BioControl (2009) 54, 307-321

Rodrigo Diaz, William A. Overholt, James P. Cuda, Paul D. Pratt and Alison Fox (2009)
Host specificity of Ischnodemus variegatus , an herbivore of West Indian marsh grass (Hymenachne amplexicaulis)
BioControl 54 (2), 307-321
Abstract: West Indian marsh grass, Hymenachne amplexicaulis Rudge (Nees) (Poaceae), is an emergent wetland plant that is native to South and Central America as well as portions of the Caribbean, but is considered invasive in Florida USA. The neotropical bug, Ischnodemus variegatus (Signoret) (Hemiptera: Lygaeoidea: Blissidae) was observed feeding on H. amplexicaulis in Florida in 2000. To assess whether this insect could be considered as a specialist biological control agent or potential threat to native and cultivated grasses, the host specificity of I. variegatus was studied under laboratory and field conditions. Developmental host range was examined on 57 plant species across seven plant families. Complete development was obtained on H. amplexicaulis (23.4% survivorship), Paspalum repens (0.4%), Panicum anceps (2.2%) and Thalia geniculata (0.3%). Adults survived 1.6 times longer and laid 6.6 times more eggs on H. amplexicaulis than the other species. Oviposition on suboptimal host species was positively related to I. variegatus density under multiple choice conditions. Results from field experiments indicated that H. amplexicaulis had higher densities of I. variegatus than other species. Spill-over to suboptimal hosts occurred in an area where H. amplexicaulis was growing in poor conditions and there was a high density of I. variegatus. Thus, laboratory and field studies demonstrate that I. variegatus had higher performance on H. amplexicaulis compared to any other host, and that suboptimal hosts could be colonized temporarily.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Rodrigo Diaz, William A. Overholt, James P. Cuda, Paul D. Pratt

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
non-target effects/fate in environm.
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Hymenachne amplexicaulis (weed)		U.S.A. (SE)
Ischnodemus variegatus (weed bioagent)	Hymenachne amplexicaulis (weed)		U.S.A. (SE)