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Herbivore-attacked plants produce specific volatile substances that represent important cues for host finding by natural enemies. The fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a voracious herbivore and usually feed on maize in all periods of the day. Given that plant needs light to synthesize de novo herbivore-induced volatiles, volatile blend may be changed depending on time of the day the plant is induced, what could interfere in natural enemy foraging. In this sense, the current study aimed to investigate differential attractiveness of maize elicited by fall armyworm regurgitant under light and dark conditions to its specialist larval parasitoid Campoletis flavicincta (Ashmead) (Hymenoptera: Ichneumonidae). All bioassays were conducted in Y-tube olfactometer to assess parasitoid response to odors from undamaged maize, mechanical damage, and regurgitant-treated plants at 0-1, 5-6, and 24-25 h after induction. The results showed that naïve wasps were attracted to volatiles emitted by nocturnal regurgitanttreated maize at 5-6 h, but not to odors from diurnal regurgitant-treated plants. The differential attractiveness is likely due to blend composition as nocturnal regurgitanttreated plants emit aromatic compounds and the homoterpene (3E)-4,8-dimethyl-1,3,7-nonatriene in larger amounts than diurnal-treated plants.

18, 20, 22, 25, 28, 30, and 32ºC 70±20% RH, . Lower threshold temperatures (TT) and thermal constants (K) for the egg, larval and pupal stages were 12.7ºC and 51.2 GDD, 13.5ºC and 290.9 GDD, 13.8ºC and 108.4 GDD, respectively; TT and K values for the biological cycle were 13.8ºC and 436.3 GDD.

Plant volatiles are important cues for the orientation of herbivorous insects. It is possible that these compounds indicate whether the plant is suitable for feeding and larval development, or for mating aggregation. Vernonia condensata (Asteraceae) is known to attract species of leafhoppers, most of them important vectors of the citrus variegated chlorosis (CVC). In this study, we evaluated the role of volatiles of V. condensata on the orientation of Bucephalogonia xanthophis (Hemiptera: Cicadellidae). Four-arm olfactometer bioassays showed that only males were attracted to the volatiles of the host-plants Citrus sp. and V. condensata. Furthermore, fresh leaves of V. condensata induced a stronger response than volatiles from hexane-extracted leaves. This study opens the possibility to utilize V. condensata volatiles for pest management programs of B. xanthopis. Key words: plant-herbivore interaction, leafhopper, trichomes ATRATIVIDADE DE Bucephalogonia xanthophis (CICADELLIDAE) POR VOLÁTEIS DE SEU HOSPEDEIRO NATURAL Vernonia condensata (ASTERACEAE)RESUMO: Os voláteis de plantas são sinais importantes para a orientação de insetos herbívoros. É possível que esses compostos indiquem que a planta é apropriada para alimentação e desenvolvimento larval, ou para agrupamento reprodutivo. Vernonia condensata (Asteraceae) atrai espécies de cigarrinhas, muitas delas vetores da clorose variegada dos citros (CVC). Neste trabalho, foi avaliado o papel dos voláteis de V. condensata na orientação de Bucephalogonia xanthophis (Hemiptera: Cicadellidae). Bioensaios em olfatômetro de quatro braços mostraram que somente os machos foram atraídos pelos voláteis das plantas hospedeiras Citrus sp. e V. condensata, sendo que os voláteis das folhas frescas de V. condensata induziram uma maior resposta quando comparada aos extratos hexânicos da planta. A possibilidade de usar os voláteis de V. condensata abre novas perspectivas para programas e alternativas para o manejo de pragas. Palavras-chave: interação planta-herbívoro, cigarrinha, tricomas

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