Diversity and population of thrips species on legumes with special reference to Megalurothrips sp. / Zafirah Zakri
Thrips (Thysanoptera) are a common pest on legume plants, yet little is known about their ecology or diversity in Peninsular Malaysia. In legumes, thrips are typically found in the flowers, where their feeding activity causes malformations that eventually lead to crop damage. The aim of this stud...
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| Format: | Thesis |
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2017
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| Online Access: | http://studentsrepo.um.edu.my/9573/ http://studentsrepo.um.edu.my/9573/2/Zafirah_Zakri.pdf http://studentsrepo.um.edu.my/9573/6/Diversity_and_population_of_thrips_species_on_legumes_with_special_reference_to_Megalurothrips_sp..pdf |
| Summary: | Thrips (Thysanoptera) are a common pest on legume plants, yet little is known about their
ecology or diversity in Peninsular Malaysia. In legumes, thrips are typically found in the
flowers, where their feeding activity causes malformations that eventually lead to crop
damage. The aim of this study is to examine the diversity and population of thrips species,
particularly Megalurothrips usitatus, in three selected legume farms around Peninsular
Malaysia (Janda Baik, Pahang; Bestari Jaya, Selangor and Jelebu, Negeri Sembilan).
Depending on growing season, legume flowers were inspected monthly for thrips in five
random plots from each farm for 6 to 12 months. Sampling was performed six times in
Bestari jaya and Jelebu, and twelve times in Janda Baik. The most abundant thrips species
on legumes was M. usitatus (89.97%) followed by Thrips parvispinus (9.77%), Thrips
hawaiiensis (0.13%) and Ceratothripoides brunneus (0.12%). Differences in legume
species, which is i.e. long bean, French bean and winged bean, did not affect the abundance
of M. usitatus, and the species was equally distributed among different arbitrary strata on
legume plants. Temperature and light intensity were found to be positively correlated with
the abundance of M. usitatus, but relative humidity showed negative relationship. M.
usitatus was found in large numbers during the hot and dry months, but in lower numbers
during the raining season. This suggests that the wet season may help to reduce populations
of M. usitatus on legume plants. The doubtful female individuals of M. usitatus were
obtained from the field and from the unmated female of lab rearing. There are 15.4% of
doubtful female of M. usitatus were produced from the unmated female. The molecular
analysis showed the doubtful females with several M. usitatus females belong to the sub
clade 2 which is in the same clade of M. typicus. Hence, at this stage, the doubtful female
could be considered as a cryptic species and a by-product from the unmated female. Thus, the present study is important for obtaining more information of M. usitatus on legume
crops in Malaysia, and thus to improve effective management strategies for this pest. |
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