Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2019
Publication Date: 1/3/2020
Citation: Farrar, R.R., Gundersen, D.E., Kuhar, D.J., Blackburn, M.B. 2020. Insecticidal activity of Chromobacterium phragmitis, a recently described bacterium from tidal marshes. Journal of Entomological Science. 55(1):98-104.
Interpretive Summary: Increasing demand for organic produce leads to increasing use of a limited number of organic insecticides, increasing the chances that pests will develop resistance to them. To address this problem, a new species of insecticidal bacteria, Chromobacterium phragmitis was discovered in freshwater tidal marshes along the Potomac and James Rivers in the Chesapeake Bay watershed. The new bacterium produces natural products that are toxic to larvae of beetles, moths and flies. The new species will be of interest to organic growers, companies that produce natural insecticides for the organic market, and scientists prospecting for new species of bacteria for use in biological insect control.
Technical Abstract: Several isolates of the recently described bacterial species Chromobacterium phragmitis Blackburn et al. were obtained from water collected from low salinity tidal marshes in Maryland and Virginia, USA. Bacteria were cultured in a liquid medium and applied to artificial diets in the laboratory. One of two Maryland isolates, IIBBL 113-1, was highly toxic to larvae of the cabbage looper, Trichoplusia ni (Hübner) and the diamondback moth, Plutella xylostella (L.). The other Maryland isolate, IIBBL 112-1, and the Virginia isolates, were less toxic to these species. Maryland isolates were toxic to larvae of the seedcorn maggot, Delia platura (Meigen), while a Virginia isolate, IIBBL 274-1, was of intermediate toxicity against D. platura. The C. phragmitis isolate IIBBL 113-1 was toxic to adults of the red flour beetle, Tribolium castaneum (Herbst), while other C. phragmitis isolates had no activity against this species.