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In vitro studies on the effect of chitosan on mycelial growth and spore germination of decay fungi, moulds and staining fungi
2004 - IRG/WP 04-10507
The effect of solubilised, low molecular weight chitosan on established mycelial growth of a range of decay fungi, moulds and staining fungi was investigated using nutrient medium amended with different concentrations of chitosan that ranged from 0.1 to 0.4% weight per volume (%w/v). Also, spore germination of Trichoderma harzianum and Leptographium procerum was examined on chitosan amended nutrient medium using visual and microscopic assessment. The results showed that chitosan affected mycelial growth of a wide range of test fungi which generally showed lower growth rates as the chitosan concentration increased. However, the degree of inhibition exhibited by chitosan varied with fungal species. Under the present test conditions, chitosan was fungistatic, but not fungitoxic, against established mycelium of the staining fungi tested and also two moulds, Botrytis cinera and Cladosporium herbarum, but not against any of the decay fungi tested. Spores of T. harzianum germinated on chitosan amended nutrient medium at all chitosan concentrations tested, except for the highest level (0.2%w/v) used, while L. procerum failed to germinate on 0.15 and 0.2%. Also, T. harzianum and L. procerum spores incubated on 0.15% and 0.2% chitosan failed to germinate when placed onto fresh malt extract agar suggesting fungitoxic activity of chitosan at these higher concentration levels.
C Chittenden, B Kreber, N McDowell, T Singh

Future Directions for Biological Control & BioActivity
2001 - IRG/WP 01-10416
Future directions for biological control of deleterious organisms on wood, and commercial market success, are dependent upon efficacy, cost and shelf life in comparison to other available means, and appropriate fulfilment of registration requirements. Basic and applied research involving ascomycete and/or basidiomycete fungi are described regarding solid wood applications of biocontrol of sapstain, and pulp and paper applications of pitch removal. Crucial to the efficacy assessment for the biological control agent is methodology to determine deterioration and diagnostics. Critical parameters that affect biological control efficacy in the field from our experience are as follows: 1. Cause of the deleterious condition, including presence of deleterious organism(s) and/or the environment in which they thrive. 2. Biochemical activity and growth characteristics of the biological control agent, what we call BioActivity. 3. The wood resource and the environment in which it needs to be controlled.
R L Farrell, J M Thwaites

Bioactivity of Eucalyptus camaldulensis essential oil against Microcerotermes diversus (Isoptera: Termitidae)
2013 - IRG/WP 13-30631
Microcerotermes diversus Silvestri (Isoptera: Termitidae) is the most economically destructive wood pest in structures in Khuzestan province (Iran). Chemicals such as essential oils and plant extracts that are compatible with the environment and that have high potential to be used in integrated pest management programs are extremely important. This study evaluated the repellency, contact and digestive toxicity of Eucalyptus essential oil in no-choice and choice bioassays and feeding inhibition trials on M. diversus. Concentrations of the essential oil ranged from 0.3 to 1.6 % (g cc-1). The results of the choice tests and feeding inhibition trial showed that the essential oil could act as a repellent at the given concentrations. Concentrations used in these tests resulted in mortality of termites, and a direct relationship between concentration and mortality was observed. The essential oil also increased the mortality of termites at concentrations higher than 0.7%. Termite feeding decreased with increased in concentration. Due to the ability of termites to choose the untreated filter-paper in the choice trial, values of LT and LC, were higher than in no-choice trials. The highest effects of Eucalyptus essential oil (≈100% mortality) was induced by the concentration 1.6%. Overall, this study reveals that Eucalyptus essential oil may be suggested as an effective toxicant with suitable contact and digestive toxicity and repellent effects on M. diversus.
B Habibpour, E Shafiei Alavijeh, A Rasekh