Blackline
cherry leaf roll virus
What is the Blackline Cherry leaf roll virus)?
Blackline, associated with the Cherry leaf roll virus (CLRV), affects cherry trees. Symptoms include poor terminal growth, yellowing leaves, premature defoliation, dieback of shoots, and profuse suckering. The black line or canker forms at the graft union on rootstock, eventually girdling and killing the scion in 2 to 6 years.
How does Blackline Cherry leaf roll virus) occur?
Cherry leaf roll virus (CLRV), spreads through infected pollen and root grafts. Pollen from infected trees can introduce the virus into orchards, and it spreads further when the flowers are ready for pollination. Additionally, infected, and healthy trees connected by root grafts can transfer the virus. Once inside the trees, the virus reproduces and produces more virus particles, which can then infect other susceptible trees through various means.
Symptoms
1 - Impacts on Plants
• Blackline disease can lead to the decline and death of infected trees over a period of 2 to 6 years. • The virus kills the tissues responsible for nutrient and water transport, resulting in stunted growth, decline of terminal shoots, and reduced fruit production.
2 - Impacts on Soil and Environment
• In the soil, the disease is primarily spread through root grafts, potentially affecting neighboring trees. • The spread of the disease can impact the environment by reducing walnut tree populations and disrupting the ecological balance within affected areas.
Solutions
1 - Preventive Measures
• Use certified virus-tested nursery stock to ensure the planting material is free from CLRV and other known viruses. • Select resistant or tolerant rootstocks, such as 'Paradox' or 'Vlach' rootstocks, which can help mitigate the spread and impact of CLRV. • Implement proper sanitation practices, including disinfecting tools and equipment, to prevent the transmission of the virus.
2 - Disease Management Strategies
• Regularly monitor walnut trees for symptoms of blackline disease, such as poor growth, yellowing leaves, and dieback. • Immediately remove and destroy infected trees to prevent further spread of the virus. • Control insect vectors that can transmit CLRV by using integrated pest management techniques, including insecticides and cultural control methods. • Maintain overall tree health through proper nutrition, irrigation, and pruning practices, as healthy trees are more resistant to diseases.
