Evaluation of the Response of Nine Grasses to Collaria Scenica (Hemiptera: Miridae) Attack at Sabana of Bogota

During 1997, the response of the grasses "Falsa poa" (Holcus lanatus), "Azul orchoro" (Dactylis glomerata), "Kikuyo" (Pennisetum clandestinum), and raigras (Lolium spp.): Bisón, Aubade, Rust Master, Bestfor, Tetrelite y Dalita, against attack by the grass bug C. scenica was evaluated under mesh house, experimental and commercial plots conditions. Under mesh house, the damage caused to grass, oviposition preferences and number were evaluated. Different grass species were seeded in plots under field conditions in order to evaluate the damage to grass and the population level of bug and beneficial insects. The same evaluation was developed under commercial conditions during recuperation time on Tetrelite, Bestfor and Bison plots. The results obtained in plots related to damage revealed significant differences, the kikuyo being the grass most liable to suffer damage and the Bestfor the most tolerant. The other grasses had an intermediate response. According to the symptoms observed in each grass, damage scales were established for Raigras, Falsa poa and Azul Orchoro, which differed in affected foliar area. Oviposition preferences and differences were not observed. The highest heigh of oviposition was a Rust Master over sheaths at 17,6 cm. Kikuyo revealed the lowest average egg number through oviposition, showing significant differences from the rest of the grasses. The plots under field and commercial conditions did not differ in damage suffered, perhaps because the insect population was very low. However, increments were observed between three and four weeks and the natural enemies increased too. The Tetrelite grass had high pest population but low damage. These results, damage and bug preference for the different grasses evaluated did not follow a defined model; therefore, in establishment of it is recommended to use a mixture of these grasses and legumes.