Raised Beds and Metalaxyl for Controlling Phytophthora Root Rot of Raspberry

Abstract

<jats:p>`Titan' red raspberry <jats:italic>(Rubis idaeus</jats:italic> L.), highly susceptible to root rot caused by <jats:italic>Phytophthora fragariae</jats:italic> Hickman var. <jats:italic>rubi</jats:italic> Wilcox <jats:italic>&amp;</jats:italic> Duncan (syns. <jats:italic>P. erythroseptica</jats:italic> Pethyb., “highly pathogenic” <jats:italic>P. megasperma</jats:italic> Drechs.), was planted in June 1990 in a silt loam naturally infested with the pathogen. Raked beds (0.36 m high) dramatically reduced disease incidence and severity relative to flatbed treatments. In contrast, metalaxyl at 372 mg·m<jats:sup>-1</jats:sup> of row provided little benefit when applied to flat beds and provided consistently moderate but statistically insignificant effects when applied to raised beds. Relative to the flat bed system, primocane vigor was increased in 1992 by 16%, 190%, and 224% in the flat bed plus metalaxyl, raised bed, and raised bed plus metalaxyl treatments, respectively; total yields were increased by 7%, 231%, and 272% with these same respective treatment. The results indicate that raised-bed planting systems can provide substantial control of phytophthora root rot of red raspberries even when highly susceptible varieties are grown on otherwise marginal sites. Metalaxyl appears more effective as a supplement rather than substitute for raised beds under such conditions. Chemical name used: <jats:italic>N-</jats:italic> (2,6-dimethylphenyl) <jats:italic>-N-</jats:italic> (methoxyacetyl)alanine methyl ester (metalaxyl).</jats:p>

Inheritance of Phytophthora root rot resistance in red raspberry determined by generation means and molecular linkage analysis

“…rubi Wilcox and Duncan, reduces crop productivity and is a major production constraint in all raspberrygrowing regions of the world (Wilcox et al 1993;Wilcox and Latorre 2002). An integrative management approach utilizing resistant cultivars, registered fungicides, and avoidance or amelioration of wet soils to reduce the eVects of the disease is recommended for control (Wilcox et al 1999;Heiberg 1995;Maloney et al 1993). Typical symptoms include severe root rot, leaf chlorosis, stem and petiole lesions and necrosis, and wilting (Wilcox 1989).…”

Pathogenicity, Fungicide Resistance, and Genetic Variability ofPhytophthora rubiIsolates from Raspberry (Rubus idaeus) in the Western United States

“…An integrative management approach, including development of resistant raspberry cultivars, fungicides and fumigants, and avoidance of wet soils, is suggested for control of this disease (12,20,38). A clear understanding of the species involved is essential for the management of Phytophthora root rot.…”

Suppression of Phytophthora Root Rot in Red Raspberries with Cultural Practices and Soil Amendments

“…Selection and modifi cation of planting sites to provide rapid drainage of water away from the base of peach trees assisted in phytophthora disease control (Wilcox and Ellis, 1989). Similarly, the use of raised beds in raspberry production has reduced PRR development in several fi eld trials (Heiberg, 1995;Maloney et al, 1993;Wilcox et al, 1999b).…”

“…rubi (Bristow and Windom, 1992). Metalaxyl has been benefi cial when used as a component of an integrated management system including raised beds and/or genetic host resistance (Maloney et al, 1993;Wilcox et al, 1999b). Various forms of phosphorous acid also have been used in the management of different phytophthora diseases (Bristow and Windom, 1992;Lim et al, 1990;Pegg et al, 1990;Wicks and Hall, 1990).…”