leaf surfaces infested with SLW nymphs. Leaves were contained within humidity chambers to increase nematode survival. The infective juveniles of the steinemematid species appear to be entering beneath the operculum through the vasiform orifice of second and third instar nymphs. Heterorhabditid nematodes are capable of entering insect bodies directly through intersegmental membranes, so either method of entry may be employed by H. bacteriophora. No more than three nematodes were ever seen infecting a single insect and subsequent development of the nematodes within was very rapid. Adults of S. feltiae, and S. riobravis were recorded after 24 hours of nematode application. The adult females of S. riobravis and S. feltiae were stunted in growth. The "pygmy" forms did produce viabl offspring. Death of the nymph was indicated by development of a red body color. It appears that red eye pigment becomes disseminated through cadaver as septicemia of body tissues occurs. Adult SLW were also occasionally infected by nematodes, but the avenue of infection is unclear. Unfortunately although SLW can be parasitized by the species of nematodes tested, infection levels never exceeded 20% of nymphs contained on a leaf. |
