Penicillium mould of barley

Penicillium hordei is a fungal species known to cause significant degradation in barley and other cereal crops. This pathogen is a type of storage mould that predominantly affects seeds and grains, thriving particularly well when post-harvest conditions are not adequately managed, leading to severe economic losses for farmers and grain storage facilities.

The host range for this pathogen primarily includes barley, but it can also infect wheat, oats, and various other grains if the conditions are favourable. The infection can begin in the field during wet harvest conditions, but the most aggressive development typically occurs once the grain has been placed into storage, especially if moisture levels are poorly controlled.

Symptoms of the infection include the appearance of a characteristic blue-green or grey-green powdery mould on the grain surface. As the infection progresses, the grain embryo may become discoloured or necrotic, leading to a significant loss of germination vigor. The presence of the fungus often leaves a distinct musty or earthy odour, which is a key indicator of grain deterioration.

The development of Penicillium hordei is strictly linked to moisture and temperature. It proliferates rapidly in grain with a moisture content above 14–15% and temperatures ranging from 15°C to 25°C. Poor ventilation in silos and storage units allows the fungus to spread quickly from initial localized infection points to the entire grain pile.

• Ensuring grain is thoroughly dried to safe storage moisture levels immediately after harvest.
• Maintaining proper aeration and cool temperature levels within storage facilities.
• Applying systemic fungicides as seed treatments before the sowing season begins.
• Implementing strict sanitation protocols for grain storage equipment and warehouses.
• Cleaning grain thoroughly to remove dust, chaff, and damaged seeds that harbor fungal spores.

The damage caused by this pathogen is multifaceted, ranging from reduced seed viability to complete quality loss. Furthermore, many species of Penicillium are capable of producing mycotoxins, which poses a serious risk to food safety and livestock health if the contaminated grain enters the feed or food supply chain.