Corn

For the past several years a "stalk rot" disease has been afflicting commercial sweet corn fields grown in the Willamette Valley. The disease seems to have a pathogenic basis, but the exact causal agent is unknown.
Eighteen hybrids with se or su endosperm were evaluated for resistance to root/crown rot. Ears were also evaluated for processing quality.

Objectives: Characterize su and se sweet corn hybrids for reaction to root/crown rot.

Cooperator: M. Powelson, Botany and Plant Pathology

The cause of sweet corn root rot has been difficult to determine. Extensive sampling and surveying indicate the fungal pathogens Pythium arrhenomanes and Fusarium oxysporum and solani are consistantly associated with diseased roots.

Experiments were conducted during 1999 to determine: 1) if the cause of root rot of sweet corn is biotic, 2) if the disease is associated with plant nutrition, and 3) the potential role of stress in disease development and 4) the effect of soil treatments on reducing severity of root rot symptoms.

COOPERATOR:

 This project focuses on developing and evaluating strip-tillage vegetable production systems which integrate winter-annual cover crops. Goals include increasing farm income and enhancing soil and water quality. A new strip-till machine using chisel plows and rolling fluted coulters was tested in seven on-farm, paired comparisons with conventional "grower practice" tillage for sweet corn production.

Grower Participants:

Report to the Oregon Processed Vegetable Commission

Philip Hamm George Clough, and Mike Baune
OSU Hermiston Agricultrual Research and Extension Center

Lindsey du Toit and Lois Carris
Washington State University

Objectives:

PROJECT OBJECTIVES

Several root-invading plant pathogens have been found in symptomatic sweet corn roots, Fusarium oxysporum, F. solani, and Pythium species, but their involvement in the symptoms observed in the field was still unclear (Powelson et al., unpub.) in the spring of 2000.

Objectives:

While Fusarium oxysporum and solani and Pythium arrenhomanes are consistantly associated with diseased roots and Pythium arrhenomanes has been shown to be pathogenic on sweet corn seedings in the greenhouse, other studies suggest neither fungus alone is the cause of this disease. Experiments were conducted in 2000 to determine: 1) pathogenicity of Fusarium isolates and other fungi on sweet corn seedlings, 2) effect of soil treatments (fungicides and herbicides) on severity of root necrosis of corn grown in naturally infested field soil, and 3) effect of c

Objectives for 2000:

• To evaluate the N uptake efficiency of sweet corn varieties.
• To evaluate the effects of several fall-seeded and overseeded (relay interplanted) triticale, fall-seeded triticale plus common vetch, and overseeded red clover, on yield of sweet corn fertilized at three rates of N. The cover crops follow snap beans with three rates of N.
• To evaluate the effect of the cover crops and the N applied to the sweet corn on the amount of nitrate leached below the root zone.

Objectives:

• Characterize su sweet corn hybrids for reaction to root/crown rot.

Cooperators:

• M. Powelson, Botany and Plant Pathology, Oregon State University
• C. Ocamb, Botany and Plant Pathology, Oregon State University

Report to the Oregon Processed Vegetable Commission

George Clough, Philip Hamm, and Mike Baune
OSU Hermiston Agricultrual Research and Extension Center

Lindsey du Toit
WSU Mt. Vernon Research and Extension Unit

Objectives: