Pink seed

Pink seed is a bacterial disease caused by the plant pathogen Erwinia rhapontici. This bacterium is distinct for its ability to produce a pink or salmon-colored pigment that accumulates on the surface of infected seeds and plant tissues, making the disease visually recognizable at harvest.

The disease primarily impacts pulse crops, specifically chickpeas, and is also known to cause significant issues in winter wheat. While it may infect other plants like bulbs or flowers, its economic impact is most critical in cereal and legume production due to direct damage to the harvested grain quality.

Symptoms typically manifest as a pink to reddish discoloration of the seed coat. In infected wheat, this results in "pink grain," which is often downgraded in quality and unsuitable for flour milling. For chickpeas, the infection leads to reduced seed viability and can cause lesions on the pods during the growing season.

The development and spread of Erwinia rhapontici are heavily favored by humid weather conditions, particularly during the seed-filling and maturation stages. The bacteria can persist in crop residues, soil, and on the surface of infected seeds, which serves as the primary pathway for seasonal transmission.

Control measures are primarily preventive, as there are no effective curative treatments for the infection once it has taken hold in the field. Effective management strategies include:

• Utilizing disease-free, certified seed stocks.
• Implementing long-term crop rotation to reduce pathogen load in the soil.
• Removing volunteer plants and weeds that may act as alternative hosts.
• Treating seeds with appropriate disinfectants prior to planting to minimize early-stage infection.