Water Congestion. In: Compendium of Pea Diseases and Pests

Authors: HAGEDORN, D - University Of Idaho; Porter, Lyndon

Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: 7/17/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Water congestion is an abiotic disorder resulting from excessive water present in intercellular spaces of plant tissue. In pea, water congestion is believed to result from lack of sufficient escape of water vapor from apical plant tissue under certain environmental conditions resulting in tissue damage expressed as water-soaked spots near the outer edges and on the underside of pea foliage. Water congestion is widespread in many pea-production areas. It is of concern due to leaf damage reducing the photosynthetic capacity of leaf surfaces, which may result in reduced growth and yield. First symptoms are very small, water-soaked spots near outer edges and on the undersides of pea foliage. These spots increase in size and number until the outer and terminal portions of leaves and stipules are completely water-soaked and appear darker green than healthy foliage. Gradual death of the affected tissue follows, progressing from the outermost tip and edge of the foliage toward the midvein. Water congestion is favored by adverse environmental conditions such as high humidity, warm temperatures, and high soil moisture. However, all three conditions need not be present for the disorder to occur. Other factors promoting water congestion include low potash content in soil and plant, high plant surface moisture and short photoperiods. Research has determined that plants homozygous for the allele for small stipule, st, are significantly less susceptible to the disorder. Water congestion can promote the development of bacterial and fungal diseases.

Technical Abstract: Water congestion is an abiotic disorder resulting from excessive water present in intercellular spaces of plant tissue. In pea, water congestion is believed to result from lack of sufficient escape of water vapor from apical plant tissue under certain environmental conditions resulting in tissue damage expressed as water-soaked spots near the outer edges and on the underside of pea foliage. Water congestion is widespread in many pea-production areas. It is of concern due to leaf damage reducing the photosynthetic capacity of leaf surfaces, which may result in reduced growth and yield. First symptoms are very small, water-soaked spots near outer edges and on the undersides of pea foliage. These spots increase in size and number until the outer and terminal portions of leaves and stipules are completely water-soaked and appear darker green than healthy foliage. Gradual death of the affected tissue follows, progressing from the outermost tip and edge of the foliage toward the midvein. Water congestion is favored by adverse environmental conditions such as high humidity, warm temperatures, and high soil moisture. However, all three conditions need not be present for the disorder to occur. Other factors promoting water congestion include low potash content in soil and plant, high plant surface moisture and short photoperiods. Research has determined that plants homozygous for the allele for small stipule, st, are significantly less susceptible to the disorder. Water congestion can promote the development of bacterial and fungal diseases.