In the case of the two rabbit viruses, virus-host co-evolution has led to a decline in effectiveness of the viruses over time as they lost virulence and rabbits developed resistance to them. These two factors can slow and even stop the agents building-up to sufficient levels to control the invasive species. Weather and climate can affect biocontrol agents, like all living organisms.

Biocontrol is not a вЂsilver bulletвЂ™Д«iocontrol will not solve all problems to do with invasive species. ThatвЂ™s because we have to find suitable candidate agents overseas, test them for safety in quarantine, and comply with regulations around release.Д«ut once biocontrol agents are released and affect the invasive species across its range, follow up control costs are greatly reduced. The initial costs of biocontrol programs are generally high. This is the only example of a successful large-scale biocontrol program against a vertebrate pest anywhere in the world. ItвЂ™s estimated that the benefit of rabbit biocontrol to agriculture is worth more than A$70 billion. Together, they have kept rabbit numbers well below the devastating pre-1950s levels. Myxoma virus was released in 1950, followed by rabbit calicivirus in 1995, causing regular disease outbreaks in wild rabbits. CSIROД«iocontrol has also proven to be the only effective way to significantly reduce European rabbits across Australia. The invasive plant bridal creeper affected by its rust fungus. Cactoblastis has been keeping prickly pear under control almost by itself to this day. Biocontrol was initiated in the early 1900s and the prickly pear moth, Cactoblastis cactorum, was introduced in 1926 from the pearвЂ™s native home in the Americas. The plant was introduced into Australia in the late 1770s and grown in a few areas of NSW and Queensland until it became invasive after rapidly spreading following the flood of 1893. Prickly pear is a perfect success story of biocontrol. Many biocontrol agents of plants and insects, once established, are self-sustaining and donвЂ™t have to be reapplied. Other control methods, such as the use of poisons and mechanical removal, require continued reapplication. This demonstrates that it will not pose unacceptable risks to domestic, agricultural, and native species. To be allowed entry into Australia, a candidate biocontrol agent must be assessed using internationally-recognised protocols. To protect against such harmful mistakes, Australia now has world-leading biosecurity import regulations and an effective quarantine system. Building on these examples, the paper will discuss the environmental impact assessment of modification processes and further development needs.But do they work? Learning from the cane toad catastropheД¬ane toads, which were introduced in 1935 to control cane beetles in QueenslandвЂ™s sugar cane crops, are probably the most infamous example of biocontrol going wrong in Australia.Д«ut AustraliaвЂ™s borders were more open back then.

In this paper, three groups of wood modification processes are discussed and exemplified with modified wood products that have been newly introduced to the market: (i) chemical processing (acetylation, furfurylation, resin impregnation etc.) (ii) thermo-hydro processing (thermal treatment) and (iii) thermo-hydro-mechanical processing (surface densification).

The different wood modification processes are at various stages of development, and the challenges that must be overcome to expand to industrial applications differ amongst them. As a result, wood modification has been implemented to improve the intrinsic properties of wood, widen the range of sawn timber applications, and acquire the form and functionality desired by engineers, without bringing environmental friendliness into question. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials should be included in planning by considering the entire life cycle and embodied energy of the materials used. This increased interest depends partly on the restricted use of toxic preservatives due to increased environmental concern, as well as the need for reduced maintenance for wood products that are mainly for exterior use. The market for new durable products of modified wood has increased substantially during the last few years, especially in Europe.

The alternatives of biocontrol agents