Measles
Phaeoacremonium spp.
What is Measles (Phaeoacremonium spp.)?
Measles is a group of fungal diseases that affect grapevines. It is caused by different fungi, including Phaeoacremonium aleophilum, and Phaeomoniella chlamydospora. Symptoms include striped patterns on leaves, dark spots on wood in circular patterns, and necrotic spots on berries. The appearance of foliar and fruit symptoms can change each year due to variations in toxin production caused by climate. In severe cases, it can lead to sudden shoot dieback, also known as "apoplexy."
How does Measles (Phaeoacremonium spp.) occur?
Measles affects vineyards after 5 to 7 years of planting, but it infects younger vines. Spores are produced in diseased wood during winter and are released when it rains in fall and spring. Pruning wounds provide entry points for infection. Wounds are vulnerable for a few weeks, but their susceptibility reduces over time. Once infected, the pathogen causes a permanent wood infection that cannot be eliminated with fungicides. Spores spread through wind or rain, leading to the disease's spread within vineyards.
Symptoms
1 - Impact on Plants
Measles cause significant damage to grapevines, leading to leaf striping, necrotic spots, premature leaf drop, fruit darkening, cracking, and spoilage. Shoot dieback reduces photosynthesis and yield, resulting in economic losses and vineyard replanting needs.
2 - Soil Health
Measles has impacts on the soil. Fungal colonization associated with the disease can impair root function, leading to reduced nutrient uptake. Additionally, weakened vines are more vulnerable to other soil-borne pathogens, increasing the risk of additional diseases.
Solutions
1 - Prevention
• Opt for grapevine cultivars that exhibit resistance to Measles, reducing the susceptibility of the plants to the disease. • Regularly remove and dispose of infected wood and pruning debris to minimize the presence of inoculum and prevent disease spread. • Apply sealants on pruning cuts to create a barrier and prevent fungal infections from entering the plant. • Implement practices that optimize airflow within the vine canopy and reduce humidity levels, creating less favorable conditions for disease development. • Ensure proper irrigation practices to avoid excessive moisture on foliage, as prolonged wetness can promote the growth and spread of the disease.
2 - Treatment
• Unfortunately, wood infections caused by Measles cannot be cured. Once the wood is infected, the damage is irreversible. • Utilize fungicides such as benzovindiflupyr, boscalid, fludioxonil, pyraclostrobin, or thiophanate-methyl as preventive measures to minimize the risk of infection. • Seek guidance and advice from agricultural specialists or professionals experienced in dealing with Measles for effective management strategies. • In severe cases, consider implementing techniques like double pruning or grafting to renew the trunk and rejuvenate the vine, mitigating the impact of the disease.
