| Summary: | 碩士 === 國立臺灣大學 === 植物病蟲害學系 === 85 === Abstract
The time required for an adult oriental fruit fly to reach sexual
maturation was observed in growth chambers at various rearing conditions,
namely 16, 20, 25, and 35℃ with a fixed photoperiod of 12L:12D. Both
female and male fly took about 6 to 8 days after emergence to reach sex
maturation between 25 and. At 16℃, female matured nine days faster (18
days vs. 27 days) than male. However, at 20℃, male matured one day
faster (11 days) than female (12 days). From 25℃ to 30℃, the sex
maturation rate of both female and male was not different, being six to
eight days. But at 35℃, male matured faster (6.0 days) than female
(6.7 days). The calculated development threshold at the temperature from
16℃ to 30℃ was 9.80℃ and 11.76℃ for female and male, respectively.
Flies of either single sex or both sexes were released in the net house,
results showed that both sexes prefer to rest on guava than on bamboo, and
the preference ratio was thrice and twice for female and male, respectively.
In any case, females rested on guava was more frequent than males, being 1.8
and 2.3 times in single sex and both sexes release, respectively. Mated
females showed higher tendency to rest on guava than other sexual maturity
females. The number of females on guava increased in the presence of sex-
matured males, but not vice versa.
In the male annihilation area, the trap distance between methyl eugenol
traps was 30 m, and the trapped numbers of male fruit flies and percentage
of damaged fruits were recorded at 10-day intervals. Results showed that
after the last ten-day trap in April, the average temperature rose from
20.77 to 24.06℃, and the ripened fruits in the orchard increased gradually,
and the trapped numbers in the orchard increased to 15, the male fruit fly
in the bamboo bush moved to the orchard. During April to September, the
ripened fruits of a plant from 2.0 increased to 10.7 gradually, and the
number of males trapped as well as the percentage of damaged fruits increased
immediately thereafter. Judging from the various numbers of trapped males and
percentage of damaged fruits, it was evident that traps set at 30 m distance
apart in the male annihilation area could not intercept the invasion of the
oriental fruit fly into the orchard. Therefore, it could not indirectly
reduce the percentage of damaged fruits in the orchard.
In the combination trapping of methyl eugenol and yellow-colored sticky
traps set up at 20 m intervals, the results indicated that number of trapped
males by methyl eugenol trap per 10 days (26.2 males), was higher than in
male annihilation area (15.0 males), and by yellow-colored sticky trap were
31.6 and for female and male, respectively. During May to August, percentage
of damaged fruits on tree (71.76 %) was higher than in male annihilation area
(20.54 %), showed the effectiveness less than in male annihilation area. The
trapping record showed that in warmer and cooler months, the number of females
trapped was always higher than males. And the trapped ratio of female/male
during cooler months was twice as much as that of the warmer period.
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