Anais da Sociedade Entomológica do Brasil (2000) 29, 327-337

C.C. Ecole, M. Picanco, M.D. Moreira and S.T.V. Magalhaes (2000)
Componentes químicos associados à resistência de Lycopersicon hirsutum f. typicum a Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)
[Chemical components associated with resistance of Lycopersicon hirsutum f. typicum to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)]
Anais da Sociedade Entomológica do Brasil 29 (2), 327-337
Abstract: This work was carried out in a greenhouse at the Universidade Federal de Viçosa 'Campus', Minas Gerais, Brazil, between May and September 1997 and its objective was study the resistance of the accession LA 1777 of Lycopersicon hirsutum f. typicum to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and the compounds possibly involved in the resistance. The varieties Santa Clara (tomato for in natura consumption) and IPA-5 (industrial tomato) of Lycopersicon esculentum were used as pest susceptibility standards. The number of small and large mines (< 0.5 and > 0.5 cm long, respectively); survival; development stage; pupa weight; sexual proportion; fertility, and rate of larvae eclosion were assessed. Peaks of the ion current of hexane extract of tomato leaves and the possible compounds associated with them were identified using a gas chromatograph coupled to a mass spectrometer. L. hirsutum f. typicum showed resistance to the tomato leafminer in comparison with L. esculentum, which was reflected by the smaller number of large mines/ leaf and greater length of larval phase, mortality of larvae and number of small mines by T. absoluta. Fourteen peaks were identified in the total ion current with retention times ranging from 10.43 (peak 1) to 26.03 min (peak 14). The peaks 8, 9, 10 and 12 were associated with T. absoluta resistance in L. hirsutum f. typicum. The peak 14 occurred only in the variety Santa Clara with an increased tomato susceptibility to T. absoluta. The probable compounds associated with peak 8 were the sesquiterpenes 2,5,5-trimethyl-1,3,6-heptatriene, (+) camphene, farnesene or santalol. The probable substances associated with peak 9 were the sesquiterpenes alpha-bergamotene, farnesene, ß-sinesal, or farnesol. No substance associated with peaks 10, 12 and 14 were found.
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(original language: Portuguese)
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Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phthorimaea absoluta		Brazil (south)