Evaluation of wood treated with some natural extracts and Paraloid B-72 against the fungus Trichoderma harzianum: Wood elemental composition, in-vitro and application evidence

Abstract

The damage in wood is commonly associated with fungi which do not affect wood strength. This study investigates the in-vitro growth inhibition of Trichoderma harzianum, a well-known fungus, by different methanol extracts from selected tree species. We observed the hyphal growth by the environmental scan electron microscope (ESEM) and evaluated the changes in the elemental composition by the electron dispersive X-ray spectroscopy (EDX). The methanolic extracts of Morus alba heartwood and Maclura pomifera bark had significant effects (P < 0.001) on the linear growth of T. harzianum. The treated wood samples of Acacia saligna with the methanolic extract of Cupressus sempervirens wood showed an inhibition zone against the growth of T. harzianum around the treated wood at the concentrations of 5, 10, and 20%. However, ESEM and EDX analyses of treated wood demonstrated that the combination of Paraloid B-72 and the methanolic extract of C. sempervirens wood might be used as a potent biocide against the mold fungus T. harzianum.