Development of a mass rearing technique for the Tasmanian brown lacewing, Micromus tasmaniae Walker
Abstract
Aphids are one of the most important insect pests of greenhouse crops yet to be controlled by
biological means. Broad spectrum chemical control is becoming increasingly difficult to use in integrated pest management programmes, therefore, there is a need for a suitable biocontrol
agent to be mass reared and released.
The Tasmanian brown lacewing, Micromus tasmaniae Walker is an aphid predator that is
found commonly throughout Australasia and has suitable characteristics that make it a
candidate for mass rearing.
A technique for rearing M. tasmaniae was developed. Eggs of M. tasmaniae were reared in
batches of 50, 100 and 200 in 20 litre clear plastic containers. The oat aphid, Rhopalosiphum
padi L. was fed to the larvae. The results revealed that the highest initial egg density (200
eggs per container) produced the cheapest adults at 22 cents per adult. However, mass rearing
adults was considered not practical because of the high production cost, although, mass
production of eggs is considered to be economically viable. The cost of producing one egg
was 0.015 cents.
M tasmaniae was maintained in mass culture for six generations. Simple experiments were
carried out to monitor the quality of laboratory-reared insects. The 'wild' insect was used as a
quality standard and comparisons with laboratory-reared insect populations were made. The
fecundity, development rates and tolerance to pirimicarb, a carbamate insecticide, were
determined.
Fecundity was found to decline with successive generations in mass culture. The lacewing
development experiment indicated that larval stages of each generation suffered the highest
mortality rate and that between 35-45% of individuals emerged as adults. The tolerance of adults to pirimicarb did not alter over five generations.
Recommendations for improving the mass rearing of M. tasmaniae are discussed.... [Show full abstract]