Identification and biocontrol potentials of entomopathogenic fungi and their endophytic effects against Bemisia tabaci gennadius on tomato, Solanum lycopersicum linn
Tomato, Solanum lycopersicum is a plant-vegetable fruit that is widely grown throughout the world due to its nutritive and health benefit. It is a common and popular vegetable in Malaysia, produced and managed largely by smallholders’ farmers, and provides thousands of employments for the peoples...
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| Format: | Thesis |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/104559/1/FP%202022%2022%20IR.pdf |
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| Summary: | Tomato, Solanum lycopersicum is a plant-vegetable fruit that is widely grown throughout
the world due to its nutritive and health benefit. It is a common and popular vegetable in
Malaysia, produced and managed largely by smallholders’ farmers, and provides
thousands of employments for the peoples. However, insect pests including whitefly,
Bemisia tabaci are the major constraints in tomato productions. The application of
chemicals is the most efficient option to protect tomatoes against pests and diseases,
despite various adverse effects reported on non-target organisms, including beneficial
insects (pollinators), livestock and humans. In recent years, researchers have shown an
increasing interest in the possibility of using biological control agents including
entomopathogenic fungi (EPF) as an alternative to chemical control measures. In
addition to direct application to control insect pests, EPF can colonize plant tissues and
grow endophytically, benefiting their host plant without causing any symptoms or
negative effects. Entomopathogenic fungi were isolated from soil using the insect bait
method with mealworm beetle (Tenebrio molitor) and from infected B. tabaci infesting
vegetables. All the isolates were identified based on morphological characterization and
molecular identification using Internal Transcribed Spacer (ITS) region. The in vitro
entomocidal activity of the three Metarhizium anisopliae isolates was evaluated against
B. tabaci at different incubation temperatures (15, 20, 25, and 30⁰C) using a
concentration of conidia, 1x107conidia/mL. Meanwhile, the virulence of two isolated
fungal species, Cordyceps javanica and Purpureocillium lilacinum were evaluated
against B. tabaci under laboratory and glasshouse conditions. Furthermore, the effect of
tomato seed treated with EPF on plant growth, mortality, and population of B. tabaci
were evaluated using the seed inoculation method. A total of 12 isolates of
Entomopathogenic fungi (EPF) were identified out of M. anisopliae (seven isolates) and
P. lilacinum (two isolates) found from a soil sample, while species C. javanica (two
isolates) and P. lilacinum (one isolate) isolated from infected B. tabaci. The percentage
mortality of the three isolates of M. anisopliae (Ma-2b, Ma-9a and Ma-15) tested against
B. tabaci with an average mortality rate 36.1% - 97.7% at different temperatures (15, 20,
25, and 30⁰C) at 7 days post-treatment. The isolates Ma-15 caused the highest percentage mortality of 97.7% and analysis of LT50 and LT90 shows an increase in mortality (1.6 and
3.9 days respectively), at 30⁰. Moreover, the experiment conducted with C. javanica and
P. lilacinum indicated that each of the isolate significantly (p< 0.05) reduce the
population of adults and nymphs B. tabaci under laboratory and glasshouse conditions.
Our study also revealed that tomato seed treated with C. javanica and P. lilacinum
allowed their recovery 60 days after inoculation (DAI). Both endophytic isolates also
reduced the population and adult emergence of B. tabaci compared to control treatment.
Findings from this study recommend that locally isolated entomopathogenic fungi have
the potential to be developed as biopesticides in the future to control whiteflies on tomato
plants. The use of entomopathogenic fungi as one of the elements of Integrated Pest
Management (IPM) can reduce dependence on the use of chemical pesticides, being
environmentally friendly and turn ensuring food safety. |
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