RESUMEN
Thyrinteina arnobia (Lepidoptera: Geometridae) is a native American species. Despite its historical importance as an insect pest in Eucalyptus plantations, more information is needed regarding the population diversity, demography, and climatic variables associated with its distribution in different regions of Brazil. We used a phylogeographic approach to infer the genetic diversity, genetic structure, and demographic parameters of T. arnobia. We also conducted an ecological niche modeling (ENM) to predict suitable areas for T. arnobia occurrence in Brazil and other countries worldwide. Although T. arnobia populations have low genetic diversity in Brazil, we identified mitochondrial haplogroups predominating in different Brazilian regions and high ФST and ФCT values in AMOVA, suggesting a low frequency of insect movement among these regions. These results indicate that outbreaks of T. arnobia in Eucalyptus areas in different regions of Brazil are associated with local or regional populations, with no significant contribution from long-distance dispersal from different regions or biomes, suggesting that pest management strategies would be implemented on a regional scale. In Brazil, the demographic and spatial expansion signals of T. arnobia seem to be associated with the history of geographical expansion of Eucalyptus plantations, a new sustainable host for this species. ENM indicated that isothermality and annual rainfall are critical climatic factors for the occurrence of T. arnobia in tropical and subtropical areas in the Americas. ENM also suggested that T. arnobia is a potential pest in Eucalyptus areas in all Brazilian territory and in regions from Africa, Asia, and Oceania.
Asunto(s)
Ecosistema , Eucalyptus , Variación Genética , Filogeografía , Animales , Eucalyptus/parasitología , Brasil , Lepidópteros/genética , Lepidópteros/fisiología , Mariposas Nocturnas/fisiología , Mariposas Nocturnas/genética , FilogeniaRESUMEN
Cultivation of species of the genus Eucalyptus is important for the Brazilian economy, with 6.97 million hectares planted. Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), detected in Brazil in 2003, has dispersed and now damages Eucalyptus crops in all regions of this country. The location and identification of entomopathogenic fungi isolates may increase the options for integrated pest management. The objective of this research was to evaluate the pathogenicity of Cordyceps cateniannulata and Cordyceps javanica isolates to G. brimblecombei. Ten nymphs of G. brimblecombei, with or without lerps, were placed per Eucalyptus leaf cut with one of its edges on hydroretentive gel inside Petri dishes. The fungi isolates were suspended in a solution of Tween 80 (0.1%) at the concentration of 1.0 x 108 conidia mL-1 and sprayed on the G. brimblecombei nymphs. The mortality of this insect was evaluated daily for seven days, and the dead individuals were transferred to humid chambers. The conidia viability of the isolates was greater than 93%. The mortality of G. brimblecombei nymphs, seven days after the application of the fungi, was 100%. This is the first report of the pathogenicity of C. cateniannulata and C. javanica isolates, occurring naturally in the field, to G. brimblecombei.