| Summary: | 碩士 === 國立中興大學 === 昆蟲學系 === 82 === Four available substances including molasses, protein
hydrolysate, yeast powder and Shao-Shing wine-dreg were
selected and tested for attracting the oriental fruit fly,
Dacus dorsalis Hendel, by screening their concentrations, mixed
each other with various ratios and acting with microorganisms.
It showed that the most effevtive concentration was 30% for
yeast powder with which the high attractiveness of 39.7% was
obtained in luring this fly, and for molasses it was 50%, at
which it was the only one that attracted to females more than
to males among all the tested substances. The best
concentration for protein hydrolysate was 70% while 50% for
Shao-Shing wine-dreg. When substances mixed with each other by
various mix ratios, it is found that the most effective mix
ratio for each substance in attracting flies was 7:3 for yeast
powder mixed with protein hydrolysate, 7:3 for yeast powder
mixed with molasses, 5:5 for protein hydrolysate mixed with
molasse. Except Shao-Shing wine-dreg, the attractiveness of
mixtures of the other three substances were all higher more
than 1.3 times than each substance used alone. In testing of
attractants acted by "ftuit fly type"bacteria, it showed that
protein hydrolysate metabolized by Enterobacter cloacae had a
high percentage of attraction(60.3%)to the laboratory-reared
fly individuals, which was 2 times higher than the uninoculated
attractant, however, when tested in guava orchard, it is found
that the protein hydrolysate inoculated by Citrobacter freundii
was the most effective one to the wild flies, 49.7 flies
attracted per day, showed the most effective attraction among
all the attractants acted by microorganisms in this test.
Molasses with 50% concentration decomposed by Aspergillus
oryzae var. effusus (3.68x106) for one day had 61.3% of
attractiveness, while the same material inoculated by A. oryzae
var. effusus and Saccharomyces cerevisiae and fermented for 4
days, had increased the attractiveness to 64.7%, 1.7 times
better.
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