In-Vitro Evaluation of Antagonistic Trichoderma Strains for Eradicating Phellinus Noxius In Colonised Wood

[EN] The aim of the present in vitro studies was to identify Trichoderma strains from Hong Kong with highly antagonistic potential against the basidiomycete Phellinus noxius (Corner) G. Cunn. Dual culture and interaction tests using samples of balsa wood (Ochroma lagopus Sw.), as well as studies on fungal growth at different temperatures and water activities, were conducted. The impact of Trichoderma strains on wood colonisation and decomposition by three P. noxius isolates were quantitatively analysed by measuring dry weight loss and the rate of eradication of the pathogen from the test wood. Most Trichoderma strains revealed antagonistic potential against P. noxius in these in vitro studies. In the wood blocks incubat-ed with P. noxius and then treated with Trichoderma T-TMS1 for 24 weeks, 100% eradica-tion of three P. noxius isolates was recorded. The results indicate that the application of Trichoderma strains may be a promising and environmentally benign method of eradicating P. noxius from wood debris in soils.We thank Muni Arborist Limited for assisting in the preparation of wood materials, use of facilities and support. Financial and technical support for project WQ/054/12 provided by The Chinese University of Hong Kong and Tree Management Office of the Development Bureau (Works Branch) of Hong Kong Government is gratefully acknowledged.Ribera Regal, J.; Tang, A.; Schubert, M.; Lam, R.; Chu, L.; Leung, M.; Kwan, H.... (2016). In-Vitro Evaluation of Antagonistic Trichoderma Strains for Eradicating Phellinus Noxius In Colonised Wood. Journal of Tropical Forest Science. 28(4):457-468. http://hdl.handle.net/10251/150303S45746828

Influence of incubation time on the vibration and mechanic properties of mycowood

The goal of the current study was to investigate the physical and mechanical properties of mycowood as a high quality tone-wood, obtained from Norway spruce by treatment of the white rot fungus Physisporinus vitreus as a function of the treatment time. In focus was the stiffness to weight ratio, which is often considered a main criterion for tone-wood selection. The vibro-mechanical properties were tested by non-destructive methods. The change of color and density were also measured after 4–12 months of fungal incubation. Density decreased up to 5% after 12 months of fungal treatment. Sound velocity was measured in small size specimens by means of the free-free vibration approach, while in large specimens the air-coupled ultrasound method was applied. The two techniques gave similar results and indicated that the sound velocity decreased in mycowood. Internal damping was increased in mycowood to a higher extent than the reduction in the specific modulus of elasticity (E/ρ) and thus the sound velocity in the material. The sound velocity was decreasing with increasing incubation times and scattering of data with this regard was larger in the transversal than in the longitudinal direction. The sound radiation coefficient and the characteristic impedance were enhanced in mycowood and its color was more brownish and richer in tone

Development of disease-suppressive organic growing media

Vigorous seedlings are an important base for vegetable production. Beside the availability of appropriate amounts of nutrients, the health of seedlings is decisive. Soil-borne diseases are a challenging problem in organic seedling production. Here, we present results on the development of disease-suppressive growing media. Three aspects were examined: (i) use of different components of growing media (peat, coconut fiber, wood fiber, compost), (ii) influence of selected organic nitrogen fertilizers and (iii) use of different microorganisms (including commercial biocontrol agents (BCA)). Three plant-pathogen systems were used in this study: cucumber-Pythium ultimum, cress-Pythium ultimum and basil-Rhizoctonia solani. Green waste compost showed a good capability to protect cress against P. ultimum. This effect was improved by using a chitin-containing N-fertilizer. However, an inappropriate storage of the compost diminished its efficacy. In contrast to coconut fibers, wood fibers showed a suppressive activity against P. ultimum when used as partial substitutes of peat. None of five tested commercial BCAs could improve the suppressiveness of the substrates against P. ultimum. However, one of newly tested strains of Trichoderma sp. was very suppressive against P. ultimum. The tested growing media showed only small differences in suppressiveness against R. solani on basil. In contrast, two of the new strains of Trichoderma sp., which were intermediately active against P. ultimum, could efficiently protect basil against R. solani. At the moment, we test combinations of different Trichoderma strains, compost, different types of peat and peat substitutes. The aim is to determine whether it is feasible to manufacture growing media which allow the production of healthy and robust seedlings also in the presence of high levels of pathogens

Podridão-do-lenho em plantios homogêneos de Acacia mangium Heartrot in homogeneous stands of Acacia mangium

O objetivo deste trabalho foi relatar a ocorrência da podridão-do-lenho em plantios homogêneos de Acacia mangium no Estado de Roraima. A observação dos sintomas iniciais em ferimentos de poda indica que a desrama artificial é um fator de predisposição. Estimativas realizadas em dois talhões comerciais constataram cerca de 8 e 39% de incidência da doença em árvores de três anos. Isolamentos a partir de árvores sintomáticas e testes de patogenicidade demonstram que Lasiodiplodia theobromae pode contribuir no processo de podridão. Este é o primeiro relato da podridão-do-lenho em A. mangium no Brasil, o que pode limitar sua exploração comercial.<br>The objective of this work was to report the occurrence of heartrot in homogeneous stands of Acacia mangium in the State of Roraima, Brazil. Observations of symptoms initiating from pruning wounds indicated that the artificial pruning is a predisposing factor. A survey carried out in two commercial stands showed 8 and 39% of disease incidence in three-year-old trees. Isolations performed from symptomatic trees and pathogenicity tests demonstrated that the fungus Lasiodiplodia theobromae can incite the rot development. This is the first record of A. mangium heartrot in Brazil. The disease can restrict its commercial exploration