Link to home

Silverleaf disease management on blueberry

Andres France: INIA Quilamapu

<div>Silverleaf disease (<em>Chondrostereum purpureum</em>) was described worldwide in blueberry cv. Brigitta Blue, in 2005, Osorno, Chile. Thereafter, the disease spread into the production area and to new cultivars. In 2014 was detected on rabbiteye, cv. Brithwell. Currently, there are 11 varieties of <em>Vaccinium corymbosum</em> and one of <em>V. virgatum</em> affected by the fungus. Silverleaf is difficult to control, because the fungus inhabits deep into the wood. The objective of this work was to evaluate different practices to control silverleaf in blueberry. Treatments were the pruning of symptomatic branches, in vitro test of fungicide and application to the crown, compost Tea applied through drip irrigation, and complete plant pruning at the crown level. Effectiveness was verified through foliar symptoms and ELISA test. The results showed that six out of 14 fungicides were highly active <em>in vitro</em>, but ineffective in plants. Branches pruning partially controlled the disease, because it appeared in the following seasons. Compost Tea was able to delay symptoms expression and reduce the incidence (P< 0.05), but the pathogen was still present. Finally, the complete pruning of the aerial part was the only treatment able to eliminate the pathogen. New sprouts were asymptomatic and pathogen free. Thus, <em>C. purpureum</em> colonize stems and crown heart but not the root system, therefore when the crown heart was exposed to the sun light the pathogen died, making possible the growth of healthy shoots.</div>