New study links Attraction and Oviposition of Tuta absoluta Females in Response to Tomato Leaf Volatiles

A new study published recently in the Journal of Chemical Ecology has demonstrated clearly the role of tomato leaf volatiles on the attraction and egg laying behaviour of mated females of Tuta absoluta. The study showed a significant difference in the egg laying behaviour of Tuta absoluta on three Tomato varsities. There was also a difference in the type and ration of component which may play role in influencing the insect behaviour. The study opens the door for a greater screening of Tomato varieties which are less susceptible and focusing the attention toward the plant own resistance rather than the dependence on pesticides.

.................. Abstract The tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) is a devastating pest of cultivated tomato Solanum lycopersicum throughout South and Central America and Europe. We aimed to characterize the behavioural mechanisms and the chemical cues involved in host selection of T. absoluta females by chemical analysis of tomato leaf volatiles, wind tunnel attraction assays, and oviposition bioassays. Tomato leaf odour elicited in mated females upwind orientation flight followed by landing as well as egg-laying, demonstrating the essential role of plant volatiles in T. absolutahost-finding behaviour. In wind tunnel and oviposition choice experiments, T. absoluta females significantly preferred tomato S. lycopersicum over wild tomato Solanum habrochaites, which is resistant to larval feeding. This indicates that leaf volatiles provide information on the suitability of plants as larval hosts. Mated females also discriminated three cultivars of S. lycopersicum according to their volatile profiles. Headspace collections from leaves of these three cultivars contained large amounts of β-phellandrene, followed by limonene, 2-carene, and (E)-β-caryophyllene, which together accounted for more than 70% of tomato foliage headspace. Most leaf volatiles were released by all three cultivars, but they showed significant differences with respect to the presence of a few minor compounds and blend proportion. This is an initial study of the volatile signatures that mediate attraction and oviposition of tomato leaf miner T. absoluta in response to its main host, tomato. ............................................................................ Journal of Chemical Ecology (June 2011), 37 (6), pg. 565-574 Magali Proffit; Göran Birgersson; Marie Bengtsson; Ronaldo Reis; Peter Witzgall ; Eraldo Lima

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