Seasonal phenology of Closterotomus (Calocoris) trivialis Costa(Hemiptera: Miridae) on olive trees and associated host plants
Abstract: The seasonal appearance and population abundance of nymphs and adults ofC. trivialis were studied by weekly canopy shaking samplings in 2 olive groves in Chania,Greece, from January until May 2009. In each sampling, one twig per olive tree, about 20-25cmlong containing 5-6 shoots, was shaken on a beating tray and the fallen individuals of C. trivialiswere counted. In addition, samples were taken from weed species referred in the literature asalternative host plants for C. trivialis. For the weeds similar procedure with olive sampling wasfollowed, in which each plant was individually shaken. Each sampling comprised 15 replicationsfor the olive trees and 15 replications per weed species. Results showed that 1st and 2nd nymphalinstars of C. trivialis were first recorded on weeds on January 15th. Adults were first showed onMarch 19th and were present by late May, in both olive groves. However, population recoveredfrom olive trees was extremely low in general, recorded from late February until early May.Significant differences were observed in the total number of live individuals (nymphs and adults)per plant among the various host plants. Specifically, more C. trivialis individuals were recordedon Mercurialis annua L. (Euphorbiaceae) compared with Sinapis alba L. (Brassicaceae),Parietaria officinalis L. (Urticaceae), Urtica sp. (Urticaceae), Sonchus oleraceus L. (Asteraceae),Malva silvestris L. (Malvaceae) and Olea europaea L. (Oleaceae). No significant differenceswere observed between the two olive varieties (Koroneiki, Tsounati) considering the total numberof live individuals of C. trivialis per twig. Collected information on host plant preference ofC. trivialis can be helpful in predicting its occurrence and movement among crop and non crophost plants.