Metarhizium Anisopliae Metch. Sorrokin as a Potential Microbial Control Agent Against the German Cockroach, Blattella Germanica (L.) (Dictyoptera:Blattellidae)
The German cockroach, Blatella germanica (L) is an important urban insect pest in many parts the world. In Malaysia, It is abundant in hotels and food preparative outlets. Several methods are being used to control this pest and the most common method is using chemical insecticides. The use of che...
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| Format: | Thesis |
| Language: | English |
| Published: |
2004
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/249/1/549494_FH_2004_11.pdf |
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| Summary: | The German cockroach, Blatella germanica (L) is an important urban insect pest in many
parts the world. In Malaysia, It is abundant in hotels and food preparative outlets. Several
methods are being used to control this pest and the most common method is using
chemical insecticides. The use of chemical for controlling cockroaches , however, has
incurred a serious drawback. The cockroach population in many parts of the world
developed resistant to chemical insecticides. Thus alternative methods for controlling are
warranted. One of these methods is the use of biological agents such as
entomopathogenic fungus, Metarhizium anisopliae.
In this study eleven indigenous isolates of M. anisopliae were evaluated for their
pathogenicity to adult male of German cockroach. Monoconidial cultures of the isolates
were obtained from soil and insect cadaver that were collected from various localities in
Malaysia and were maintained on Potatoes Dextrose Agar+Yeast (PDAY).The result from the screening test shows that from eleven isolates tested, HSAH gave the
best result with 87.5% mortality after 13 days inoculation and LT50 values of 6.78 days.
Although not significantly different, there was a tendency for mortality on nymphs to be
higher than mortality on adult males and females.
Further bioassay on four selected isolates, HSAH, Mam, Ckrk, LPR3, shows that the
infectivity of the fungus varied with the isolates and dosages to which the cockroaches
were exposed. The ED50 values ranged from 2.73 x 109 to 3.15 x 1011 at day 4 after
inoculation and 4.19 x 103 to 1.22 x 106 at day 14 after inoculation, the LT50 values
ranged from 12.37 to 16.45.
The result evidently shows that HSAH isolate was the prominent isolate. Using HSAH
isolate to control a cockroach colony, the result shows that highest mortality of 78.5 %
was achieved when a colony of 50 insects were used and with dosage of 10:90. The same
level of mortality i.e 78.5 % could not be achieved by a colony of 100 insects when
applied with a dosage of 10:90. Apparently with a bigger cockroach colony, a higher
dosage of fungus was required to kill B. germanica |
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