The biological control potential of Cryphonectria parasitica strains containing an infectious cDNA copy of hypovirus CHV1-Euro7

Transmissible hypovirulence has not become established in most areas of North America as it has in Europe where it has been associated with increased biological control of chestnut blight. Transgenic strains of Cryphonectria parasitica provide several mechanisms that may improve biological control. This study was designed to evaluate whether transgenic C. parasitica strains containing a cDNA transgene encoding the viral genome of CHV1-Euro7 show greater potential to biologically control blight than their cytoplasmically infected counterparts. Three treatments were employed that compared: transgenic hypovirulent strains (TG), cytoplasmic hypovirulent strains (CH), and virulent strains (V). Two types of cankers were initiated in the study: punch initiated (PI) cankers to produce ascospores and scratch-initiated (SI) cankers to produce conidial inoculum. Ascospore contents from collected perithecia were diluted and cultured in the winter of 2004-2005 and pigmentation and morphology then were recorded for all three plot treatments (TG, V, and CH). (Abstract shortened by UMI.)...