Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2012
Publication Date: 5/2/2012
Citation: Li, S., Jin, X., Chen, J. 2012. Effects of piperidine and piperideine alkaloids from the venom of red imported fire ants, Solenopsis invicta Buren, on Pythium ultimum Trow growth in vitro and the application of piperideine alkaloids to control cucumber damping-off in the greenhouse. Pest Management Science. 68:1546-1552. doi: 10.1002/ps.3337. Interpretive Summary: This is the first report that describes our findings of using purified alkaloids, piperidine and piperideine extracted from the venom of red imported fire ant against the growth of a destructive plant pathogenic fungus, Pythium ultimum in laboratory and in the greenhouse. Both alkaloids effectively inhibited the linear growth of P. ultimum on potato dextrose agar plates. The piperidine alkaloids were stable after 12 week storage in refrigerator (4oC) or at room temperature (22oC). When stored at 54oC, the inhibitory activity was stable for 4 weeks, and then started to decline. Higher concentrations of piperidine resulted in better inhibitory effects in reducing mycelium growth and sporangia (spores) germination. Drench treatment significantly improved the seedling emergence and seedling height of cucumber in greenhouse. Our discovery may lead to the development of new types of safer fungicides.
Technical Abstract: Pythium ultimum Trow is a plant pathogen that causes significant yield losses on many economically important crops. Chemical seed treatment has been used for disease control. In searching for alternatives, the venom alkaloids from red imported fire ant were tested against P. ultimum in vitro and to control cucumber damping-off in the greenhouse. Piperidine and piperideine alkaloids of the red imported fire ant significantly inhibited the mycelial growth of P. ultimum. Piperidine alkaloids were stable at both room and elevated temperatures. The inhibitory activity positively corresponded to the concentrations of piperidine alkaloids in the medium, and the EC50 = 17.00 µg mL-1. Germination of sporangia of P. ultimum negatively corresponded to the concentrations of piperidine alkaloids in the medium, and the EC50 = 12.25 µg mL-1. Drenching treatment significantly improved the seedling emergence and seedling height of cucumber in greenhouse. This is the first report using piperidine and piperideine alkaloids from the red imported fire ant to control damping-off disease caused by P. ultimum. These findings may lead to the development of a new group of fungicides.