Effect of Sprinkler Irrigation on Bacterial Soft Rot and Yield of Broccoli

Abstract

The effect of amount of applied water under two irrigation frequencies (once versus three times per week) on the incidence of bacterial soft rot, caused by Erwinia carotovora subsp. carotovora, and yield of broccoli was investigated in field studies conducted in 1987 and 1988. At head initiation, the amount of applied water was varied by utilizing a line source irrigation system. Incidence of soft rot was higher in the OSU breeding line 86-3 plots, followed by cv. Citation and then cv. Gem. Soft rot was not consistently affected by amount of applied water. Differences in amount of disease were apparent, however, between the separate irrigation frequency studies in 1988; disease incidence more than doubled under the high- compared with the low-frequency irrigation. Further studies on the effects of frequency and timing of sprinkler irrigation on soft rot and yield of Gem broccoli were undertaken in 1993 and 1994. Six sprinkler irrigation regimes, a factorial combination of frequency (irrigation every 2, 4, or 8 days) and timing (morning or evening), were established. Total water applied did not differ by treatment. Incidence of soft rot was negligible at the first harvest in both years. At the last harvest, the incidence of soft rot was significantly reduced, from 22 to 10% in 1993 and from 30 to 15% in 1994, by the change in frequency of irrigation from 2 to 8 days. In contrast, timing of irrigation had no effect on disease incidence. Yield of broccoli was not affected by either frequency or timing of irrigation.

Pectobacterium carotovorum subsp. carotovorum - the causal agent of broccoli soft rot in Serbia

“…The disease affects both floret and stem tissue. It appears first as a water-soaked lesion followed by maceration and soft rotting of tissue (Ludy et al, 1997). Campbell et al (1995) reported that soft rot of broccoli, caused by two genera of bacteria, Pectobacterium and Pseudomonas, had led to crop losses of between 30% and 100%, costing the UK industry £9.5 million annually (as cited in Darling et al 2000).…”

Evidence that DL‐3‐aminobutyric acid and acibenzolar‐S‐methyl induce resistance against bacterial head rot disease of broccoli

“…Erwinia carotovora as a causal agent of the disease is controversial. In fact, Ludy and Powelson18 were unable to obtain infection with Pseudomonas , but successfully got infection with E. carotovora in field inoculations in Oregon (USA). Canaday et al 6 in the USA have also obtained infection with P. marginalis and E. carotovora, while Wimalajeewa et al 4, 19 and Hildebrand5 were not able to reproduce head rot symptoms with E. carotovora but were successful with isolates of P. fluorescens biovar IV and P. marginalis .…”

Oxygen-Dependent Globin Coupled Sensor Signaling Modulates Motility and Virulence of the Plant Pathogen Pectobacterium carotovorum

“…In terms of environmental signals, oxygen (O 2 ) concentration has been demonstrated to affect the pathogenicity of soft rot bacteria, but the mechanism by which O 2 is sensed and the signal transmitted within Pectobacterium has yet to be established. Decreased O 2 levels, relative to air, are often found when fields are flooded or crops are stored without adequate ventilation , and lead to increased rotting. This is likely in part because the plant wound response requires O 2 for generation of reactive oxygen species to cross-link proteins and sugars within their cell walls to isolate the infection, as well as kill the invading microbes. − Therefore, at low O 2 levels, the plants are unable to adequately repel microbial invasions.…”