A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
A request was received from a PestNet member, following discussion (elsewhere) on the use of meal worms (Tenebrionidae – generally “Tenebrio monitor“, though there are other species sometimes involved) and “black soldier fly larvae” (Hermetia illucen) as high protein feed for poultry, pigs and fish. Further details on rearing methods were requested from Samoa where these insects may have potential for the use in subsistence livestock farming.
Information from members suggested that T. monitor is ‘pretty’ rare in the Pacific – there is an old Lever record from Fiji of Tenebrio. It is also not common in New Zealand nowadays, although another species, Alphitobius sp. seems to be common. Hermetia illucens is common throughout the Pacific – it is the large black fly with two white “windows” on its abdomen. It is already in Samoa.
Concern was raised about using these insects for animal feed as they might cause irritation of the digestive tract when in large numbers and some allergic reactions. Other members could not recall such reactions.
While this method of production of a protein source was thought to be innovative, members wondered why conversion of waste yeast from the Vailima Brewery (Samoa) into a protein source as a supplement to animal feeds was not been investigated as an alternative. The Royal Brewery in Tonga and the Tusker Brewery in Vanuatu have set up, with some assistance from the Project on Regional Management of Fruit Flies in the Pacific (RMFFP) and ACIAR, a process to convert brewery waste yeast into a usable protein for fruit fly control. There is excess protein to the requirements for fruit fly control, which can be used as an inexpensive additive to animal feed. The process of heating the waste yeast to kill and rupture the yeast cells and adding the enzyme papain plus a food preservative such as potassium sorbate to increase shelf-life, concentrates the protein to at least 30%. A brief description of the process is contained in Lloyd, A.C. and Drew, R.A.I. (1997). Management of Fruit Flies in the Pacific, ACIAR Proceedings No 72, pp. 192-198. See www.pacifly.org to get information.
Another advantage of converting brewery waste yeast is that this material is no longer discharged into the marine environment. In most Pacific Island countries and territories, where breweries exist, the untreated brewery waste yeast (probably around 15-16% protein) is discharged into the sea. Not only is this a pollutant that could be avoided, but also this represents a waste of a valuable protein source in an area where readily available protein is short supply. The waste yeast technology is simple, relatively inexpensive, and can be adopted by any country that has a brewery.
The experience of Vietnam was somewhat different and concerns the yellow meal worm beetle (Tenebriomonitor L.). From about 1996, some people illegally imported yellow meal worm beetle from China for feeding to birds. After researching (1996-1998), we found a low risk potential for this insect, which did not satisfy the definition of a quarantine pest. But before this time, some farmers produced larvae from a common pest (Alphitopius laegavitu) for feeding fish and birds. We are encouraging the use of local insects, and in the process discouraging the importation (legally as well as illegally) of those that might be potential pests.