| dc.description.abstract | Thaumastocoris peregrinus (Carpintero & Dellape) (Hemiptera: Thaumastocoridae), known as bronze bug eucalyptus causes leaf yellowing and defoliation of Eucalyptus plants. Sought alternative forms of control, the use of plant extracts is considered a promising measure. In this sense, the objective of this study was to evaluate the effect of plant extracts of camomila (Matricaria chamomilla), chapé-de-couro (Echinodorus grandiflorus), romã (Punica granatum), espinheira-santa (Maytenus ilicifolia) and manjerona (Origanum majorana) on adults of T. peregrinus. For this three bioassays were conducted: Containment test, repellency test and High Performance Liquid Chromatography (HPLC). For the containment test, eucalipto leaves were collected and immersed in the solution for five seconds plant extract 5%. These were placed in a laminar flow hood to evaporate the water and cut to 2,4 cm in diameter. There after, the sections were placed inside glass tubes, with an adult insect T. peregrinus, totaling 12 repetitions. For repellence tests, the treatments and trimming the leaves were performed according to the previous test. Were distributed and treated leaves jagged edges of a petri plate (150x20 mm) lined with moist filter paper, each plate received 10 adult insects. Both experiments were kept in a climatic chamber BOD (26 ± 2 ° C, RH 60 ± 10%, photoperiod of 12 hours). Evaluation of survival / longevity T. peregrinus the containment test was performed every 6 hours, and for evaluating the number of fecal deposits from repellency test, performed every 24 hours. For the realization of High Performance Liquid Chromatography (HPLC), ten microliters of each sample were injected into a liquid chromatograph coupled to a fluorescence detector and a photodiode array detector, following routine procedures. To test the survival/longevity T. peregrinus was observed that there was no difference between treatment and control, all of which caused a reduction in longevity/survival of T. peregrinus. In repellence tests, extracts applied not repelled feeding T. peregrinus after 24 and 48 hours. After 72 and 96 hours was able to verify that contaminated extracts leather hat, camomila and holy thorn leaves showed fewer feces of T. peregrinus, when compared to the control. After 120 hours of review, extracts leather hat and espinheira-santa showed potential repellency. With HPLC analysis, we identified the presence of gallic acid in romã extracts and manherona, camomila extract in caffeic, ferulic extract in leather hat and camomila extract and coumaric in leather hat. The extract of espinheira santa had a shorter survival period/longevity than others, indicating its potential as a repellent. When the insects were subjected to contact with camomila extract, these showed a survival/longevity of only 2,8 days. The extracts of espinheira-santa holy and camomila are considered respectively, repellents and insecticides in controlling agents T. peregrinus. | |
