Biological control agent release
Aeschlimann J.P. (1989).
On the importance of assessing the quality of beneficial organisms mass-produced for use in biological control programmes against noxious plants and animals.
Boletin Sanidad Vegetal, Fuera de Serie No. 17: 377-382.
Examples are given illustrating the importance of continuous quality assessment of biological control agents, which have been mass-reared for field use, are described. Examples include the curculionid Rhinocyllus conicus which attacks thistle species and braconids in the genus Microctonus used to control curculionids.
Beirne B.P. (1975). Biological control attempts by introductions against pest insects in the field in Canada. The Canadian Entomologist 107: 225-236.
Cameron P., Hill R.L., Bain J., Thomas W.P. (1993). Analysis of importations for biological control of insect pests and weeds in New Zealand. Biocontrol Science and Technology 3: 387-404.
Cullen J.M. and Hopkins D.C. (1982).
Rearing, release and recovery of Microctonus aethiopoides Loan (Hymenoptera: Braconidae) imported for the control of Sitona discoideus Gyllenhal (Coleoptera: Curculionidae) in south eastern Australia.
Journal of the Australian Entomological Society 21: 279-284.
The braconid parasite Microctonus aethiopoides Loan was imported from Morocco in 1976 and released at sites in South Australia and New South Wales in 1977 and 1978 for the biological control of Sitona discoideus Gylh., a pest of lucerne and annual species of Medicago. Rearing, release and recovery methods are described, including techniques necessary to overcome the problems posed by aestivation of the host. The parasite has become established at several sites, and is a promising control agent with a high searching capacity and rapid rate of increase relative to its host.
Fauvergue X., Malausa J.-C., Giuge L. and Courchamp F. (2007).
Invading parasitoids suffer no Alee effect: a manipulative field experiment.
Ecology 88: 2392-2403
Populations released for biological control are similar to fortuitous invading populations and may therefore suffer from Allee effects, and since experimental manipulation of initial population size is possible, a unique opportunity to test for the occurrence of Allee effects is provided. The initial size of 45 populations of a parasitoid wasp introduced for the biological control of a phytophagous insect was measured monitored for three years. Results suggested an absence of Allee effects but clear negative density dependence instead: (1) the probability of establishment after three years was not affected by initial population size; (2) net reproductive rate was highest at low parasitoid density and high host density; (3) the sex ratio, reflecting the proportion of virgin females, did not increase at low density, suggesting that low densities did not impede matefinding; (4) the depression of host populations did not depend upon the number of parasitoids introduced.
Goldson S.L., McNeill M.R., Proffitt J.R., Barker G.M., Addison P.J., Barratt B.I.P. and Ferguson C.M. (1993). Systematic mass rearing and release of Microctonus hyperodae (Hym.: Braconidae, Euphorinae), a parasitoid of the Argentine stem weevil Listronotus bonariensis (Col.: Curculionidae) and records of its establishment in New Zealand. Entomophaga 38: 1-10.
Grandgirard J., Hoddle M.S., Petit J.N., Roderick G.K. and Davies N. (2008).
Engineering an invasion: classical biological control of the glassy-winged sharpshooter, Homalodisca vitripennis, by the egg parasitoid Gonatocerus ashmeadi in Tahiti and Moorea, French Polynesia.
Biological Invasions 10: 135-148
Pre-introductory risk assessment studies of Gonatocerus ashmeadi (Hymenoptera: Mymaridae) for use as a classical biological control agent against Homalodisca vitripennis (Hemiptera: Cicadellidae) in the Society Islands of French Polynesia.
Hopper K.R. and Roush R.T. (1993).
Mate finding, dispersal, number released, and the success of biological control introductions.
Ecological Entomology 18: 321-331.
Published data were analysed and a mathematical model of the population dynamics of introduced parasitoids were used to investigate the reason for failure of biological control introductions. Allee effects result in small populations becoming extinct because low densities lead to failure to mate, a male-biased sex ratio, and sometimes extinction. For many groups of parasitoids the proportion of populations that established increased with the number of parasitoids per release and the total number released. An analysis of past introductions and the reaction-diffusion model both suggested a threshold of about 1000 insects per release to ensure establishment of introduced parasitoids.
Ireson J.E., Gourlay A.H., Holloway R.J., Chatterton W.S., Foster S.D. and Kwong R.M. (2008).
Host specificity, establishment and dispersal of the gorse thrips, Sericothrips staphylinus Haliday (Thysanoptera: Thripidae), a biological control agent for gorse, Ulex europaeus L. (Fabaceae), in Australia.
Biological Control 45: 460-471
Sericothrips staphylinus was released as a biological control agent for Ulex europaeus in New Zealand and Hawaii following tests which showed it was narrowly oligophagous. To determine the suitability for release in Australia, further host specificity tests were conducted on Australian plants which confirming host specificity and it was released in Tasmania during January 2001. Releases of 10, 30, 90, 270 and 810 adults showed that establishment could be achieved with as few as 10 thrips. 250 thrips were chosen as the minimum number for release because this release size produced close to the maximum population growth. Surveys in early 2007 recovered S. staphylinus from 80% of 30 sites in Tasmania, but densities were low with no evidence of visible plant damage. The survey results indicated that S. staphylinus is a sedentary, latent species characterised by steady densities and low levels of damage to its host plant. Its efficacy as a biological control agent on gorse may be restricted primarily by 'bottom up' effects of plant quality limiting its rate of natural increase and an inability of the thrips to reach large, damaging populations under field conditions.
Memmott J., Fowler S.V., Hill R.L. (1998). The effect of release size on the probability of establishment of biological control agents: Gorse thrips (Sericothrips staphylinus) released against gorse (Ulex europaeus) in New Zealand. Biocontrol Science and Technology 8: 103-115.