Natural Enemies of True Fruit Flies (Tephritidae) - USDA - aphis

Jeffrey N. L. Stibick
Parasites and Predators - TABLE 2
7. Failure to adequately document efforts, no prerelease surveys,
lack of published records, and failure to properly evaluate
releases
Improving future classical biological control efforts
1. Retesting, with improved rearing methods, those species which
were unsuccessful in the past
2. Trying, with improved rearing methods to raise more difficult
parasitoids that were avoided in favor of easily reared species
3. Make more direct releases for field evaluation, rather than
emphasis on laboratory colonization
4. Complete studies on the biology of the natural enemies to be
utilized
5. Collect data to document impact of these parasitoid releases in
reducing the targeted fruit fly population densities
There has been a gradual shift from classical biological control to
augmentative biological control with mass rearing and the inundative
release approach (Wong, et al., 1991; Gingrich, 1993). This effort may
address some of the perceived shortcomings of classical biological
control in the context of a program effort for dealing with an invasive
pest and it does seem to have its advantages in dealing with a massive
pest population that is thriving in a new environment, by causing that
population to diminish rapidly or even crash. The purpose of releasing
such numbers is:
A. To eradicate the invading population.
B. To suppress the invading population over time and be self
sustaining
C. To control the invading population in as low numbers as is
possible and to augment biological control with sterile
releases of the fruit fly and/or releases of micoorganisms.
For this purpose, Ashley and Chambers (1979) did a study on
maximum rearing efficiency of Biosteres longicaudatus, on early
Anastrepha suspensa 3rd instar larvae. They concluded that with
ovipositional cages of size 24.5 cm 3 , maximum efficiency is reached at
a parasite density of 125 pairs of this species per cage, producing
1,896 progeny per 24 hr. exposure period.
Other approaches such as the release of pupal parasites to attack any
pupae of the target pest that survive other program efforts, such as
sterile release, biopesticides or other biotactical measures and/or
augmented parasitic releases of egg and/or larval parasites or
multiparasitism have been discussed. (Wong, et al., 1992; Bautista &
3-14 Natural Enemies of True Fruit Flies 02/2004-01
PPQ