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Title:	Plant volatile organic compounds (VOCs) profiles induced by various stimuli and their influence on the preference of whitefly, Bemisiatabaci (hemiptera: aleyrodidae) and its predator
Authors:	Khalid A. Saad Mustafa (P63195)
Supervisor:	Idris Abdul Ghani, Prof. Dr.
Keywords:	Volatile organic compounds Chilli plants Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	4-May-2017
Description:	The present study was undertaken to investigate the effects of various stimuli-induced responses in chilli plants on the host finding and acceptance by whitefly (WF), Bemisiatabaci(Gennadius) through a series of behavioural assays and analyses of headspace plant volatile organic compounds (VOCs) by gas chromatography coupled with mass spectrometry (GC-MS). The results showed that females of WF significantly (P < 0.05) preferred odour cues from non-infested chilli plants over plants infested with WF of the same or opposite sex (P < 0.05).In contrast,the number of males that responded to chilli plants infested by the same or opposite sex was not significantly different (P > 0.05) from those that responded to the non-infested plants.WFs preferably aggregated on undamaged chilli plants than on artificially damaged plants after 6 and 24 h of damage induction. Preference for subsequent oviposition on artificially damaged plants was reduced. The levels of volatile monoterpenes, i.e. α-pinene, p-cymene, and β-phellandrene in artificially damaged plants after 24 h were significantly different (P < 0.05) as compared to that in undamaged plants and artificially damaged plants after 1 h of damage induction. Furthermore, the presence of cucumber mosaic virus (CMV) in chilli plants affected the settling preferences of the non-vector B. tabaci, which preferred to settle on non-infected plants. The egg hatch duration and the longevity and fecundity of the adult WF on CMV infected chilli were not significantly different (P> 0.05) from those on non-infected chilli plants. However, the development time from egg to the adult stages was significantly (P < 0.05) reduced on the CMV infected plants compared to the non-infected ones, with significantly higher (P <0.05) released of linalool and phenylacetaldehyde in the infected plants. The potential effect of pre-infestation of chilli plants with aphids on the settling preference of WF was also studied. The female WFs preferred odour cues emitted by no aphid-infested plants than to the aphid pre-infested ones. Production of some VOCs emitted by the infested plants was significantly (P < 0.05) increased in the case of monoterpenes (cymene; 1, 8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate as compared to the non-infested plants. The effect of citronella (Cymbopogonnardus) essential oil on repellence and oviposition deterrence of WFs on chilli plants was also tested. Results showed that there was a significant oviposition deterrence, repellence, and toxicity for WF by the citronella essential oil. The olfactory response of predatory Macrolophuscaliginosus to the host plants infested with WF was also investigated. The results showed that preference was modified by previous experience of predators fed on infested host plants and shown strong preference for chilli plants infested with nymphs of WF compared to the non-infested and egg-infested plants.Overall, it could be suggested that the behavioural response of WF might be modified by the plant-induced responses, which alter the release of specific headspace volatiles. Based on these results, modification of volatiles that do not favour WF, via plant breeding, might enhance IPM of WF.,Certification of Master's/Doctoral Thesis" is not available
Pages:	196
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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