Environmental and Management Factors Associated with Bacterial Diseases of Onion in Pennsylvania

Abstract

Bacterial diseases of onion may result in over 60% yield loss in crops grown in the Mid-Atlantic region, even when managed with recommended chemical and cultural practices. To identify environmental and production factors associated with the high incidence of bacterial rots in Pennsylvania, data on 32 environmental and management variables ranging from soil temperature to foliar nutrients were recorded during three visits to each of 28 and 26 fields, surveyed in 2011 and 2012, respectively. Multiple linear regression indicated negative relationships between foliar nitrogen and carbon at midseason and total incidence of bacterial rots. Soil temperatures near the physiological onset of bulbing were positively related to bacterial rots in multiple datasets. These results suggest greater complexity may be necessary for N fertility recommendations: timing of inorganic N application should be considered in addition to the seasonal N rate applied. Lower soil temperatures, particularly near the physiological onset of bulbing, may also reduce the incidence of bacterial rots of onion.

Reducing the risk of onion bacterial diseases: A review of cultural management strategies

“…Leaf tissue N concentration has been shown to have both positive and negative correlations with onion bacterial disease. The relationship depended on whether there was (A) excess N and, therefore, greater susceptibility to bacterial disease development, or (B) insufficient N and, therefore, stress that predisposed the plants to bacterial infection (Gitaitis et al., 2003a; Pfeufer & Gugino, 2018). The degree to which N application rates can be reduced to limit bacterial bulb rots without decreasing marketable yield depends on many factors.…”

“…Crop losses can vary depending on circumstances such as weather conditions, cultivar susceptibility, the specific bacterial pathogen(s) present, and inoculum sources. However, losses of more than 50% have been documented under the most disease‐conducive conditions (Pfeufer & Gugino, 2018; Schwartz & Mohan, 2008).…”

Nitrogen doses and sources applied as top-dressing in onion crops grown under no-tillage and conventional tillage systems

“…kurtz@epagri.sc.gov.br 3 Instituto de Assistência Técnica e Extensão Rural (EMATER), Lagoa Nova, RS, Brazil. rgoulartmachado@gmail.com *Corresponding author: leandrohahn@epagri.sc.gov.br Nitrogen (N) is the nutrient mostly absorbed by onion plants (Kurtz et al, 2016); however, it is the element mostly influencing crop yield, bulb quality (Kurtz et al, 2013) and disease incidence (Pfeufer & Gugino, 2018). Crops producing 37.34 t ha -1 of bulbs extract 101.4 kg ha -1 of N from the soil; 58.3 kg ha -1 (57%) of this total is exported through bulb harvesting (Kurtz et al, 2016).…”

Onion Yield and Internal Quality Increased by Straw Mulch and Reduced by Artificial Heat, but Not Affected by Kaolin Particle Film

“…alliicola, Enterobacter cloacae, and Pantoea agglomerans are the predominant bacterial pathogens causing internal decay of onion bulbs in Washington State (du Toit et al, 2016;Schroeder et al, 2009). Internal decay of onion caused by these thermophilic bacteria has been found to increase with increasing bulb curing temperature (Schroeder and du Toit, 2010;Schroeder et al, 2012;Vahling-Armstrong et al, 2015) and has been associated with excessive heat during bulb development (Bishop, 1990;Pfeufer and Gugino, 2018;Schwartz and Mohan, 2008). The fungus Fusarium proliferatum has also been found to cause bulb decay in Washington State (du Toit et al, 2003), and Fusarium basal rot can progress to bulb decay in storage (Schwartz and Mohan, 2008).…”