Monilia blight

Monilia blight, caused by the fungus Monilinia laxa, is a devastating disease affecting stone fruit orchards worldwide. While sometimes referenced in older or erroneous taxonomic records under outdated names, this pathogen is widely recognized in modern agronomy as the primary cause of blossom and twig blight in fruit trees.

The disease primarily targets stone fruit species, including apricots, cherries, peaches, and plums. It is particularly destructive during the early spring bloom, as the infection enters the tree through the flowers and subsequently spreads into the fruit-bearing spurs and branches.

The classic symptom of the disease is a sudden collapse and browning of blossoms, which then leads to the wilting of entire twigs and small branches. The affected areas appear scorched, resembling the damage caused by fire. Eventually, grayish spore-bearing tufts may emerge from the infected bark surfaces under humid conditions.

The development of the fungus is strictly dependent on climatic factors. Extended periods of cool, wet weather during the flowering stage provide ideal conditions for spore germination and infection. High humidity and spring rains are the most significant drivers of disease spread within and between orchards.

In terms of economic impact, Monilia blight can cause catastrophic yield losses and structural damage to the trees, leading to long-term decline in vigor. Mitigation strategies are essential and include rigorous pruning of infected wood, the removal of mummified fruit, and the strategic application of fungicides to protect open blossoms.

• Pruning and destroying infected twigs during the dormant season.
• Removing all mummified fruits from trees and the ground.
• Applying preventive fungicides at the pink bud stage.
• Maintaining proper orchard spacing to encourage airflow.