Electrophysiological responses of eucalyptus brown looper Thyrinteina arnobia to essential oils of seven Eucalyptus species

Abstract

A lagarta-parda, Thyrinteina arnobia, causa grandes prejuízos à cultura do eucalipto, destacando-se como o principal lepidóptero desfolhador; portanto, medidas alternativas de controle são necessárias. Neste trabalho foi avaliada, pela técnica de eletroantenografia (EAG), a interação dos voláteis dos óleos essenciais de sete espécies de Eucalyptus, frente às antenas de fêmeas e de machos de T. arnobia. Foram também identificados 28 compostos voláteis bioativos contidos no óleo essencial de E. grandis, utilizando a detecção eletroantenográfica acoplada à cromatografia a gás (CG-EAD). Estes resultados indicam que CG-EAD é uma ferramenta muito útil na triagem de compostos bioativos presentes em extratos de plantas e sugerem que T. arnobia utiliza vários destes terpenos como sinais para encontrar seu hospedeiro.Eucalyptus is frequently attacked by the Brazilian eucalyptus brown looper, Thyrinteina arnobia. This caterpillar is regarded as the main lepidopterous pest of Eucalyptus and yet no practical and environmentally acceptable method of control currently exists. Electroantennographic techniques (EAG) have never before been used to detect semiochemicals that affect the behavior of T. arnobia. Thus, in this work, the ability of T. arnobia males and females to detect volatile essential oils of seven Eucalyptus species was investigated by EAG. We demonstrated that T. arnobia antennal olfactory system clearly showed differential sensitivity to several compounds, by coupled gas chromatography-electroantennographic detection (GC-EAD). Twenty-eight compounds were identified that elicited responses in T. arnobia, indicating that GC-EAD analysis may well be a useful means of screening active plant extracts for compounds that contribute to the observed behavior of this defoliator. The results also suggest that this species uses several volatile cues to find its host.Keywords: Thyrinteina arnobia, Eucalyptus brown looper, Eucalyptus spp., essential oil, electroantennography IntroductionThe genus Eucalyptus, native to Australia, is widely cultivated in Brazil, covering an area of more than three million hectares. This country is the world's leading producer of eucalyptus-based fiber and of the 6.3 million tons of cellulose produced here annually, the majority is extracted from this exotic species. Eucalyptus plantations also supply wood to the furniture industry and help to reduce the pressure on native forests. 1The Brazilian eucalyptus brown looper, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), is the most harmful of the Eucalyptus pests in Brazil, causing severe losses in wood production through defoliation. This moth attacks several genera of the Myrtaceae family, including six Psidium species, eight Campomanesia species, nine Eugenia species and twenty Eucalyptus species. Biological data on T. arnobia, reared on leaves of Eucalyptus spp, have been recorded by a number of groups. 2-6Several strategies have been tried and considerable effort spent on the development of methods to control this pest, yet no p...

Quality Assessment of the Essential Oil from <i>Eucalyptus globulus</i> Labill of Blida (Algeria) Origin

“…Our findings are similar to those from Tsiri et al [21] and Cimanga et al [16], who revealed that the major components of Eucalyptus oils was 1,8-cineole. The chemical profiles of a variety of other Eucalyptus species have been published [22,23], and are comparable to our results. Nevertheless, Singh et al (22) extracted the leaf oil of E. urophylla from India, with p-cymene (75.0 %), α-pinene (7.0 %), and α-terpinene (4.0 %) being the main compounds.…”

Chemical Composition and Bactericidal Activities of the Leaf Essential Oil of Eucalyptus maculata Hook

“…1,8-cineole which is a principal component of most Eucalyptus essential oils was of very low percentage in in the leaf essential oil of E. maculata grown in Nigeria (Table 1). This result is similar to what was obtained from the leaf essential oil of the plant from Brazil, Iran and Tunisia [30][31][32]. Most of the secondary metabolites present in this essential oil were reported to have good pharmacological properties [33][34][35][36].…”

Chemical&nbsp;Variability and&nbsp;Biological Activities of&nbsp;<em>Eucalyptus</em> spp. Essential Oils

“…In general, it affords good extraction yields of EOs as observed in the studies from plants cultivated in India [54] and in Benin [99] (4.8% and 4.6% yields, respectively). Lower oil yielding species were found, however, in India (0.6%) [26], in São Paulo State, Brazil (0.66%) [70,71] and Colombia (0.70%) [102]. Typically, citronellal is the major constituent in E. citriodora EOs.…”

“…For most E. camaldulensis EOs, 1,8-cineole is the major constituent. This oxygenated monoterpene has been found in quantities superior to 50% in EOs produced by plants cultivated in Egypt (60.3%) [63], the Democratic Republic of the Congo (58.9%) [53], Nigeria (70.4%) [67], Brazil (52.8%) [70,71] and Iran (74.7%) [69]. Plants cultivated in Kenya [78], Northern Cyprus [64] and Argentina [75,76] …”

“…Essential oils with high content of citronellal (>70%) have been reported in several studies conducted in Brazil, in the states of Minas Gerais (94.9%) [95]; Pernambuco (89.6%) [101]; Goiás (82.3%) [91]; São Paulo (76.0%) [70,71], (71.8%) [94]; Ceará (71.8%) [100]; and Sergipe (71.1%) [103]. Essential oils rich in citronellal have also been found in plants from Democratic Republic of Congo (72.7% of citronellal) [53]; South Korea (73%) [92] and Argentina (76.0%) [86].…”