During the past decade, diagnostic methods for detecting incipient wood decay in vitro and in situ have been developed using antibodies to target fungal antigens. Antibodies are potentially ideal probes for detecting fungal biodeterioration because they are specific and can quantitate fungal antigens within a complex structure such as wood. Both polyclonal and monoclonal antibodies to various fungal components have been utilized separately and in concert for immunoblotting, enzyme immunoassays, particle agglutination assays, and chromatographic ˇ®dipstick' assays. This paper provides an overview of the challenges encountered and progress made in the field of forest products immunodiagnostics since 1986,

INTRODUCTION

Techniques for detecting biodeterioration of wood have traditionally included visual and microscopic examination (Wilcox, 1964), culturing of fungi from wood (Nobles, 1965), direct chemical staining (Eslyn, 1979), and sonic and electronic resistance methods (Dunlap, 1981; Shortle, 1982; Ross et al., 1994). Sounding of wood, radiography, and mechanical probing devices are still commonly used to detect advanced decay; however, early stages of decay are difficult to assess by any technique (Highley et al., 1994). Some techniques are designed to detect viable decay fungi, and others detect residual nonviable fungal metabolizes. All techniques require some specific skill or expertise for interpretation. Direct staining of core samples with chemical indicators has been somewhat successful in detecting early decay, but results are often ambig- 1The use of trade or firm names in this publication is for the reader's information and does not imply endorsement by the US Department of Agriculture of any product or service. 2The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by US Government employees on official time, and it is therefore in the public domain and not subject to copyright. uous (Highley et al., 1994). A common technique for differential histochemical staining, the Picro Analine Blue-Safranin staining procedure (Wilcox, 1964), is tedious and time-consuming, and differentiation between the wood cell walls and hyphae is often subjective (Clausen & Ferge, 1995). Culturing directly on agar medium is relatively simple (Nobles, 1965), but antibiotics must be incorporated to suppress bacterial growth. Even then, molds sometimes quickly cover the agar surface, obscuring the growth of wood decay fungi. Standard incubation times of 3 weeks are needed to allow for slow-growing fungi to appear. The Shigometer, an electronic-type detector that measures wood resistance, has been used to detect incipient internal decay in trees and utility poles (Shortle, 1982). This instrument gives unreliable results when the moisture content of the wood is greater than 38% (Morris & Dickenson, 1984). Wood that has lost only 1% of its weight because of decay will frequently exhibit a 50% loss in strength measured as toughness (Richards, 1954). Proper diagnosis of early decay allows for appropriate remedial treatment with preservatives to arrest decay prior to loss of structural integrity. In the past decade, researchers have successfully developed methods for detecting incipient wood.

• experiment: mycology study
• fungi and molds in buildings and their envelopes
• fungi: mycology studies, culturing
• wood, lumber, timber

1. Evaluation of wood treated with copper-based preservatives for Cu loss during exposure to heat and copper-tolerant Bacillus licheniformis