Search Results
Altering the physical or chemical nature of the crop production environment through introduction of cover crops or other non-crop vegetation may amend the impact of various pests on vegetable crops. Current work is focused on the interaction of cereal cover crops and respective management systems with weed emergence and growth, white mold (Sclerotinia sclerotiorum) incidence, symphylan (Scutigerella immaculata) population dynamics, soil food-web structure, and crop yield in snap bean production systems. Research has demonstrated the potential of cover crop residues, tillage, and a single broadcast application of a postemergence herbicide to control summer annual weeds. Additionally, white mold incidence was significantly decreased by both reduced tillage conditions and flailed barley cover crop residues in one year of research. Two years of research indicate that symphylan density can be reduced by flailing spring-planted cereals before crop planting.
Five vineyard floor management treatments were evaluated for effects on weed control over two growing seasons in an establishing ‘Chardonnay’ (Vitis vinifera) vineyard in the Willamette Valley of Oregon. Four cover crop management treatments and an unplanted treatment were compared to assess the effects on vine row and alleyway weed coverage and densities of broadleaf and grass weeds. A winter annual cover crop was grown in alleyways of the cover-cropped treatments and was mowed in spring. The mowed residue was managed as follows: 1) residue transferred in-row as mulch representing the industry practice of “mow-and-throw,” 2) residue transferred in-row as mulch at three times the rate of the earlier treatment, 3) mowed residue incorporated into alleyways, and 4) removal of mowed cover crop residue from the vineyard. Weed coverage was assessed visually within a 1.0-m2 quadrat placed randomly in alleyways and vine rows, and densities of broadleaf and grass weeds were determined by counting and grouping individual weeds within each quadrat. Vine row weed coverage and densities were lower in treatments with residue mulch at each sampling date in 2009 and 2010, with nearly 100% in-row weed suppression by the heavier mulch treatment. Alleyway weed coverage was lowest when residue was incorporated and highest in the unplanted treatment at some sampling dates. Grass weed densities in alleyways were similar between treatments at all sampling dates. Results of this study indicate that in-row mulch of cover crop residues at fresh weight densities of 2.5–15.0 kg·m−2 provided effective weed control in a non-irrigated vineyard in western Oregon. Also, alleyway weed coverage may be reduced through incorporation of mowed cover crop residues.
Field studies were conducted in 1999 and 2001 in western Oregon to determine the effect of between-row spacing on severity of white mold (Sclerotinia sclerotiorum) in snap beans. Planting density was held constant at 445,000 plants ha–1 and between-row spacing ranged from 19 to 150 cm. Disease severity and pod rot were greatest in both years of study at the 19-cm between-row spacing and declined linearly as between-row widths increased. Severity of disease in 1999 was 24%, 41%, and 88% lower at the 38-, 75-, and 150-cm between-row spacings, respectively, than at the 19-cm row spacing. In 2001, disease severity was 11%, 25%, 34%, and 51% less at the between-row widths of 38, 75, 114, and 150 cm, respectively, than at the 19-cm row spacing. Incidence of pod rot declined by 0.24% and 0.64% for each 10-cm increase in between-row width in 1999 and 2001, respectively. The fungicide vinclozolin effectively suppressed pod rot in both years at all between-row spacings. Pod yield was not influenced by between-row spacings of 19 to 114 cm, but yield was significantly lower at the between-row spacings of 150 cm. Increasing the between-row width of snap bean rows may be an effective disease management tactic to suppress white mold when fungicides are not applied or if efficacious fungicides are not available.