Distribution and Diversity of Phytophthora species in Nursery Irrigation Reservoir Adopting Water Recycling System During Winter Months

Abstract

Irrigation water recycling is an increasingly important practice in agriculture in the context of diminishing water supply and the regulatory requirements in some parts of the world. This practice potentially accumulates and disseminates plant pathogens including Phytophthora species that pose a great threat to agriculture and forest ecosystems. Despite a high economic importance of Phytophthora species, the current understanding of their aquatic ecology is very limited. Therefore, a study was conducted to investigate the distribution and diversity of Phytophthora species in an irrigation reservoir of a commercial nursery in eastern Virginia over two consecutive winters. Multiple baits were deployed in surface water at a run-off entrance, 20, 40, 60 and 80 m from the entrance and near the pump inlet and at various depths at the 20-m station. Ten different Phytophthora species were detected in this study that included P. citrophthora, P. gonapodyides, P. hydropathica, P. inundata, P. irrigata, P. megasperma, P. pini, P. polonica, P. syringae and P. tropicalis. Phytophthora recovery declined through the winters from November to March. It also declined with distance from the run-off entrance. These results suggest that water decontamination during winter irrigation events is required at this nursery and possibly in the nurseries from the southern part of the United States. The placement of the pump inlet away from run-off entrance may be a viable strategy to reduce the crop health risk.

Recycling Irrigation Reservoir Stratification and Implications for Crop Health and Production

“…All suggest that thermal stratification is likely to affect the abundance and diversity of Phytophthora species in RIRs. This conclusion is well supported by the fact that we recovered high‐temperature tolerant P. hydropathica and P. irrigata much more frequently from the reservoir surface during warmer months, while P. gonapodyides and P. syringae were more abundant during cooler months (Ghimire et al ., ).…”

Phytophthora Species Recovered From Irrigation Reservoirs in Mississippi and Alabama Nurseries and Pathogenicity of Three New Species

“…The research generated lists of Phytophthora spp. recovered from symptomatic leaf, stem, crown, and root tissues; and from organic substrate, soil, and waterways in nursery production systems (Bush et al 2003;Ghimire et al 2009Ghimire et al , 2011Olson and Benson 2011;Olson et al 2013;Schwingle et al 2007;Warfield et al 2008;Yakabe et al 2009). Interestingly, species diversity varied with location, sampling source, and season.…”

Phytophthora hydropathica y Phytophthora drechsleri aisladas de canales de irrigación del Valle de Culiacán

“…Examples of species reported with this dispersal mean include P. cactorum, P. parasitica, P. citricola, P. gonapodyides, and P. cambivora, isolated from irrigation waters in the state of Washington (Yamak et al, 2002). Recently, one of the species with the greatest incidence in surface waters has been P. hydropathica (Brazee et al, 2016;Ghimire et al, 2011;Hulvey et al, 2010). In most of these cases,…”

“…Algunos ejemplos de especies reportadas con este medio de diseminación son: P. cactorum, P. parasitica, P. citricola, P. gonapodyides y P. cambivora, aisladas de aguas de irrigación en el estado de Washington (Yamak et al, 2002). Recientemente una de las especies con mayor incidencia en aguas superficiales es la especie P. hydropathica (Brazee et al, 2016;Ghimire et al, 2011;Hulvey et al, 2010). En la mayoría de estos casos, la presencia de especies de Phytophthora en agua no se ha relacionado con la existencia de síntomas o daños en hospedantes vegetales terrestres (Resser et al, 2011).…”