Pest Management Science (2010) 66, 696-704

Monday O. Ahonsi, Thomas J. Banko, Stargel R. Doane, Ayodeji O. Demuren, Warren E. Copes and Chuanxue Hong (2010)
Effects of hydrostatic pressure, agitation and CO₂ stress on Phytophthora nicotianae zoospore survival
Pest Management Science 66 (7), 696-704
Abstract: BACKGROUND: Phytophthora nicotianae Breda de Haan is a common pathogen of ornamental plants in recycled irrigation systems. In a previous study, annual vinca (Catharanthus roseus Don) inoculated with zoospore suspensions using a CO₂-pressurized sprayer had less foliage blight than plants inoculated using a hand sprayer. Here, the impact of hydrostatic pressure, agitation and aeration with CO₂ on the survival of P. nicotianae zoospores was examined.
RESULTS: Exposure of zoospores to 840 kPa hydrostatic pressure for 8 min or agitation at a mixing intensity (G) of 6483 s^-1 for 4 min at 22-23 °C did not kill zoospores, but resulted in viable cysts. Motile and forcefully encysted zoospores of P. nicotianae were equally infectious on vinca or lupine (Lupinus polyphylus Lindl.). Bubbling CO₂ into zoospore-infested water at 110.4 mL (0.2 g) min^-1 for 5 min caused 81% reduction in the number of germinated zoospores. Pressure at 630 kPa (16.3 g CO₂) or 70 kPa (3.85 g CO₂) facilitated CO₂ injection and shortened the zoospore inactivation time to 30 s. When air was bubbled through the suspension, germination was similar to the control.
CONCLUSIONS: Exposure to CO₂ killed P. nicotianae zoospores in water. Neither pressure nor agitation had an effect on zoospore viability or infectivity. Based on results of this study, the authors designed a recycling CO₂ water treatment system that is currently under evaluation.
(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): Monday O. Ahonsi, Warren E. Copes, Chuan-Xue Hong

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phytophthora nicotianae