Stump protection against Fomes annosus

Abstract

SUMMARYInoculation of pine stumps with oidia of Peniophora gigantea directly after felling gives good protection against Fomes annosus. With the largest inoculum of F. annosus spores likely to occur naturally, a dosage of 1 × 104oidia suffices for stumps having a wood‐diameter of 16 cm. P. gigantea enters the lateral roots of inoculated stumps and tends to check advance of F. annosus in any tissues infected at the time of felling; it also replaces this fungus to some extent, Lignin is rapidly decomposed and sporophores are generally produced within a year. Suspensions may conveniently be applied by a compressed air sprayer. Owing to the selectivity of freshly cut stumps, contamination of the suspension is not a serious hazard.If widely used, the method would necessitate large‐scale production of suitable inoculum sources. For most of the experimental work undertaken the inoculum was derived from wood‐block cultures of P. gigantea stored in polythene bags, but for routine use a more compact source would be preferable. A method is described for preparing tablets which, when dissolved in IOO ml. water, yield suspensions containing up to 1 × 106viable oidia per ml.: if kept at 10° C. they should each provide inoculum for more than a hundred stumps over a storage period of 10–20 weeks.The relative merits of inoculation and chemical treatment for control of F. annosus in pine stumps are briefly discussed and other possible applications of stump inoculation are outlined.