Methods for detecting early stage fungal infection (and especially esca or esca-like infections) in woody plants are disclosed, using X-ray tomographic imaging. In preferred embodiments, axial X-Ray tomography is employed, with radiodense regions of the tomograms indicating the location of such infection. The methods are particularly relevant to detection of esca in grapevine and kiwi. Methods for controlling such infections using such tomographic methods and direct introduction of fungicides are also disclosed.