Two wood preservatives, N-nitroso-N-cyclohexylhydroxylamine aluminium salt(NCH-Al)and potassium salt (NCH-K) were examined on the mycostatic effect against three wood rotting fungi (Tyromyces palustris (Berk. et Curt.), Coriolus versicolor (L. ex Fr.) Quél and Polystictus sanguineus (L.) Fr.) and six molds (Aspergillus niger ATCC 6275, A. flavus ATCC 6943, Penicillium Citrinum ATCC 9849, Rhizopus nigricans S. N. 32, Cladosporium herbarum IAM F517 and Chaetomium globosum ATCC 6205) and sporostatic effect against six molds. Their mycostatic effect showed following sequence NCH-K>NCH-Al>Na-PCP and their sporostatic effect did Na-PCP>NCH-Al>NCH-K. Mycostatic effect of NCH-Al and NCH-K seemed to be more remarkable than sporostatic effect of them, and therefore, fungal resistance of NCH-Al and NCH-K is likely to be based on their mycostatic effect than sporostatic effect.
Fungal resistance of Sugi (Cryptomeria japonica D. Don) sapwood and bamboo (Phyllostachys pubescence Mazel) stem treated with NCH-Al and NCH-K was examined according to JIS Z 2911. The Sugi sapwood specimens treated with 1.0% NCH-K solution or 2.0% NCH-Al solution by dipping process showed satisfactory fungal resistance to molds for a period of 66 days.
The decay resistance of NCH-Al and NCH-K against T. palustris and C. versicolor was tested according to JIS A 9302. Decay resistance of specimen treated with NCH-Al was greater than that with NCH-K and showed satisfactory durability to decay at the retention of 1.44 kg/m³, even with preliminary weathering. When phenolic compound in walman salt was replaced with NCH-K, the specimen treated with 2.0% of this modified walman salt solution by pressure process showed satisfactory durability to decay without preliminary weathering.

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