AbstractIn a field experiment in central Sweden, the vigour of 25‐yr‐old Scots pines was manipulated by pruning, prior to inoculation withLeptographium wingfieldiiandOphiostoma minus, two blue‐stain fungi associated withTomicus piniperda. Our main purpose was to correlate fungus invasion and host defence reactions with host vigour. Both fungi invaded the inner bark and the sapwood at the points of inoculation.L. wingfieldiicaused larger lesions in the bark, but O.minustended to grow faster in the sapwood. The flow of primary resin was related to tree vigour, whereas carbohydrates present in needles and stem phloem were not. Lesion formation and the content or composition of resin acids in lesions did not differ between fungi or pruning treat